No start situation, 1400 miles on OBD1.

[Susanoo]

I've thrown this around the facebook group but its time I posted it here for more ideas and maybe even a for sure fix. A little background, I performed what appeared to be a successful OBD1 conversion, I decided to drive around for a while fixing small things here and there and working on what codes were stored...however some things came up in life and I was distracted from the codes and continued to drive it until the junkyard dizzy's shaft seal failed and oil filled the dizzy. One reman dizzy later it worked great for a day, then a day later I started seeing the same things. I freaked and pulled the dizzy cap thinking the same thing had happened. Nothing. So i drove it around trying to see if a part would go or something would stick out more but nothing until it died and I parked it. It wouldnt start at all, so I started going through things and pulled codes, originally it was saying codes 6, 7, 10, and 20. I went through some more things and found the ALT charging signal broken off from a bad solder connection. I soldered that back, no change, so I got told to check the ECU. Once I pulled it out I knew it couldnt be helping but hoped and really thought it may be the issue. I got a ECU from a fellow 3geez member named Gio. I socketed my chip and plugged it all up, no change, no start at all. I started tracking down wires and checking circuits. The ECT circuit seems to be correct checking by schematics. I have replaced the sensor twice and no change. Now I've honestly had a code 6 since I did the EFI conversion but couldnt figure it out then either. So I have no idea why its throwing code 6. However I have done a wire tuck and im really starting to wonder if I crossed some wires somewhere or connected like wires when I shouldnt have. Since I swapped the ECU I pulled codes and I've currently got code 6, 10, and 20. Still a no start situation. I've got spark and fuel pressure primes to 30 psi and holds during starting.

Now the current suggestions stand at something wrong with the injectors firing (untested officially, however tried a 12 volt test light and only managed to get it to light up by finding the hot side of the plug. OR the main relay...which could be possible since I got it out of a junkyard 89 prelude.

However Im really tired of guessing and its been parked for 2 weeks. I need my car back.

[89T]

Did you check your ecu grounds? Sg2 (d22)controls the grounds for the coolant and intake air temp sensor. The tps, and oxygen sensor grounds are on the same loop. This may cause a no start condition.

[Susanoo]

Ok then theres no way I would have crossed or otherwise misconnected the sensor grounds because they seem to be two different colors and I traced the sensor ground between the intake air and coolant temp sensors but thinking now ...I cant remember if I checked that back to the ecu...Let me go check this real quick...

I like where this is going now...Thanks for the reply 89T.

EDIT: Its sprinkling rain right now...Im waiting for it to stop..

[89T]

My book shows green/white. No problem.glad i can help.
As for the eld. I turned that off in the tuning software.

[89T]

The wiring On the adapter harness should be obd1 (d22) to obd0 (c12)

[Legend_master]

I don't know if the obd1 swap uses the factory fuel pump relay, if it does I would try resoldering that first. They are very problematic.

[Rendon LX-i]

check your ecu ground like jerry said. check main relay an spark fuel of course. sounds like a ecu problem or fuel pump. i had a no start having a shitty fuel pump.

[89T]

So how far did we get?

Another thought. Make sure the group of grounds on the intake manifold are good.

[Susanoo]

So sorry im just getting back, i've been busy with work and general day to day issues. ANYWAY....I do have news, I found that I had incorrectly swapped a wire between the ECT and the sub cooling fan switch? right?...well I traced it back this time and connected it correctly, I even put another plug on it since the wire was breaking off at the silicone. I traced back the IAT and I dont really know what I did...but its not connected to SG2, I found a connection to it from the wire I had connected to the sub cooling fan switch...so here in a few im gonna label the injectors and hopefully pull the harness out enough that I can visually trace it back...

And I cant start it right now anyway because the battery ran down from sitting for so long and starting and starting and starting...so I'll know in an hour.

[Susanoo]

So it runs again! I also found out that I had put the new cam key on backwards and after flipping it around it started up a little slow and smoked a little at first but after it warmed up it was fine...Its still kinda skippy at the throttle though and im wondering if thats not the TPS that needs to be readjusted. I also need to properly time the ignition with a light and that will help more. All in all I guess its just adjustments from now but hopefully continued help from you guys will get this thing running better then ever. Im also thinking about getting another idle air control valve since it hums with the key turned on...

[gfrg88]

Awesome! Glad you got her back up and running! :cheers:


A nice street tune would probably do you wonders

[Susanoo]

Yea it probly would. Any idea why the idle drops real low and bounces back up and down?

[Susanoo]

Yea something still isnt right somewhere, I checked again and I have codes 7, 10, and 20. I know what needs to be done to fix the code 10, I messed up the engine harness somehow...

I checked on the TPS and I got between 6 and 8 volts on the red wire...which is apparently way off.

[Rendon LX-i]

Daaamn that is not good .sounds like you have a short or voltage in the wrong wire you should only have 5 volts

[Susanoo]

Lets just correct that whole sleepy post....

I've been told and read that the red wire should only be getting .50 with the key on and throttle closed...Where should I be finding this 5 volts?...

[Susanoo]

So I messed around, swapped the dizzy and when I did I got code 14 and so I swapped IAC valves and its idling much better but its still got the fluttery throttle...

Just keeping people updated :P I havent had time to pull the harness yet...hopefully soon.

[Susanoo]

I probed the yellow and red wires on the tps and found exactly 5.01 volts on yellow and 7.71 volts at closed on red. I'm just confused cause if I had crossed a wire I should have had this symptom on.first start..

[Susanoo]

Did you check your ecu grounds? Sg2 (d22)controls the grounds for the coolant and intake air temp sensor. The tps, and oxygen sensor grounds are on the same loop. This may cause a no start condition.

So let me get this straight... ECT, IAT, TPS, and O2 are all on SG2?

Btw im still using the one wire oxygen sensor...so I dont have a ground coming off it.

I've got the harness out now fixing things up and checking things out and I've found that the ECT is actually on its own two pins. So im assuming what I need to do is connect the other grounds to that wire and thats what im going to do since you said all these sensors are on the same sensor ground.

[Susanoo]

Ok I went through the harness and fixed the sg2 problem and all codes are gone except the code 20. However theres still a flutter in the throttle and it wont pull until like 4-5k rpms, then it damn near throws you to the seat.

[gfrg88]

Reason why it's probably bogging down like that is your o2. Fix, or disable it and I'm sure it will pull a ton smoother. The ELD, well I don't know the fix for that, since I disabled it...

[Susanoo]

New O2 sensor too man. I damn near have all new sensors with less then 5000 miles on them.

I got a local guy that I've been keeping updated and he said today that he would have to look at it to figure out whats going on and said that its a weird but typical honda thing...idunno.

[stat1K]

i'm really not digging this new forum style but anywho, the tps voltage should be .50 or close to at closed throttle, then open the throttle all the way should be the 5v. the bog sounds like when my tps was loosening itself because of the screws. how is yours attached? replacement m6 or the original sheer bolts?

[Susanoo]

i'm really not digging this new forum style but anywho, the tps voltage should be .50 or close to at closed throttle, then open the throttle all the way should be the 5v. the bog sounds like when my tps was loosening itself because of the screws. how is yours attached? replacement m6 or the original sheer bolts?

Yea I liked the classic look to go with a forum about a classic car ;) haha but yea anyway, after I fixed the SG2 in the engine harness I reproped the TPS and recalibrated to .501 volts and I used the original sheer bolts but i want to get better ones. Its on pretty tight. It wont move after you tighten it, I tried.

[Susanoo]

None of you veterans are going to chime in? I want my stuff fixed for Import Alliance and besides that I need it for work and personal...this is my daily driver too :(

[89T]

there is no eld fix. You need to disable it. The eld is located in the fuse box of the of the civic. You can try there. you probably need to install a 4 wire o2.

[Susanoo]

there is no eld fix. You need to disable it. The eld is located in the fuse box of the of the civic. You can try there. you probably need to install a 4 wire o2.

Well...can I not take it out of the fuse box and install it to mine or is it that worthless?
Elpuma on here used the original one.wire if I followed his thread correctly. Besides. I got told by three honda guys to check the cat. For the first month of FI I didn't have a correctly connected map sensor so I dumped fuel for a month. So for lack of help here besides 89T, I'm gonna rely on them. At one time I felt welcome here. Not anymore.

[89T]

Well...can I not take it out of the fuse box and install it to mine or is it that worthless?
Elpuma on here used the original one.wire if I followed his thread correctly. Besides. I got told by three honda guys to check the cat. For the first month of FI I didn't have a correctly connected map sensor so I dumped fuel for a month. So for lack of help here besides 89T, I'm gonna rely on them. At one time I felt welcome here. Not anymore.

I was looking into the eld fix some time ago, but after figuring out it could be disabled. That was the easier option. If you are throwing a code. the ecu automaticaly puts it self into limp mode or called safe mode. It will will richen up the fuel and make timing changes. This could be what you are experiencing. The first thing that needs to be done is get that code fixed or disable the sensor. What software are you using?

Trust me you are very much welcome here. The knowlege base on obd1 swap/swap dianostics is limmited to a handful of us that have done the swap. Most, if any did not have the same problems you are having. I will continue to help as much as I can.

[elpuma]

Susanoo when you cut the 3 wires off the obd0 dizzy did you ground the black one on the new obd1 dizzy? There should of been a black, black/yellow, and a blue wire.

[2oodoor]

None of you veterans are going to chime in? I want my stuff fixed for Import Alliance and besides that I need it for work and personal...this is my daily driver too :(

Chime in on what? You state a problem then you come back later with reasons why you never came back, then state you fixed whatever then bring up another problem. Its hard to follow man.
You should never have over 5.xx volts those upper engine sensors for the ecm. This does not include servos of the ecm or o2 snsors, generally speaking. 5 volt reference signal is just that, signal voltage not apPlication voltage. The two are isolated currents. 7 volts sounds like a wrong wire feeding in to the commnication harness for the ecm and/or a grounding problem. That could be happening at a relay as well, back feeding 12v current in to the 5 v reference ecm signal circuits.
You have a way to read all the data at once?
You are getting good tips here by the more experienced obd swap guys so I hope you find their help usefull.

[2oodoor]

If you think you have clogged cats though just pull out an o2 sensor, that relieves the back pressure and you can test drive it in open loop. That will tell you if its stopped up without cutting up your system.

[Susanoo]

I was looking into the eld fix some time ago, but after figuring out it could be disabled. That was the easier option. If you are throwing a code. the ecu automaticaly puts it self into limp mode or called safe mode. It will will richen up the fuel and make timing changes. This could be what you are experiencing. The first thing that needs to be done is get that code fixed or disable the sensor. What software are you using?

Trust me you are very much welcome here. The knowlege base on obd1 swap/swap dianostics is limmited to a handful of us that have done the swap. Most, if any did not have the same problems you are having. I will continue to help as much as I can.

I guess thats just how honda works...its not important so lets make the engine run like shit anyway -_- The only way I can disable it is to have yet another chip burned disabling the ELD. I have a copy of crome free but I havent figured everything out yet and I have no way of burning a rom anyway.

I do understand theres a limited number of people but OBD1 is simple...ITS OBD1! The only difference between my obd1 and a teg that comes with obd1, for example, is the wiring and how the wires are routed. Course, yes, 4 wire O2 is usually found on obd1 but I dont have one. Simply put, even though all this shit was done by me and its not exactly like someone elses. People on here have a general understanding of things and I really dont care if things are thrown at me at this point cause I cant figure it out and I've already thrown over 500 dollars into it THIS month alone.

elpuma, dont you run the original O2 sensor??? I followed your build and guide closer then anyone and straight copied your pinout. Only difference is I used the old EGR signal wire for the ICM signal to aid in wire tucking.


Susanoo when you cut the 3 wires off the obd0 dizzy did you ground the black one on the new obd1 dizzy? There should of been a black, black/yellow, and a blue wire.

The blue I put on the negative post of the coil, the black goes to the negative of the coil and the black/yellow goes to the positive of the coil...as I read on here..


Chime in on what? You state a problem then you come back later with reasons why you never came back, then state you fixed whatever then bring up another problem. Its hard to follow man.
You should never have over 5.xx volts those upper engine sensors for the ecm. This does not include servos of the ecm or o2 snsors, generally speaking. 5 volt reference signal is just that, signal voltage not apPlication voltage. The two are isolated currents. 7 volts sounds like a wrong wire feeding in to the commnication harness for the ecm and/or a grounding problem. That could be happening at a relay as well, back feeding 12v current in to the 5 v reference ecm signal circuits.
You have a way to read all the data at once?
You are getting good tips here by the more experienced obd swap guys so I hope you find their help usefull.

Look dude I didnt know there were multiple issues okay? I fix one and find another, what the hell do you want me to say? sorry? All I can say is that you'll have to put it together in your head and compare everything I've done with what you know could be wrong now. I fixed all the sensor issues when I repaired SG2. Only the ECT was connected to the ECU properly.

What do you mean by a way to read all the data at once??

I do find their help useful, I do...especially 89T and elpuma, I recognize their expertise over many other peoples because they stay more active here then anyone i've ever seen.

[89T]

I'll take a look at the wiring diagram when i get a chance. It might be a couple of days out.

Look into neptune/demon for a fully funtionable software-hardware package. I know its more money but the package is unbeliveable.

[Susanoo]

I'll take a look at the wiring diagram when i get a chance. It might be a couple of days out.

Look into neptune/demon for a fully funtionable software-hardware package. I know its more money but the package is unbeliveable.

I'll try to double check some things. One thing I'll mention is that I had a guy come over the other night and unplugged the sensors one by one to note the change and when he unplugged the TPS, nothing, no change. I thought it should have made a difference and he said it should have idled up, down or done the wah pow, wah pow, wah pow, wah pow...typical of the tw sensor.

And wait...what? software-hardware package? Right now man I just wanna get this running right...If other people can run good on stock ecu's then why cant I, at least for now...I mean I plan for better stuff but its all in time.

[elpuma]

I pulled my black wire off to see if it changed anything and nothing. I don't have my black wire hooked up with the blue one like you do though. I just hooked mine to the body of the dizzy.

I too have a slight idle flutter but i believe that's is do to the aggressive cam i run in the car.

I was running the original o2 sensors but after i got it street tuned they were disabled.

[89T]

With the neptune, you keep the honda ecu, but you add a board to the ecu(demon). Let me get a link.

http://www.hrtuning.com/pages/category/neptune-rtp

this will make the stock ecu into a fully funtional "stand alone" ecu. Real time tuning and no chip burning. Just plug it in to a laptop and go.

On the TPS you have 3 wires. 5v+/ground/signal. Signal should read 0v closed and 4.5-5v wide open throttle. do you have that?

[Susanoo]

With the neptune, you keep the honda ecu, but you add a board to the ecu(demon). Let me get a link.

http://www.hrtuning.com/pages/category/neptune-rtp

this will make the stock ecu into a fully funtional "stand alone" ecu. Real time tuning and no chip burning. Just plug it in to a laptop and go.

On the TPS you have 3 wires. 5v+/ground/signal. Signal should read 0v closed and 4.5-5v wide open throttle. do you have that?

I'm broke either way dude.

Yea I have 5 volts on yellow, but I read in a manual that closed...red should put out .50 and then the 4.5-5 volts fully open.

I just pulled codes too and found 10 and 7 again so I have no idea what the hell is going on.

[89T]

Well fuck. Back to square 1. So, if all the grounds are good, and you soldered all connections.. metered all the sensors to make sure all is good with those... I'd hate to say that you are going to have to go through all the connections again.

you are using the interior harness from an efi accord? what year accord it came out of.
what engine harness? I assume off the same efi accord as well.
Painfully, the tuck harness will come into question as well. Did you get connectors off another accord or did you just cut and splice?

It's hard for me to find the problem with out getting my hands on it.

I need as much feedback and detail you can give in order to help you out. If you can give pictures on connections and such. It will help out.

[Susanoo]

Well fuck. Back to square 1. So, if all the grounds are good, and you soldered all connections.. metered all the sensors to make sure all's good with those... I'd hate to say that you are going to have to go through all the connections again.

you are using the interrior harness from an efi accord? what year accord it came out of.
what engine harness? I assume off the same efi accord as well.
Painfully, the tuck harness will come into question as well. Did you get connectors off another accord or did you just cut and splice?

It's hard for me to find the problem with out getting my hands on it.

I need as much feedback and detail you can give in order to help you out. If you can give pictures on connections and such. It will help out.

Ask and you shall receive...Im gonna go right now and take pictures of everything...but after that im gonna go to the range and relieve my stress of this car. -.- However I should reply within the next hour or two so expect my reply :) Thank you so much 89T. Umm As far as the harness, I got it from an 88 if i remember correctly. I know at some point I questioned myself and remembered more confidently then. I did also take connectors from a 4G Accord harness because the ones from my FI harness were kinda worn. I recently repaired the ect with a gray one from the same donor harness. I tried to copy wire colors or patterns as closely as possible. Like on the IAT circuit its a white/red wire, so I used some plug from the 4G harness that had a yellow/black(?) and tied those together because I figured these are just resisters and a guy on the facebook said it shouldnt matter...soo....you can confirm or deny that one if you would please.

[89T]

Ok. The only plugs you needed from a 4g were for the dizzy. If the plugs are the same and the wiring was carfully matched up to the same position as the stock accord plug. It should be good. I would not rely on wire colors.

[2oodoor]

Just to clarify: where on the harness did you resolder the ALT signal mentioned in the first post? Also is there Anything else not working as it should, electronic or electrical?(tach, guages , idiot lights etc)
Thanks , anything else you can think of could help someone help you figure this out.

[89T]

check with this and read the post

http://www.3geez.com/forum/showthread.php?69021-getting-started-again-89T&p=1030003&viewfull=1#post1030003

[Susanoo]

Ok. The only plugs you needed from a 4g were for the dizzy. If the plugs are the same and the wiring was carfully matched up to the same position as the stock accord plug. It should be good. I would not rely on wire colors.

Well here are the pictures you requested. Just ask and I'll get whatever angle you want or take pictures of whatever you need me to.

http://s1272.photobucket.com/albums/y392/89obd1accord

Now when you say if I carefully lined and matched things up...what do you mean by that? There's a specific polarity on these sensors? I only used the 4g plugs because I couldnt find a 3gee harness with good plugs and because I like the gray plugs over the yellowish white old as hell ones from the 3gee.


Just to clarify: where on the harness did you resolder the ALT signal mentioned in the first post? Also is there Anything else not working as it should, electronic or electrical?(tach,guages , idiot lights etc)
Thanks , anything else you can think of could help someone help you figure this out.

I actually paid very close attention to the two white/red and had to go back during initial body harness install to verify I had them run correctly and I do. The ALT RF and IAT are on proper separate circuits.

After I reconnected the SG2 and started I noticed my fan was on. Umm a weird thing is if I leave the key turnedo and don't start the engine
..the oil pressure idiot light flashes but the gauge reads fine. Everything else seems to work as it should.

[Susanoo]

check with this and read the post

http://www.3geez.com/forum/showthread.php?69021-getting-started-again-89T&p=1030003&viewfull=1#post1030003

I read the post man but I'm not at home right now and don't have my obd1 pinouts on hand. I remember soldering two fuel pump relay wires to a single on the conversion harness. I also used new shielded wire for the ckp, not the o2 wires.

[Legend_master]

Alright bare with me if this has been said, cause I did not read all the replies to this. As far as the TPS, your car should almost die, or die for sure if you disconnect the TPS. That and the IAT sound like wiring issues. When I did the second b-swap I had a similar issue with some sensors. Ended up running wires directly from the ecu out my window and right to the sensor. Helped me to track down a short in part of the "factory" harness I used. You have 3 options with the ELD, 1) swap in an obd1 fusebox 2)chip the ecu and turn it off 3)find a Jdm obd1 ecu since they do not use ELDs. You can also disable the o2 sensor if you don't want to wire that up.

[Susanoo]

Alright bare with me if this has been said, cause I did not read all the replies to this. As far as the TPS, your car should almost die, or die for sure if you disconnect the TPS. That and the IAT sound like wiring issues. When I did the second b-swap I had a similar issue with some sensors. Ended up running wires directly from the ecu out my window and right to the sensor. Helped me to track down a short in part of the "factory" harness I used. You have 3 options with the ELD, 1) swap in an obd1 fusebox 2)chip the ecu and turn it off 3)find a Jdm obd1 ecu since they do not use ELDs. You can also disable the o2 sensor if you don't want to wire that up.


Im about to probe the voltages for TPS at all the connection points next to the ECU. Im also looking for someone local that can reburn my chip with ELD and O2 disabled at least for testing purposes since so many people have suggested it, If I cant find someone local I'll get someone else on ebay to do it for 20 bucks.

Maybe at some point I'll swap in a newer fuse box but I dont feel like doing all that. It would be easier if you could just pull the ELD out.

I also took the cat off and it didnt make much difference, cant remember if I mentioned that or not.

[Susanoo]

Alright so I probed some sensors and checked some wires for continuity and things seem fine. O2 has a solid connection from a to b.
Voltages at cold, not running...as read from the ECU side

TPS - .50
IAT - 3.17
ECT -3.20
Map - 2.99 (engine off)

[Legend_master]

I know it's a pain in the ass, but try bypassing the wires completely. During testing my shorted wires were showing proper numbers due to them splicing with another wire. Once I tried to run the car, it would give me a cel. Since it is only 3 wires, it should not take to long.

[A18A]

a bit late on the ELD thing, but in its place you can wire a IMA sensor (or a TPS, probably turned around halfway) in its place to the ECU to trick it into thinking it actually has an ELD. that got rid of my ELD error when i did my h22 swap :D

[Susanoo]

I know it's a pain in the ass, but try bypassing the wires completely. During testing my shorted wires were showing proper numbers due to them splicing with another wire. Once I tried to run the car, it would give me a cel. Since it is only 3 wires, it should not take to long.

Well no it wouldnt take long but what keeps bugging me is that I never had a tps code after fi conversion...even with sg2 being misconnected. I'll try it though and see what happens. Maybe I just have a couple bad sensors. They are just jy parts after all.


a bit late on the ELD thing, but in its place you can wire a IMA sensor (or a TPS, probably turned around halfway) in its place to the ECU to trick it into thinking it actually has an ELD. that got rid of my ELD error when i did my h22 swap :D

I've got a potentiometer laying around but I'd rather wire one in. I was reading last night about the IACV and all sorts of sensors play a role in how far it opens and closes. Brake and clutch switches, eld, ect, etc. I would rather tear an eld out but for now I think I'll get a chip with it disabled. However while waiting I do have a spare tps I could trick the ecu with.

[Susanoo]

Okay so its been a while but I messed around some more and I've got a new TPS on there with .50 on the red, 5 on the yellow and nothing on ground. The code 7 is gone and it seems like it might be better however after letting it warm up, shutting it off and rechecking the codes....code 6 an 10 are still there...even after swapping for my old IAT sensor...I've got a LLT replacement on the ECT from autozone so i'll try that again since finding the misconnected SG2.

[Oldblueaccord]

I guess thats just how honda works...its not important so lets make the engine run like shit anyway -_- The only way I can disable it is to have yet another chip burned disabling the ELD. I have a copy of crome free but I havent figured everything out yet and I have no way of burning a rom anyway.

I do understand theres a limited number of people but OBD1 is simple...ITS OBD1! The only difference between my obd1 and a teg that comes with obd1, for example, is the wiring and how the wires are routed. Course, yes, 4 wire O2 is usually found on obd1 but I dont have one. Simply put, even though all this shit was done by me and its not exactly like someone elses. People on here have a general understanding of things and I really dont care if things are thrown at me at this point cause I cant figure it out and I've already thrown over 500 dollars into it THIS month alone.

elpuma, dont you run the original O2 sensor??? I followed your build and guide closer then anyone and straight copied your pinout. Only difference is I used the old EGR signal wire for the ICM signal to aid in wire tucking.



The blue I put on the negative post of the coil, the black goes to the negative of the coil and the black/yellow goes to the positive of the coil...as I read on here..



Look dude I didnt know there were multiple issues okay? I fix one and find another, what the hell do you want me to say? sorry? All I can say is that you'll have to put it together in your head and compare everything I've done with what you know could be wrong now. I fixed all the sensor issues when I repaired SG2. Only the ECT was connected to the ECU properly.

What do you mean by a way to read all the data at once??

I do find their help useful, I do...especially 89T and elpuma, I recognize their expertise over many other peoples because they stay more active here then anyone i've ever seen.

http://honda-tech.com/showthread.php?t=2873474

Might help with the eld code. I dont fully understand the eld code i would think a 12-14v signal would be enough to satisfy it.

Also since you have removed your distributor a few times i would double check it right.

Wp

[Susanoo]

http://honda-tech.com/showthread.php?t=2873474

Might help with the eld code. I dont fully understand the eld code i would think a 12-14v signal would be enough to satisfy it.

Also since you have removed your distributor a few times i would double check it right.

Wp

What do you mean check it right??

Sorry but I have no idea how that works with the ELD bypass...I dont wanna have to flip a switch all the time either and by the sound of it I would have to since Im always blasting music and having to turn it up and down. I would rather the ECU always be in control of that...Right now I just dont have the spare cash to get a chip made with the ELD disabled...I thought about tearing apart an obd1 fusebox for the ELD but I have no idea where it is...I just understand its IN it as in PART of it somehow. So it may be best to first understand how ELD works so I guess i'll look around via google.

EDIT: I looked around for info on the ELD and I can see theres really no way to pull it out and I would have to swap in an OBD1 fusebox which im not ready to get into...SO I guess Im gonna look into this bypass more since it apparently makes the code go away and just leave it in "ECU mode"...

EDIT:All codes gone at the present moment except for code 14, Idle Air Control, and 20. There is something wrong with the IACV because for some reason its getting 12v constant with the key on so im gonna look further into this....

[Oldblueaccord]

What do you mean check it right??

Sorry but I have no idea how that works with the ELD bypass...I dont wanna have to flip a switch all the time either and by the sound of it I would have to since Im always blasting music and having to turn it up and down. I would rather the ECU always be in control of that...Right now I just dont have the spare cash to get a chip made with the ELD disabled...I thought about tearing apart an obd1 fusebox for the ELD but I have no idea where it is...I just understand its IN it as in PART of it somehow. So it may be best to first understand how ELD works so I guess i'll look around via google.

EDIT: I looked around for info on the ELD and I can see theres really no way to pull it out and I would have to swap in an OBD1 fusebox which im not ready to get into...SO I guess Im gonna look into this bypass more since it apparently makes the code go away and just leave it in "ECU mode"...

EDIT:All codes gone at the present moment except for code 14, Idle Air Control, and 20. There is something wrong with the IACV because for some reason its getting 12v constant with the key on so im gonna look further into this....

rest of the ELD thread.

http://forum.sounddomain.com/ubbthreads.php/ubb/showflat/Number/1806841/page/0/fpart/2

I was thinking this would be a cheap way to get rid of one more code with out getting a chip burned.


I meant, with your erratic running, I would make sure the distributor is properly installed and timed up. I would think you would have to jump out the OBD1 plug to set the base timing.


wp

[Susanoo]

rest of the ELD thread.

http://forum.sounddomain.com/ubbthreads.php/ubb/showflat/Number/1806841/page/0/fpart/2

I was thinking this would be a cheap way to get rid of one more code with out getting a chip burned.


I meant, with your erratic running, I would make sure the distributor is properly installed and timed up. I would think you would have to jump out the OBD1 plug to set the base timing.


wp

I read the thread from start to finish and I guess I'll just build that circuit but in place of the ELD i'll need a resister to set voltage at around 2.9 to be sure it goes back to low mode and not just like "where the hell did the sensor go" and throw a code. Right now im trying to figure out how many ohms and for the life of me I cant remember how the hell to do the calculation.

As far as timing I need a timing light but yea you have to ground the service check.

EDIT: This might take a while because I'll have to sit here and figure out where these wires come from that go to the ELD....But also I dont fully understand how this guys circuit works so I cant really safely or accurately redesign it for use WITHOUT an ELD....So im also not quite sure what you were expecting me to do with that thread....I need my high output mode for use with a sound system....disabling the ELD doesnt seem like the best choice anymore.

[cygnus x-1]

The ELD thing got me curious so I googled around a bit. The ELD sensor itself is not just a simple resistor. It's a very low ohm value resistor (current shunt) plus an amplifier circuit. The majority of the vehicles electrical current load flows though the current shunt and creates a very small voltage in proportion to the current draw. This small voltage is then amplified and sent to the ECU so it can decide to kick up the alternator output if the current load gets too high (or reduce the output if the load is low). If you really wanted to use an ELD sensor it would be easy enough to get one from a junkyard. See writeup here:

http://www.stevemeadedesigns.com/board/topic/139844-how-to-eld-bypass-for-honda-civicaccordfit/

However, I don't think you really even need to go to that much trouble. What that bypass is actually doing, is switching the ELD input on the ECU between the ELD sensor and an 820 ohm resistor to ground. So if you just want a permanent ELD bypass, all you need to do is connect an 820 ohm resistor from the ECU ELD pin to ground. Now I'm assuming you don't have an ECU controlled alternator anyway so there is no need to worry about that end of it (not having sufficient alternator output I mean).


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[Susanoo]

The ELD thing got me curious so I googled around a bit. The ELD sensor itself is not just a simple resistor. It's a very low ohm value resistor (current shunt) plus an amplifier circuit. The majority of the vehicles electrical current load flows though the current shunt and creates a very small voltage in proportion to the current draw. This small voltage is then amplified and sent to the ECU so it can decide to kick up the alternator output if the current load gets too high (or reduce the output if the load is low). If you really wanted to use an ELD sensor it would be easy enough to get one from a junkyard. See writeup here:

http://www.stevemeadedesigns.com/board/topic/139844-how-to-eld-bypass-for-honda-civicaccordfit/

However, I don't think you really even need to go to that much trouble. What that bypass is actually doing, is switching the ELD input on the ECU between the ELD sensor and an 820 ohm resistor to ground. So if you just want a permanent ELD bypass, all you need to do is connect an 820 ohm resistor from the ECU ELD pin to ground. Now I'm assuming you don't have an ECU controlled alternator anyway so there is no need to worry about that end of it (not having sufficient alternator output I mean).


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Thank you for your reply sir. But what I was thinking was some way to just flip from high to low and not even worry about an ELD. However you mention your assuming I dont have an ECU controlled alt...I've got the 4th gen alternator...I dont know if thats ECU controlled or not but through my research theres a pin that gets grounded to activate HO mode.

[cygnus x-1]

Thank you for your reply sir. But what I was thinking was some way to just flip from high to low and not even worry about an ELD. However you mention your assuming I dont have an ECU controlled alt...I've got the 4th gen alternator...I dont know if thats ECU controlled or not but through my research theres a pin that gets grounded to activate HO mode.

Oh, ok. I was thinking about how you would fool the ECU to get rid of the ELD code without having to rechip. That would just require you put that 820ohm resistor from the ECU ELD pin to ground. No switching required.

As far as the alternator, if simply grounding a pin increases the output, then yeah, all you need is a switch from that pin to ground. This shouldn't be needed just to get the car to start though.


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[Oldblueaccord]

I read the thread from start to finish and I guess I'll just build that circuit but in place of the ELD i'll need a resister to set voltage at around 2.9 to be sure it goes back to low mode and not just like "where the hell did the sensor go" and throw a code. Right now im trying to figure out how many ohms and for the life of me I cant remember how the hell to do the calculation.

As far as timing I need a timing light but yea you have to ground the service check.

EDIT: This might take a while because I'll have to sit here and figure out where these wires come from that go to the ELD....But also I dont fully understand how this guys circuit works so I cant really safely or accurately redesign it for use WITHOUT an ELD....So im also not quite sure what you were expecting me to do with that thread....I need my high output mode for use with a sound system....disabling the ELD doesnt seem like the best choice anymore.


Im going to show my age a little bit here but....


Since you need this car I would ditch the sound system until its running real well and then add that back into the mix.


wp

[Susanoo]

Oh, ok. I was thinking about how you would fool the ECU to get rid of the ELD code without having to rechip. That would just require you put that 820ohm resistor from the ECU ELD pin to ground. No switching required.

As far as the alternator, if simply grounding a pin increases the output, then yeah, all you need is a switch from that pin to ground. This shouldn't be needed just to get the car to start though.


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Oh the car starts and runs right now...however I still have the code 20 last I checked. I just wanna have a switch so one position is the 820 ohm for the high output and whatever ohm for the low output. I cant just have it run HO all the time, the alt will wear out much much faster. Im not 100% on that pin grounding thing either and im not sure thats the right way to go about it...

Im also looking at that diagram again and just placing an 820 ohm resister to ground from the ELD pin on the ecu, I dont think that will do anything....I could be misinterpreting the diagram and how this relay works but It seems like either way its using voltage from the ELD that, if I understand it right, the ELD generates itself..am I wrong?


Im going to show my age a little bit here but....


Since you need this car I would ditch the sound system until its running real well and then add that back into the mix.


wp

The amp and all that arent connected to power right now.

[cygnus x-1]

Oh the car starts and runs right now...however I still have the code 20 last I checked. I just wanna have a switch so one position is the 820 ohm for the high output and whatever ohm for the low output. I cant just have it run HO all the time, the alt will wear out much much faster. Im not 100% on that pin grounding thing either and im not sure thats the right way to go about it...

I googled around some more and it appears to me that the purpose of the ELD system is to increase fuel economy during periods of light electrical load. And that's really it. The idea that having the alternator in high output mode all the time will make it wear out faster, doesn't make much sense to me. Theoretically it might make it wear out faster, but it would be silly of Honda to design the system such that the alternator wouldn't still last a reasonable amount of time even if operated in HO mode all the time. And by reasonable amount of time, I mean 100,000+ miles. So given that, if it were me I would use the resistor to keep the ECU from throwing the code, and fix the alternator to run in HO mode all the time and be done with it.

Now, if you still want to have a switch to control HO mode, probably the most straightforward way to do it is to leave the ECU to alternator wiring as is (stock) and find a way simulate the ELD. More below...



Im also looking at that diagram again and just placing an 820 ohm resister to ground from the ELD pin on the ecu, I dont think that will do anything....I could be misinterpreting the diagram and how this relay works but It seems like either way its using voltage from the ELD that, if I understand it right, the ELD generates itself..am I wrong?

Pin 30 on the relay is the common pin (connects to the ECU input). Pin 87a is the normally closed pin (connected to the ELD output). In the normal state (relay not activated) pin 30 and 87a are connected together, so the output of the ELD is routed to the input on the ECU. Pin 87 is the normally open pin (connected to the 820 ohm resistor). When the relay is activated the common pin (30) switches over to pin 87 instead of 87a. So now the output of the 820 ohm resistor is routed to the ECU input, and HO mode is activated. So that's the bypass circuit.

In your case you don't have an ELD at all, so we need to find a way to simulate that. Back to google and found this:

http://forums.tunedtech.ca/f21/hondas-eld-bypass-1890.html

The ELD gives information to the PCM with a DC voltage between 1.1-5 VDC. The higher the number, the lower the load, and vice versa. So when the sensing voltage stays above 2.5-2.8 VDC, the PCM tells the alternator to turn off.
When the ELD sensing voltage decreases to around 2.1 VDC or lower, this tells the PWM that the ignition load is high, so the alternator kicks back on to full output and your voltage increases to >14 VDC.


So what that 820 ohm resistor to ground is doing, is pulling the ECU input voltage below 2.1V. To make the ECU switch the alternator to low output mode you need to bring the input pin up to 3-5V. Depending on what type of input it is (if it has an internal pullup resistor or not), it may be sufficient to simply leave it unconnected and it will stay high on it's own, although this is probably not the case given that it throws a code when disconnected. The easiest thing to do would be to find a 5V output on the ECU and switch the 820 ohm resistor to that instead of ground. If you can't find a 5V source, you could use a 12V source and make up a voltage divider with a couple more resistors. A 5V source is safer since it eliminates the possibility of burning out the input with an overvoltage. I can work out the resistors for a divider if you need to go that way.



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[Susanoo]

Yes, thats the purpose exactly and if given the opportunity to design the system with fuel economy as an option, I would prefer to keep it an option. It makes sense actually, operating at high output mode all the time will place a slightly bigger strain on the alternator itself and all the fun little electronics inside it such as the voltage regulator. I didnt go real cheap with my alternator either, I got a "new" alternator from a local shop that replaces everything with denso parts. I Just dont wanna take the risk and I want the fuel economy option.

However about the ELD and the bypass, I read through that stuff last night but the way you explained it is a little simplified for me. So I understand it all now. However, 820 ohms will no longer serve the purpose as I understand it, if we're to design this circuit around 5 volts then we will also need to recalculate how many ohms for the two separate target voltages. Lets say 1.8 VDC and 2.8 VDC.

[cygnus x-1]

Yes, thats the purpose exactly and if given the opportunity to design the system with fuel economy as an option, I would prefer to keep it an option. It makes sense actually, operating at high output mode all the time will place a slightly bigger strain on the alternator itself and all the fun little electronics inside it such as the voltage regulator. I didnt go real cheap with my alternator either, I got a "new" alternator from a local shop that replaces everything with denso parts. I Just dont wanna take the risk and I want the fuel economy option.

I agree, the option for increased fuel mileage is nice. I wonder how much difference it actually makes?




However about the ELD and the bypass, I read through that stuff last night but the way you explained it is a little simplified for me. So I understand it all now. However, 820 ohms will no longer serve the purpose as I understand it, if we're to design this circuit around 5 volts then we will also need to recalculate how many ohms for the two separate target voltages. Lets say 1.8 VDC and 2.8 VDC.


The 820 ohms would still be correct for high output mode since it just goes to ground (ELD ground though, not chassis ground), which is by definition 0V. The voltage at the ECU input pin itself won't be exactly 0V with the 820 ohm resistor connected, it depends on what type of input it is and what it's internal impedance is. The 820 ohm resistor is really there as a current limiter to prevent overloading the input. Otherwise you could just connect it directly to ground without the resistor (in reality you probably could and it would be just fine, but adding a resistor is a good safety). Anyway, the point is the 820 ohm resistor is still ok for HO mode.

For low output mode, you need to get the ECU input pin voltage into the range of 3-5V. If you have a 5V source available, the simplest way to do this is to connect the input pin directly to the 5V source. However it's a good idea to have a resistor there as a current limiter, so (again) the 820 ohm resistor would serve that purpose. Just as before, the actual voltage measured at the input pin (with resistor connected) will depend on it's type and impedance, but for sure it will be a little less than what the source voltage is. That's why it's best to use a source voltage of 5V.

If you need to use a 12V source, it gets more involved because now you need to make a voltage divider that will hold the input pin voltage to the required range (3-5V). That's easy enough to do but there is more risk of frying the ECU input if you make a mistake.


So before we go on, I would ask two questions. What is the supply voltage to the stock ELD sensor (5V or 12V)? Are there any other ECU outputs that supply 5V? (like for power to other sensors)
I'll dig around and see what I can find but if someone else knows the answer to these it would be helpful.


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[Susanoo]

The 820 ohms would still be correct for high output mode since it just goes to ground (ELD ground though, not chassis ground), which is by definition 0V. The voltage at the ECU input pin itself won't be exactly 0V with the 820 ohm resistor connected, it depends on what type of input it is and what it's internal impedance is. The 820 ohm resistor is really there as a current limiter to prevent overloading the input. Otherwise you could just connect it directly to ground without the resistor (in reality you probably could and it would be just fine, but adding a resistor is a good safety). Anyway, the point is the 820 ohm resistor is still ok for HO mode.


Okay so I'm pretty lost at this point...If the ELD input is expecting voltage...how does connecting a resister between ELD ground and ELD input result in a little over 0 volts?...Perhaps I misunderstand how the ECU inputs work...


So before we go on, I would ask two questions. What is the supply voltage to the stock ELD sensor (5V or 12V)? Are there any other ECU outputs that supply 5V? (like for power to other sensors)
I'll dig around and see what I can find but if someone else knows the answer to these it would be helpful.


I dont know what the supply voltage is to the ELD sensor...I've been completely unable to find a diagram for it using mid 90's service manuals for civics since, as I understand it, the P06 comes from a 95 civic. I assumed it would be my best bet to find out how its tied into the wiring. I dont know about any alternate 5 volt feeds...I was going to tie into the wiring just like an OBD1 honda would have it to keep things close to stock wiring diagrams.

[cygnus x-1]

Okay so I'm pretty lost at this point...If the ELD input is expecting voltage...how does connecting a resister between ELD ground and ELD input result in a little over 0 volts?...Perhaps I misunderstand how the ECU inputs work...

Well, I've been digging into this a little more and it looks like the ELD input is actually an analog input where I was thinking more like it was a digital input. From my research so far it looks like the ELD input is commonly used as an input for wideband O2 sensors, but to do that you have to cut the two pull up/pull down resistors inside the ECU. The resistors are important because they strongly influence the voltage on the ELD input and determine what the external resistors need to be to enable the alternator output modes. So far I have the values of the internal resistors but I'm not positive on what they are connected to. I have a best guess based on how these types of circuits generally work but the numbers aren't matching up with the voltages measured in that ELD bypass thread here:

http://www.hondaaccordforum.com/forum/audio-visual-electronics-10/honda-electrical-load-detection-eld-bypass-32726/


I'm wondering if you could take a measurement for me? Could you measure the voltage on the ELD input pin of your ECU with the ignition on and the engine not running? Make sure there is nothing connected to the input pin except the meter. Also, are you using a digital voltmeter or one with a needle?




I dont know what the supply voltage is to the ELD sensor...I've been completely unable to find a diagram for it using mid 90's service manuals for civics since, as I understand it, the P06 comes from a 95 civic. I assumed it would be my best bet to find out how its tied into the wiring. I dont know about any alternate 5 volt feeds...I was going to tie into the wiring just like an OBD1 honda would have it to keep things close to stock wiring diagrams.

Now that I have a better understanding (I think) of the ELD input, it looks like you may not need an external voltage source if the input has a pull up resistor already. It may be sufficient to just use two different resistors both connected to ground. One would be for high output and one for low. The trick is to figure out what those resistors should be.


So you have resistors on hand now?


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[Susanoo]

I'm wondering if you could take a measurement for me? Could you measure the voltage on the ELD input pin of your ECU with the ignition on and the engine not running? Make sure there is nothing connected to the input pin except the meter. Also, are you using a digital voltmeter or one with a needle?

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I'm using a digital volt meter and right now the ELD is pinned through to the OBD0 side where there is no wire. I'll have to add one in to complete all this but no big deal. I'll edit this in a few minutes with the results.

EDIT: Well I have good news my friend, 4.54 VDC was found at the ELD pin off the ECU.




Now that I have a better understanding (I think) of the ELD input, it looks like you may not need an external voltage source if the input has a pull up resistor already. It may be sufficient to just use two different resistors both connected to ground. One would be for high output and one for low. The trick is to figure out what those resistors should be.


So you have resistors on hand now?

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Yes I do, I've got like a multi-pack. I know how to figure out what one is what by the colors too.

[cygnus x-1]

Took me awhile to get back to this, sorry about that.




I'm using a digital volt meter

The reason I asked about the type of meter is because the old needle type meters have a low input impedance and can sometimes affect the circuit your trying to probe. Digital meters have a really high impedance and have no significant effect on the circuit.




EDIT: Well I have good news my friend, 4.54 VDC was found at the ELD pin off the ECU.

That's exactly what I was expecting, but until just now I couldn't make the numbers work out for the 820 ohm resistor. The error was that I was assuming the reference for the internal voltage divider was a constant voltage, when it's actually a constant current (of 4.5mA, or 0.0045A).

So if you want the voltage on the ELD pin to be say 3.3V (indicating low load, and therefore low alternator output), you need a resistor value of 2750 ohms. The closest standard value to that will be 2700, which is red-purple-red. Connecting this one to ground will put the alternator in low output mode. The switching circuit will be exactly the same, except that now pin 87a on the relay will connect to the 2700 ohm resistor instead of the ELD sensor.


I can explain the (ECUs) divider circuit and show how I worked out the values later if you like.


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