suds1485

ok i have a 2001 civic ex coupe. it has 131000 miles on it i got it like 3 weeks ago from my sister. over the weekend i did my timing belt, water pump, oil pump, and valve cover gasket. everything went well/normal, as ive done this job before just on an h23. so now that its all done i go to start it and it starts fine. i drove it down the block and i felt it was idling a lil low. my dad said it was fine and not to worry about it. on Tuesday i drove to work and it actually stalled. restarted it an it seemed fine i drove to work with put further incident. than id did pretty much the same thing when i was leaving work. no what could be my problem?
to sum it up:
1. NO CHECK ENGINE LIGHT.
2.WHEN COLD I FEEL IT IDLES A LIL TOO LOW.
3.AS IT WARMING UP AROUND THE SAME AMOUNT OF TIME ITS IDLE DROPS AND ULTIMATELY THE CAR STALLS .
4. WHEN ITS UP TO NORMAL OPERATING TEMP IT RUNS FINE AND THE IDLE IS FINE.
please help and thanks in advance

lazlong

Had the same problem. Do the idle re-learn procedure:

1. Make sure all electrical items are off.

2. Start the engine and hold it at 3,000rpm without load until the radiator fan comes on, or until the engine coolant temp reaches 194F.

3. Let the engine idle for about 5 minutes with the throttle fully closed.

* If the radiator fan comes on, do not include it's running time in the 5 minutes.

suds1485

i did that and it didn't fix it. i think i had air in the cooling system. so i just finished the annoying process of bleeding it. hopefully it fixes it. if not ill do the relearn again.

It Wasn't Me

Interesting. . I was actually going to suggest the same thing. (idle relearn)


Have you cleaned the IACV or Throttle Body? You didn't happen to mess with the throttle-stop screw, did you? Some people mistake it as an idle adjustment screw.

suds1485

no didnt clean the iacv yet. or mess with any settings. i figured let me try the other things before taking more apart.

suds1485

so i bled the coolant system and did the idle relearn. it still does it. i guess ill have to clean the iacv and throttle body. but my question is why would this start all of a sudden.

It Wasn't Me

None of this was happening prior to doing the work on it?

Does it do these things every single time you drive the car?

While it's cold, where is the idle at? (RPM)

Once it's warm, where is the idle at? (RPM)


It almost sounds like an intermittent fuel delivery issue, but without any codes being thrown, it's a matter of guess-work.

suds1485

prior to the work the car ran fine.
so far it has done it every time. but when t warms up its fine.
cold idle is at 1000-1100 ish
warm idle is at like 700 assuming the first line on the tach is 500
when it at normal operating temp car runs perfectly.

It Wasn't Me

Bizarre. The idle sounds about right in both cases. Not sure why it would be acting this way "out of the blue."

The only thing I can really suggest is to let the car warm up before driving it.


I'd definitely clean the IACV and throttle body. Especially if it's never been done.

suds1485

im gonna clean them on sat. its funny my dad said the same thing about letting it warm up. well ill let you know how i make out on sat.

suds1485

ok here is an update of exactly what is happening.
when i first start the car like when im leaving work it idles fine. it also idles fine when im at normal operating temp, but when it warming up about half way between the bottom of the gauge and normal operating temp it starts to run really rough and buck like its about to stall but it catches so it stays running. when it is doing this if i hit the gas to kick up the rpms it hesitates not helping at all. i also noticed when im decelerating the idle drops but than kicks up again and than drops to normal.
so im thinking it could be either a dirty iacv or rac what ever honda calls it in this car, or still air in the cooling system. sorry for being a "post *****" but any input will greatly appreciated

Tico Loco

Strange but something is wrong. A fuel pump problem normaly gets worst after 5 or 10 minutes, so it do not look like fuel pump and fuel regulator normaly fails under hard acceleration. Recheck your timing and timnig belt, it could be one teeth advance or retard.

Also check for very old spark plug cables, spark plugs seems fine.

Test the car without A/C and with A/C to see if their is any change.

suds1485

^idle is 700 when warm around 1100 maybe more when cold on an 85-90 degree day. with out any accessories on. also to my knowledge the throttle body and iac have never been cleaned

It Wasn't Me

He didn't say the idle was 700 when it was cold, only after it's warm.

If the timing was off by a tooth, the car will not stay running, if it even starts.

And we don't have spark plug cables.



It's extremely weird, and I'm honestly stumped. I'm sorry that I am unable to provide a quick-fix answer for you.

jdmfreak1992

Clean the IACV first see if that helps.

wickedbautista

sounds like you just need to do a valve leash adjustment

It Wasn't Me

Gotta keep that leash tight, or them dogs will run wild on ya.


But, yeah, a valve adjustment would probably be a good idea considering the mileage on the car. I doubt it was ever done.

suds1485

^i thought about that. but it too intermittent for me to think valves. plus the valve train sounds good its nice and quiet. also when it was my sisters car she brought it to honda for most of the maintenance.
i also thought it might be the o2 sensor. it just sucks because i have no codes

It Wasn't Me

Hmm, considering that the car had 131k miles on it, and the timing belt and stuff hadn't been changed, which it should have 20-30k miles ago, one wonders what else had not been done.
Or had it already been changed, but you did it again anyway?


If the sensor was bad, the MIL would be on. (unless the cluster is malfunctioning)

suds1485

right before i bought it from her for a great price(2000) she brought it to honda fr their stupid 29 point inspection. they said she needed xyz so i did xyz also it was based by mileage according to them. when i opened it all up noting showed any visual wear but was already past the point of no return. as far as o2 sensor a friend of mine who is a mechanic said if its starting to go it may not throw a code yet. he was like if the range for it work is between here and there and its almost at either end of spectrum say it might not be up to par but still within specfor the computer not to throw a code. i have access to a scanner so im gonna plug it in tomorrow just to see. if i cant get anywhere ill do the valve leash lol lash its not hard to do. it would be so much esier to have neve learned how to work on cars let alone hondas damn prelude that was the begining of the end as far as working and tinkering with hondas

lazlong

I friend said the same thing. O2 sensors don't read right until they heat up. Yours doesn't run right until it heats up. The #1 O2 sensor is a heated sensor. Ya see where I'm going with this?

It's on the down pipe, below the headers,um excuse me, exhaust manifold. You can see it poking out from behind the heat shield:

suds1485

lazlong im not following you i know where the o2 sensor is. i understand they dont work properly until hot but as soon as the engine starts it putting exhaust out which is hot so the o2 sensor doesnt take long to heat up. im sorry if i sound retarded im pretty tired now.

lazlong

OK, forget everything I've said. After poring over the service manual I was reminded of Adaptive Fuel Trim (AFT for sake of argument). Anything with O2 sensors (HO2S) has AFT. Basically there's this thing called stoichiometric ratio which is the optimum emissions ratio. The exhaust gases switch back and forth: rich-lean-rich-lean (based on the stoichiometric ratio). The HO2S reads the oxygen content in these gases and sends a signal to the ECM/PCM. The ECM/PCM then adjusts the injectors to either run lean or rich.

When you did all the work to it, it changed the stoichiometric ratio. Your old stoichiometric ratio is still in the ECM/PCM memory. Reset the ECM/PCM:

1. Start the car and warm it to operating temp without load
2. Turn ign to OFF
3. Remove under-hood fuse #6 (ECM) for 10 seconds then re-insert
4. Start the car and let idle without load for 10 minutes
5. Turn ign OFF
6. Turn car on and go for a drive

Your idle should now be set but, it may take awhile before the ECM/PCM gathers enough fuel trim memory and resets readiness codes for you to start seeing better fuel mileage. If this doesn't set your idle find someone with a 2-way diagnostic tool and have them reset the ECM/PCM with the tool, then pull the ECM fuse (#6) for 10 seconds, then do the idle re-learn. If that doesn't work you can take it to Honda and have them put the latest update in the ECM/PCM.And if that doesn't do it then you might have an O2 sensor going bad.

Wow, it's 3:30am. No wonder I'm tired. Hope this helps.

Sook_ON

I've got the same problem. Changed the TB / WP, plugs and coils and same thing. Idle's rough as a dog. Took off top cover and verified timing marks (incase skipped a tooth... rare but could happen) and it's all good. At a loss right now. It drives fine - power still there, just at idle it's so rough almost feels like a misfire. Checked the coils and plugs to verify they were firing, and still same problem. Any ideas here? Only 142,000 KM on it... not sure how many miles that is.

suds1485

sook its like 88000
so on sat i cleaned my throttle body and iac also changed the air ilte and spark plugs, and it still doing it. i really dont get it.