OBD-1 Harness Questions...

[2drSE-i]

Alright, what ive got here is the PJ0 and OBD-1 ECU pinouts, and i went through and made a chart showing both of their pinouts, and another chart that shows what OBD-1 pins correspond with OBD0 pins. Ive got around 10 wires that i cant figure out. This is me, asking for help.


Note: This is a general OBD-1 ECU pinout, it lists VTEC, knock sensors, and IAB (for dual stage electronic solenoid intake manifolds). I will be running a P06 ECU (Non-VTEC, manual) so the VTEC and Automatic transmission values arent needed, but i wrote them in there just to have the information. I have everything i know highlighted in yellow, and everything i dont i left alone. Here are the files, i have them uploaded to mediafire.

URLS:

List of both OBD1 and OBD0 Pinouts: http://www.mediafire.com/?7k9cyimjazm

List of OBD1 pins that i have figured out: http://www.mediafire.com/?4ewxzuaji7d

Thanks for the help guys!

[stat1K]

ever look at this? http://www.honda-tech.com/zerothread?id=1319235&page=1

[2drSE-i]

nope but that answers a couple of my questions. Thanks man! ill redo my chart when i get home form school, see how many wires im left with unanswered.

[stat1K]

for sure... you can also pm lx-incredible if you'd like but he hasn't been on much lately... he has made at least two of these harnesses for the accord and one for my rex.

[Accordtheory]

he has made at least two of these harnesses for the accord and one for my rex.
I'd be curious to see the 3g ones. Are there any pics anywhere? Specifically curious about how the add on harness goes through the firewall. I did this on mine with a separate connector basically right at the firewall.
You also have to fag around with the vss circuit, if you don't want to get a problem with a stock ecu, or you can disable it with programming, but then you can't do certain things, like a different rev limit when launching vs when moving, etc.

I think the only things I didn't connect were the eld and p/s press switch, if my p75 even has that, I can't remember.

[stat1K]

i believe the p75 does have those but i don't have pics i've only seen the one he made for me as it's in my garage right now... i'm sure he'll get pics of it soon enough though.

[AccordB20A]

i made one up the other night using the OBD1 pinout and the JDM 86 gold top PH3 ecu pinout. looks hory but it works. i need an ECU now cause all i have is a p29 and it needs to be chipped.

http://imagehost.wohdog.sytes.net/1stOBD1/DSCF1447.JPG

dosoldering those plugs out lo the old ecu was a fucking cunt. and the OBD1 wires being so fucking short didnt help eirther. but it works and thats the main thing

[stat1K]

so you tested it and no codes?

[AccordB20A]

code 11. which is the IMA sensor which my car doesnt have so thats ok.

[2drSE-i]

ok somethings in that thread did not quite match what i have for pinouts, i assume because those pinouts are for b series motors and the one that i have is from a d series.

I have 3 unused wires on the OBD0 Side:
A8: Vacuum Control Solenoid
Wont need this, vacuum will be gone :kekeke:
C9: Atmosphere Pressure Sensor
Dont think this will be needed either, this isnt used in OBD-1 ECU's, right?
A17: Power Input
Not sure what this is about. The wire colors (White/yellow) Matches that of the Back up power switch on the OBD-1 side, but that doesnt necessarily mean anything.


On the OBD-1 Side, i have quite a few left overs, One for the Alt C Alternator (it lists something that we dont have wired in our ecu on the thread on HT), One for Intake Control Solenoid (lists FAS on HT, not sure what that is, but there is no reference to this on that thread). There are three wires that i will have to add, one for backup power, one for brake switch, and one for service check connector (DONT HAVE A CLUE...)

EGR Valve lift sensor (we dont have one) is an issue...
ECT Switch is just the fan switch right? that also needs a wire added...

The last is the ELD, which isnt in our ECU, so ill have to add a wire for that too

[EricW]

I don't have anything connected to A8, A17, or C9 on the obd0 side.

As for the ELD(electronic load detector) you are going to have to wire that one in or just disable it with software. You'll probably end up just disabling it with software. The ELD is located in the fuse box of the obd1 cars.

[2drSE-i]

well like i said the first two are gonna be unneeded with the OBD-1 conversion in the first place. Its obvious to me that the OBD-1 ecu gets its power some other way, so A17 isnt needed either. Where is the ELD on our cars? i dont really want to eliminate any wires that are necessary, because i want to be able to run a stock ECU before i begin tuning, Just kinda eliminate multiple failure points by consolidating what i do.

[2drSE-i]

Alright well ive been working through this, without wiring the ELD, the ECU won't throw a code so its not really necessary. It would be nice to have it wired but i can live with it otherwise.

Other OBD-1 swaps use the A17 (Power Input on OBD0) for the D1 (Back up Power, which apparently isnt what i thought it was (reverse lights haha))

[stat1K]

haha @ reverse lights lol... but yeah the eld isn't really necessary from what i've seen. my car is actually throwing the eld code right now and it doesn't change anything.

[2drSE-i]

Alright so im down to a few wires.

ECT Switch:
This, i just need to run a wire from the fan switch to the ecu, right?
Alt C Alternator:
Am i going to need to swap harnesses for my alternator to charge correctly??
Intake Control Solenoid:
Im pretty sure this is empty on the P06, and is only for the H22. So i think that one ive eliminated as well.
Brake Switch:
?? got nothin here guys
Service Check Connector:
No clue here either...

Thanks for all the help guys!

[Accordtheory]

wtf does the eld do anyway? Pick the idle up when it detects droppping voltage?
I didn't have it connected with my p75. My idle was always fucked up, but I think that was due to the wrong iacv. My entire setup was pieced together from mostly unknown shit. I don't know where the majority of my little bs parts came from, year/model wise. However, all of them are being replaced, due to the vtec and turbo conversion. Without the eld, the ecu should just attain the target idle, and keep it there.
Fan switch, the 3g has it's own separate control for that, (box under the pass seat) the ecu doesn't need to do anything with it. (remember the stupid fan coming on after the car was parked? I'd get rid of that shit, it's the "extra" sensor on the water neck that triggers that)
Same with the charging system, I don't think the ecu affects that either. (back to that disconnected eld?) It might measure it, but I don't think it controls it. Not 100% sure though, but isn't it just 1 wire anyway?
intake control solenoid? gsr/h22 2 stage intake. Could be used to control the 88/89 3g 2 stage piece of shit..but why. That should be thrown in the trash.
Brake switch? Can't remember. What would that be needed for, the ecu doesn't run the cruise control or anything..wtf?
Service check connector..not the check engine wire, this wire when grounded makes the ecu go into diagnostic mode (where it flashes codes though the check engine light).

The speed sensor is the only thing that isn't just a straightforward connection. You need to modify the shape of the waveform that the ecu sees from the speedo output. I can't remember exactly how to do this, but it's easy with just a few parts from radio shack, I wrote a little how to somewhere on this site.

[2drSE-i]

the VSS guayanabo wrote a how to on with pics as well, pretty straightforward if you have some clue about what your doing (which you should if your attempting this)

The ELD detecs electrical load, which i guess could be useful if the circuit builds a load, but otherwise no.
Thanks for clearing up the Intake control, wasnt sure if it was the same as the IAB, which your saying it is. Our dual stage intake is controlled with vaccuum, theirs is electrical. Im sure we could hook up an electrical solenoid, but like you said it doesnt flow worth shit anyways.

Your saying the fan switch should just be left unwired? hoping that this isnt gonna throw a code... I knew our ecu didnt control it though.


On the other side of things, i dunno what IACV you used, alot of the civic guys are using our EACV mounted upside down to bypass the coolant lines in their Y8 manifolds. Goofy bastards haha.

[89T]

Bump, for the guy's doing the conversion on their own.

I am doing some research, prior to starting mine up. something i found PP...
Edit: never mind it does noteven begin to match Carotman's 88-89 pinout.

[89T]

service check connector: 2 wires 1 is a ground and the other is pin D04.

In other words short pin D04 to ground to check for cel codes.

[89T]

ever look at this? http://www.honda-tech.com/zerothread?id=1319235&page=1

I have an 89 lxi and I made my adapter harness using this pin-out. I just cross referenced it with Carotman's 88-89 pin-out.there seems to be about 14 issues and 8 question-ables. The group of dizzy wire's were included with the issues.

http://www.honda-tech.com/showthread.php?t=1319235

I am off to check this pin-out. (I'm board) I'll try and post somthing up tomarrow.

[LX-incredible]

Use any obd1 pinout and the carotman 88-89 accord pinout. There are several differences with the obd0 civic/integra pinouts, so don't bother.

[AccordEpicenter]

disable the ELD. Without an ELD input the ecu might not run alternator output high enough to keep the battery charged etc. I disabled VSS too so i dont worry about it, at least for now

[89T]

Use any obd1 pin-out and the carotman 88-89 accord pin-out. There are several differences with the obd0 civic/integra pin-outs, so don't bother.

I slowly figured that out. LOL! The main reason i went through the trouble was to prove or dis-prove one of the other threads on the board. Mainly the one that states that you only have to change the dizzy wires if you buy X harness.

It would be easier if i asked for the pin-out's from one of you guy's, but I wouldn't learn anything in the process.
I have found a pin out for the po6 that I am going to use.
If it doesn't work out I'll just buy one from you.

http://www.dodo-upgrades.nl/pinoutp06p28p30.htm


disable the ELD. Without an ELD input the ecu might not run alternator output high enough to keep the battery charged etc. I disabled VSS too so i don't worry about it, at least for now
Yea! I am not going to worry about the ELD either.
guaynabo(Sp) has a write up some where describing the vss fix.

[89T]

I have started a conversion pin-out based on the po6 pin-out above and at this point I am going over the obd1 harness to make sure everything is accounted for.
From pin-out to pin-out it is done. Now for all that remains + the extra inputs/outputs.

[LX-incredible]

Pinout looks fine to me. If not using it, you'll need to disable the ELD when you chip the ECU or use a PR4/P75. I wouldn't bother with the VSS unless you throw a code. Most haven't had an issue. Strugglebucket did the "VSS fix" with his conversion, and actually had to remove it to clear the code.

[89T]

hmm, good to know thanks.
Also i am running a aem wideband. So i disabled the stock O2 sensor in the management and wired it in on pin D14(input on the neptune). Doing that leaves both shielded O2 sensor wires. I trimmed them back in the harness and wired them to the obd1 dizzy.
I am gonna try to fire her up today, hopefully she runs. That's if i don't go fishing. LOL!

[AccordEpicenter]

I have the o2 sensor and closed loop disabled, as well as eld and vss and injector check and all that stuff disabled also. I did exactly as you did too jerry, used both old o2 sensor wires for the dizzy wiring. I only had to run 1 wire, so I used an old shielded RCA cable from an old audio setup i had, and cut the ends off. Worked great. Hopefully itll fire up ok...

[89T]

so i went out plugged it in, blew a fuse and went fishing to only catch every hungry mosquito at the lake.

[AccordEpicenter]

funny you had blown fuses, i had 2 blown fuses from god knows what issue before my car ran, i believe they were both under hood, one was the injector fuse and the other was the ecu fuse? I cant remember. They didnt blow a second time though. What was yours?

[89T]

alright , I fucked up put a wire in place where there were no corasponding wires! So I got a code 20. my bad.
done! no codes but she wont run well. I added a shit ton of fuel and still barly smell any fuel. I think i have a dizzy problem namly base timing, but at this point i am tired of fucking with it. The tag on my old hood said 12 deg +-2 that sound right?
heres the pin-out.
http://img684.imageshack.us/i/17872520.png/

Edit: d1 = a17 Sorry i forgot to add that to the pic

i'll get it.

[LX-incredible]

Set the timing at 15º BTDC with D4 grounded.

[89T]

LX-incredible, You're money! :)

she fired right up! time to get her done.