The car is a 1994 Accord EX with 155K miles.

I recently had an issue posted about in this thread (https://honda-tech.com/zerothread?id=1757867) that basically fixed itself and went away on its own.

Not even 2 weeks later, she brought back the car with a new symptom. While in park/idle, the idle bounces around between 100 and 1000 RPM, and the car feels like it's about to die every time it dips down to the 100 range. This happens when the car is parked, or while I am coasting, and is not noticeable when I am on the gas (although it does feel a bit jerky).

I've done some searches on this, but can't find anything substantial to follow up on. Can any of you please give me some ideas/pointers of what to look at to find the origin of this issue, and any things I could try to troubleshoot without throwing parts at an unknown problem?

TIA

 

up...

 

remove and clean idle control valve after you check for vaccum leaks....

 

How do I check for vacuum leaks? Just listen for a whistling sound, or is there a more accurate way of pinpointing it?

 

Ok, I hate to bring this thread up from the dead, but there are new developments. Since I posted this, I have not seen any more erratic idle. However, the car has started dying very suddenly, while in "Drive" but not actually driving (foot on the brake). After it does, it starts again without a problem, and I am able to drive it, sit at lights, etc., until it dies again.

HELP PLEASE!!!

 

oxygen sensor? ignition coil? have someone check parameters of oxygen sensor spec with pgm tester. should have listed in shop manual. sounds like starving for fuel/air mixture

 

I am not getting a CEL for any of these. Other than measuring, is there any other way to check? Could it be the IACV or the FTIV?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dynamo &raquo;</TD></TR><TR><TD CLASS="quote">I am not getting a CEL for any of these. Other than measuring, is there any other way to check? Could it be the IACV or the FTIV?</TD></TR></TABLE>The FITV should close itself up when the engine's warm. So I think the FITV can only increase the idle, not drop it.

IACV is supposed to open to maintain idle. If it's sticking, or going bad, it can do exactly that. Clean it out with TB cleaner. While you're at it, clean out the TB itself, especially around the bore where the throttle butterfly closes.

Then check your base idle rpm & go from there...

 

These are the main things you could check, in review:

1. Vacuum leak or air leak. Spray starting fluid around by the intake manifold on a cold engine. When the engine speeds up, that is where the leak is. It could be a bad gasket or a badly fitting hose.

2. The idle air control valve. Clean or replace. Use good gasket!

3. The throttle position sensor!!! PLay with it (gas pedal) and if the idle acts funny, erratic, that is the problem. (It was in my case.)

4. MAP sensor. Plug and unplug its vacuum hose and see what happens.

5. Idle speed screw -- set it -- can make quite a difference.

6. Reset computer after each change -- brown 7.5 amp fuse in the underhood fuse box. This must be done!

Buying a Haynes manual (eBay?) is a good idea. Good luck!

 

Yo, i'm having the same trouble. The only difference is that mine won't die. It will just idle really crappy. I do get an engine miss while cruising, which makes me think that it isn't the iacv.

Dynamo, what's the latest on your idle problem?

 

also. for the vacuum leak to test for. Is it ok to kinda freely spray the throttle body or carb cleaner? I know it's not good on electronics so how careful should I be in spraying it.
Sorry to hijack the threat but hopefully it isnt to much of a distraction and i didnt want to create a new thread.

 

the ultimate tool for vacuum leaks is a smoke machine. PERIOD!

You may want to call around town to mechanic shops and ask to see if they might have one. There would have to be at least one of them with a smoke machine.

 

UPDATE - I took off and cleaned the IACV, and it fixed the problem - the car idles perfectly stable at 500 rpm at idle and hasn't died since. Thanks everyone for your responses!

 

lol my mechanic told me that it was normal on accords for this time of season and that i should just let the jumping idle die after 5 mins.

 

I don't think it's normal - never had a car that did anything like that "by design".

 

lol, yeah that's not normal.
It may happen to a lot of accords with age but it's not supposed to happen.
It's normal if your a lazy *** and don't want to fix your car, it won't be fatal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gulfview &raquo;</TD></TR><TR><TD CLASS="quote">These are the main things you could check, in review:

1. Vacuum leak or air leak. Spray starting fluid around by the intake manifold on a cold engine. When the engine speeds up, that is where the leak is. It could be a bad gasket or a badly fitting hose.

2. The idle air control valve. Clean or replace. Use good gasket!

3. The throttle position sensor!!! PLay with it (gas pedal) and if the idle acts funny, erratic, that is the problem. (It was in my case.)

4. MAP sensor. Plug and unplug its vacuum hose and see what happens.

5. Idle speed screw -- set it -- can make quite a difference.

6. Reset computer after each change -- brown 7.5 amp fuse in the underhood fuse box. This must be done!

Buying a Haynes manual (eBay?) is a good idea. Good luck!

</TD></TR></TABLE>

I vote for number 5 if you are only seeing this at idle. Has there been any major work done to the car recently?

 

uh, there are a lot of things that control the idle, and only manifest problems during idle

 

Hi,

I'm having the same problem on my 1994 Accord LX automatic (non vtec) idle bounces up and down between 1000-1700 RPMS, when engine is warm, cold, whatever...

i cleaned the TB, IACV, FITV, and checked for vaccuum leaks, cleaned the EGR valve, but nothing, still bouncing idle. Oh yeah, this only happens in park and neutral.

I checked out the MAP sensor per the Haynes manual and suspect it is out of whack... could this cause the bouncing idle problem?

Thanks!

 

i say vacume leak.
look under ur hood and see any hoses not attached to anything.

 

I thought the same thing, but i already checked for leaks with a propane torch, nothing.

I triple checked all my vaccuum lines and electrical connectors and everything is connected properly.

Also the problem only happens in park and neutral, but goes away in drive and reverse.

I've done a lot of searching and a lot of honda owners seem to have this problem... anyone here successfully fix it, and if so how did you do it?

Any ideas?

Thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beaterhonda &raquo;</TD></TR><TR><TD CLASS="quote">Also the problem only happens in park and neutral, but goes away in drive and reverse.</TD></TR></TABLE>Set your base idle speed. I'm guessing it's set too high. Then your IACV tries to go closed beyond it's range when there's no load. But it's OK when there's a little load, like the drag of the tranny in gear.

Warm it up completely, turn off all electrical loads, & jumper the SCS connector. Then unplug the IACV which will cause the idle to drop low. Use the idle screw to set the base idle rpm. You'll have to look up what rpm that's supposed to be, but it's always considerably lower then the proper idle speed. For example my '95 GSR base idle was about 500 rpm.

When you plug the IACV back in, the idle goes back up where it belongs. Then reset your ECU. Start the engine without touching the gas pedal AT ALL. Let it idle for about 10 minutes without touching anything.

 

Jim,

Thanks so much for your reply!!! Just a quick question, what does SCS stand for, and where is this connector located?

Thanks agian i'll give this a try in the morning!

 

Newbe here and i have an idle problem with my 97itr in my hatch. So what exactly is the SCS? i dont know either.

 

SCS connector is that blue plastic plug which you jumper to read ECU error codes (check-engine light flash codes). You also jumper that thing when setting spark timing & setting base idle speed.