Wierd idle problem... missfiring?

[Hash_man_Se_i]

Lately I have been having a very wierd idle problem.

It has only been happening for about the past 2 months, but its wierd because it is intermetant (sp) and doesnt happen all the time.

ok, so here it goes...
Every once in a while, usually after a long drive, I will stop my car somewhere, like at the mall, at home, or something. And afterwards, when I get back in the car, usually after about 30minutes... I start the car, and it Idle's INSANELY rough. The idle seems to fluctuate up and down, lately only up and down about 200rpm, but before it was up and down a lot more, and the car would shake and shake.

Before it got to the point of almost stalling, and it scared me so I would turn off the car, get out and wait a while and come back, after trying a few more times. Then when I came back, it would usually work just fine.

Lately it hasn't been getting to the point of almost stalling, but it idles rough, at around 600rpm, and goes up and down a bit. But now when that happens, I can usually turn the car off, and if I start it up again a few minutes later, it runs fine.

Anyone have any clue of what could be wrong? I am out of ideas... Oh, and one last thing, which one of my friends pointed out the last time it did this; whenever it idles rough like that, if the dash lights are on, they seem to dim as the idle goes up and down.

Please help :help:

[Justin86]

well the dash light will dim evertime you start up the car. I kind of have the same problem but not as bad and it happens very little. Check your plugs, wires, distrubitor, and might want to change the fuel filter too. Try using higher octance gas for a while to see if it helps. I know that in my moms van if you don't put 91 or higher it will idle like crap.

[Hash_man_Se_i]

Ya, I just changes the fuel filter on the firewall a little while ago, only about 2 months ago... And its really wierd because it only happens every once in a while. I mean it will run fine for a few weeks, with no problems at all, and then it will start acting up.

[Justin86]

what about you spark, is that all good. I'm thinking it might be just some bad gas.

[Rex]

I've been having the same problem too... cant figure out what it is, it would be nice to know, even though it hardly ever happens.

[Hash_man_Se_i]

what about you spark, is that all good. I'm thinking it might be just some bad gas.


I really doubt its bad gas... I have been through about 10 tanks of gas or more since this started happening, and it still happens. I also thought it might be water in the gas at one point, so I threw in some gas line antifreeze, and it still happens.


I've been having the same problem too... cant figure out what it is, it would be nice to know, even though it hardly ever happens.

Finally, someone else with the same problem... i mean its not a good thing, but maybe together we can figure this out. lol... I am actually going to pull my car in to the garage today and check the ignition stuff... plugs, wires, cap, rotor. Maybe I will take my ignition control module in to work and test it... who knows, that could be the problem.

[Rex]

Well, i am guessing for me it isnt the plugs/wires/coil... their all new.... i've tried to figure out if there is something in particular that goes on, ie weather, time driving, etc, but i cant really seem to find anything.... although it only seems to happen when the car is warm... i guess i am really stumped on this one. i think mine might be a little worse then yours at times though, cause mine will usualy die when it does this.

[Hash_man_Se_i]

Mine would usually die, or close enough that i didnt want it too and I would shut off the car before it did.

And I dont know what I'm saying, because my plugs, wires, cap, rotor were replaced not even a year ago.

I am experiencing the same thing... it onyl happens when the car is warm, but I cant connect it to anything else. I thought it might be the cold weather, but it happens on warm days as well, and only when the car is warm... damn im confused.

Hey Rex, do you have msn? if so PM me, so we can try and figure this out.

[chomezy]

I have a somewhat similar problem myself, my car will idle somewhat rough when it starts and then about 20 seconds later it will go down to about 200 rpm, when the car warms up, it is fine though. I THINK my problem has to do with the fact that the rocker valve gasket has been leaking oil into my spark plugs for over a year, the guy before stripped the spark plug casing (lucky me). I would agree "Justin86" to check your spark plugs and ensure they appear in good condition. Otherwise I would guess that condensation from the engine being warmed is cause a bad idle, and when the car warms up, does the idle get better?

[chomezy]

If the idle does get better after it's warmed up. Just for testing reasons, put a blanket(old crappy one) over the engine after you shut off the car and take the blanket off before you start the car again and see if the car starts better. I realize this doesn't sound like the most intelligent idea, its an idea someone gave me. I'm not really that auto intelligent

[Hash_man_Se_i]

I would guess that condensation from the engine being warmed is cause a bad idle, and when the car warms up, does the idle get better?

Whenever this happens, the engine IS warm. It is usually after a long drive, then i will get out, and come back to the car and this happens.

Yesterday when it happened when I went to pay my ticket, I got back in the car, started it up, and because it was happening i decided to pop the hood and take a look... and when I did, I saw that the engine was shaking like crazy.. like when you start your car, it will shake, and it was like that, but the car was running, and the idle was staying around 600rpm, but going up and down about 100rpm.

[Justin86]

well I looked into my very handy service manual at the trouble shooting. "irregular idle" @ "after warming up" = (ECU)-faulty ECU. (INJECTOR)-open/short circuit, stuck injector. (FAST IDLE MECHANISM)-stuck air bypass valve. (CRANK ANGLE SENSOR)- open/short circuit, faulty sensor. (MANIFOLD ABSOLUTE PRESSURE SENSOR)-open/short circuit, faulty sensor, broken/disconnected hose. (IDLE CONTROL SYSTEM)-faulty solenoid valve. (OTHER)-check ignition system (sparks), and each injector. Possible to start by operating throttle? (stuck air bypass valve)
Have fun! :wave:

[Rex]

For mine i can rev the engine and it revs fine... i usually rev it to 1.5k and let it sit there for like 20 seconds... after that it is fine

[Hash_man_Se_i]

well I looked into my very handy service manual at the trouble shooting. "irregular idle" @ "after warming up" = (ECU)-faulty ECU. (INJECTOR)-open/short circuit, stuck injector. (FAST IDLE MECHANISM)-stuck air bypass valve. (CRANK ANGLE SENSOR)- open/short circuit, faulty sensor. (MANIFOLD ABSOLUTE PRESSURE SENSOR)-open/short circuit, faulty sensor, broken/disconnected hose. (IDLE CONTROL SYSTEM)-faulty solenoid valve. (OTHER)-check ignition system (sparks), and each injector. Possible to start by operating throttle? (stuck air bypass valve)
Have fun!

Hahahah, thanks... thats so many things it could be, but I guess its a nice start. I have a strange feeling it is something with an injector, but we'll see.

And Rex, I can rev mine fine as well, but as soon as I let off the throttle it starts idling rough again, but if I hold it around 2k for a minute or so, it sometimes stops.

Oh, and BTW, Justin86, what manual do you have that you are reading this in? it sounds like some very helpful information.

[Justin86]

They very expensive and hard to get Honda Service Manual. You might be able to get them on ebay for $50 and if the dealer still has them it will be even more. There is a reason why the chiltons and haynes manuals are so cheap, cause they are crap.

[FatDave]

They very expensive and hard to get Honda Service Manual. You might be able to get them on ebay for $50 and if the dealer still has them it will be even more. There is a reason why the chiltons and haynes manuals are so cheap, cause they are crap.
:huh: holy crap, i paid $5 for mine maybe i should take alittle better care of it

[danronian]

I would try cleaning the throttle body real well, check for ECU codes when it idles crappy, and also try using some gas line antifreeze additive. Does your gas cap hold pressure?

[Bioforge]

hmm, I would run some injector clean just for shits and giggles...It could just be that there is some "gum" build up in the injectors causeing it not to spray as well...possibly check your o2's, they could be going.

[Blkblurr]

I have the same problem with my 89 Accord SEi. I have had it for a couple of years and it happens every time I drive it on the interstate, shut it off and start it again a few minutes later. I'm sure it is heat related and I can eliminate the crank angle sensor as the cause because I have replaced my distributor during this time as well as both oxygen sensors and it did not help. I did not replace these items to try to fix this problem. It was for other problems. I can say that it does not bother me much because I can just run the engine at a higher rpm for a few seconds and it goes away. The engine shake is a result of rough idling.

[Bioforge]

hmm, heres an odd one, but it was an issue on my friends nissan...tighten all the engine mounts...when his got loose, it would seem to idle rough, but was just shaking alot.

[Blkblurr]

Mine is idling rough because the rpm's drop to around 200. I think it is heat build up in the engine after it stops causing the air/fuel mixture to be incorrect. Could be a sensor failing as well.

[MoonScryer]

They very expensive and hard to get Honda Service Manual. You might be able to get them on ebay for $50 and if the dealer still has them it will be even more. There is a reason why the chiltons and haynes manuals are so cheap, cause they are crap.


Ummm, you can go to any Honda dealership and order the shop manual and the electrical manual, at any time - same stuff they use. Helms Inc is the one who reprints it for them. It's the same price on the Helm Inc website as at the dealership, but I don't know if you have to pay shipping or not if you go through the dealership.

http://www.helminc.com Choose your make, year, and body style. It's an original looking manual w/ the supplements - usually on the seatbelt. Shop manual is $59; electrical manual - which looks like a bad xerox copy, but still worth it - is $39.

Easy huh?

[Hash_man_Se_i]

I would try cleaning the throttle body real well, check for ECU codes when it idles crappy, and also try using some gas line antifreeze additive. Does your gas cap hold pressure?

Had the whole upper intake and injectors cleaned a few weeks ago, and whenever the rough idling happens now, it seems to not be quite as rough, definately not to the point of stalling any more. I tried gas line antifreeze, and yes the gas cap holds pressure quite well.

And I really should check the ECU for codes, I have a feeling that could be the problem.

[TINBOAT]

Did you change the fuel filter ?, also, have you bled off the cooling system ?...The IAC could be bad or 'vapor locking' on the coolant side of things.

[1988starter]

I had that problem it turned out to be my fast idle valve was not closing all the way and my IAC was tring to compensate. Also on a side note Changing the oil also seemed to really help the situation (weird huh). It is all good not I got a fast idle that closes altho it is weird durring fast idle. Fortunately majestic honda is on it's way tih a new one.

[Hash_man_Se_i]

Idle air control valve hey? hmmm, maybe I will try replacing mine, better go in to work and price one out.

And when my upper intake was cleaned, I also had the oil changed and after that it seems to be quite a bit better.

[1988starter]

I have a extra IAC I pulled of a jy car looks in good shape I can let go for 30 other than that the cheapest I found them was like 130 at majestic honda

[1988starter]

there is a thread about the IAC/code 14 in the faq It tells about how to test it.

aww screw it this is what it says

--------------------------------------------------------------------------------

code 14, Electronic Air control valve (EACV)

1) turn ignition off. Remove #11 fuse in the under-hood relay box for 10 sec. to reset ECU. Start engine and observe "Check Engine" light. If light is off, problem is intermittent. Test drive and check again.
2) If light is on, turn ignition off. Disconnect EACV connector. Check resistance between the 2 connector terminals on valve.
3) Resistance should be 8-15 ohms. If not within specification, replace EACV. If resistance is within aspecification, proceed to next step
4)Check for continuity to ground on each EACV connector terminal. If continuity exists, replace EACV. If no continuity exists, turn ignition on. Connect volt meter between Black/Yellow (pos) and Black/Blue (neg) terminals.
5) Check for battery voltage. If no battery voltage exists, proceed to step 6. If battery voltage exists, disconnect connector from ECU and again check for battery voltage. If battery voltage still does not exist, substitute a known good ECU. If condition is rectified, replace original ECU. If battery voltage does exist, repair short between Black/Blue wire between ECU terminal A11 and EACV
6) If no battery voltage existed in step 5, measure voltage between ground and black/yellow terminal. If battery voltage now exists, proceed to step 7. If battery voltage still does does not exist, repair open Black/Yellow wire between fuse #1 and EACV
7)If battery voltage exists, turn ignition off. Reconnect EACV connector. Connect ECU test harness connector "A" to main wire side harness only. Turn ignition on. Using a voltmeter, measure voltage between connector terminals A11 (pos) and A18 (neg). If voltage does not exist, repair open between ECU terminal A11 and EACV
If battery voltage exists, connect and disconnect terminal A11 to A18. If EACV does not click when connector is connected and disconnected, replace EACV. If EACV clicks, substitiute a good ECU. If condition is rectified, replace original ECU
9) If none of the above works proceed to drive the fucking thing off a cliff

Thanks to Eric (POS carb)
__________________

[Blkblurr]

In the two years mine has been idling rough after running it on the interstate for a while then shuting it down and starting it again about 25 mins later, it has never prduced an ECU code.

[Rex]

Well, for me, it seemed that most of the problem was the iac.... got one from the wreckers, and it seemed to help alot, but the car still does it every now and then..... replacing the iac seemed to help it run alot better too

[Hash_man_Se_i]

Ya, my car has never thrown up and codes... that would just make things too easy now wouldn't it.


I have a extra IAC I pulled of a jy car looks in good shape I can let go for 30 other than that the cheapest I found them was like 130 at majestic honda


I work at an auto parts store, so I should be able to get one fairly cheap./

[1988starter]

That would be cool if you can get one I had a few places tem me that it was a honda only part so I had to go majestic honda.

[Hash_man_Se_i]

Ya, so far i may have to do that, I can't seem to find an aftermarket listing for it.

[88accordalltheway]

shat guies, mines doin the same thing. It just started this weekend, after i drove it alot. Im having my dad take it to his work so this guy can take a look at it, also my car has had a hesitation problem, like when i would step on the gas from an idle, the car would hesitate, then it would take off. I think these probs have somthing to do with the timing of the pistons. I also think the hesitation has somthing to do with air flow. After i get mycar back and hear what the guy tells me, ill tell you what the prob is, k guies, later
Kevin

[88accordalltheway]

had my car looked at today, no good news. when we got to the guys house, he heard my car, and hes like that dosent sound good. we poped the hood, and he started to play with the spark plugs and wires. Soon we found out that only 2 of my cilinders were fireing. he checked the valves, nothin wrong there. then he started to play with the air filter, he thought there might be a leak or somthing. he got this spray and sprayed the filter and carb, nothin. then he sprayed a little on the engine, right where the intake manifold and engine block meet, the spray fixed it for about 2 seconds, then it went back to chuging. He then told us that the intake manifold gasket was blown. I just though to my self, great, i really did it this time. The gasket is preety much in the middle of the engine, so its going to be an ass to replace, but the guy is gonna do it. He said that the reason for it blowing was either heavy acceleration or a backfire.(ill let you decide which one it is, just for reference, check out my user icon) Hes only gonna to charge $150 to fix it, guess i got really lucky. Ivew been really hard on this car, speed wise, i guess im gonna have to lay off now:( It was fun while it lasted but i dont want to blow another gasket.Heres jjsut another thong to be careful of, so be careful guies. see ya later

[FoX]

My car does this once in a while too. I have notice though on the guages i have installed that the fuel mixture will get real lean for a second when it starts running rough and the vacuum will bouch back and forth about 1 or 2 In.Hg. sometimes its just the vacuum bouncing and fuel mixture stays ideal. i think it has something to do with my cars map sensor though. i need to dig out my service manual and see what it says as far as testing map sensor.

[Blkblurr]

It would be great to get this solved because so many of us have it. Once this is solved we need to post the solution on this site. If we can get several of us that have this problem to perform the same fix we will have good data to back it up. What do you guys think?

[rocky2]

Take a mirror and look inside thottle body for carbon buildup. It cuts airflow down when its hot also preheats air mixture which is bad. Either take off or attack it with cleaners

[Ducati]

Hey, Hash Man - Are you the same Hash Man who was on Beyond.ca (where I was recently banned from for calling rage2 a Site Nazi who had to buy a website in order to acquire a group of captives who would listen to his grandiose bullshit)

Anyhoo - my girlfriends 86 also shakes at idle, so I hit upon this most excellent and helpful thread. I wonder if replacing plugs and wires would be a waste of money or what? Perhaps there are other things I should look at first to solve the problem?

I have obviously been driving diesels too long, and have forgotten all of my decades ago mechanical learning, and now need to elicit the help of the young uns'.

Peace!

[Justin86]

Take a mirror and look inside thottle body for carbon buildup. It cuts airflow down when its hot also preheats air mixture which is bad. Either take off or attack it with cleaners
oh yea that can be a real big problem. I got a head to do some work on it and this crap was cake on the head intake side and all over the intake manifold. It was like a think gel/grease or something and was not pretty at all. :sadwave:

[Ducati]

oh yea that can be a real big problem. I got a head to do some work on it and this crap was cake on the head intake side and all over the intake manifold. It was like a think gel/grease or something and was not pretty at all. :sadwave:

I wonder if spraying in Combustion Chamber Cleaner every day for several days would dislodge the gunk that is inevitably forming inside the manifold of her car? We just bought it last weekend. It has 175000 kilometers on it, and is an otherwise well maintained one-owner car. The owners say they did not use "snake oils" like these cleaners.
I use fuel system cleaner in my own vehicles, and have for many years, with no adverse results...and no shaking.

[Rex]

Hmm, well, i was having the whole idle problem at random starts... it seems that since i adjusted my valves, it has gotten much, much better... it hasnt done the crazy idle at start, and it idles smooth, and hell, has power.

-Matt

[Ducati]

Hmm, well, i was having the whole idle problem at random starts... it seems that since i adjusted my valves, it has gotten much, much better... it hasnt done the crazy idle at start, and it idles smooth, and hell, has power.

-Matt
Aha! Another fellow Canajun, eh? Good - then you are familiar with the Canajun Peso.
I have faaarr too much work to do of my own and am not particularily inclined to do too much work on the girlfriends Accord unless I absolutely have to. That being said, what is involved in a valve adjustment? Is it just a straight-forward matter of finding TDC and using a wrench and feeler gauge to adjust the clearances between a rocker on each stroke, against a cam lobe? There are two smaller intake valves and one larger exhaust valve, I am guessing.
I have never cracked the binding of a Honda service and repair manual in my life.
If I get lazy (and its her money anyway) what does a valve adjustment cost at a local garage in Ontariario?

[Hash_man_Se_i]

Hey, Hash Man - Are you the same Hash Man who was on Beyond.ca (where I was recently banned from for calling rage2 a Site Nazi who had to buy a website in order to acquire a group of captives who would listen to his grandiose bullshit)

Anyhoo - my girlfriends 86 also shakes at idle, so I hit upon this most excellent and helpful thread. I wonder if replacing plugs and wires would be a waste of money or what? Perhaps there are other things I should look at first to solve the problem?


Yup. thats me.

I am still trying to figure out this idle problem, but I have been lucky enough that it has not happened in probably close to three weeks now, im stoked.

I am going to see what happens in the next little while, and if it happens again, I am going to get a coolant flush (which i need anyways) and try changing my IAC.
I had the car in to honda about a week ago, and they couldnt seem to get anything to happen to the car... so I dunno, and they have no clue what this could be either.

[Frankfurt812]

i am having the same problem but mine will sometime die if i do not give it gas immediately...i was given a solution that i have not tried yet that is exact opposite of what u all are saying. the ect sensor is on the thermostat housing closest to the head. it supposedly sends signals to the ecm on the motor temp...when the motor is cold it uses more fuel when starting than a warm motor. if the sensor is faulty it will send signals that a warm motor is cold and dumps more fuel causing it to "flood" itself. thats what i was told and actually it seems really logical i am going to try it next weekend you can get it at autozone for a little more than 30 dollars.

[Hash_man_Se_i]

That actually makes a lot of sense, I was told by a mechanic that I talked to to look in to the temp sensor on the block seeign as it obviously is directly related to engine temperature.... Lucky for me though, i have not had this happen in about a month now, which is nice to know... and I must say the accord hasnt run this well in a long time since i just cleaned the K&N filter.