When I turn on the engine and it is cold, the engine is almost die and rpm is shaking.
It is very similar diagnosis of idle control valve problem but I change ICV already last year.
When I just park the car with engine on, it is not stable but still on.
However, if I push the accelerator and detach my foot from accelerator, the engine is almost die.

When the engine is hot, it is better than the condition of the cold engine but still not stable.

I think it is the problem related to air something. I don't know what the problem is.

My car is Acura CLS 2002 with 70k miles (pretty low).
Thank you

 

Are you up-to-date on normal maintenance (plugs, air filter, vacuum leaks, ignition coils, pcv valve)?
Are there any OBD2 codes?

Otherwise, it sounds like a fuel delivery problem: anything from dirty injectors to fuel pressure....

 

NO, I didn't do normal maintenance you mention above but I changed spark plug, and idle control valve). There is no OBD2 code. That's why I am almost crazy. I cannot find the real problem. Could you give other recommendation? Thanks a lot !

 

First thing, suspect bad tank of gas? Or if it's been babied too much, or sat too long, it might just need an Italian tune-up. (Half-kidding, but cars in general don't like sitting still too long.)

At your car's age, it should have had the timing belt replaced once by now. When did you do it?
If the car's never had a TB changed since new, then look for a local Honda/Acura specialist, and he'll prob know right away what your problem is.

In the meantime, maybe start running a fuel injector cleaner and keep track of gas mileage.

 

Thanks for your comment. I changed the timing belt one year ago. Maybe the fuel injector is the problem but the symptom is reduced when the engine is hot. In my understanding, if there is a problem in a fuel injector, then the symptom should be same with cold engine.

 

Symptoms: 2002 CL-S w 70k runs and idles poorly when cold, slightly better when hot. No codes or CEL. Are you sure there are no 'pending' codes?
Summary of car's history: New timing belt, new plugs, new IAC valve within about a year. Any other maintenance or issues? Is this right?

It could be that you have fouled injectors, but the same gunk (deposits) that fouls injectors also fouls everything else, from combustion chambers all the way back to the throttle body and IAC valve. You have added a bottle of Techron or similar by now, right?

Was the IAC valve changed for the same symptoms you're having now? Did you replace the IACV yourself? When it was changed, was the throttle body and intake also cleaned? If not, it's likely that the same gunk that clogged the old IACV has now moved around and gotten into the new IAC valve, causing the same problem. Same gunk also gets into intake manifold and clogs EGR system, and if bad enough, eventually trips a code.

 

Simple stuff first: check operation of PCV and check for correct vacuum hose connections and coolant hose connections. See p.11-24 and p.10-3 of Helm's manual.

 

Symptoms: 2002 CL-S w 70k runs and idles poorly when cold, slightly better when hot. No codes or CEL. Are you sure there are no 'pending' codes?

There is no code never. Mechanic and my friend checked it.

Summary of car's history: New timing belt, new plugs, new IAC valve within about a year. Any other maintenance or issues? Is this right?

Yes, New timing belt, new spark plugs, new IAC valve one year ago, new fuel pump relay, new power steering pump, engine cleaning.

It could be that you have fouled injectors, but the same gunk (deposits) that fouls injectors also fouls everything else, from combustion chambers all the way back to the throttle body and IAC valve. You have added a bottle of Techron or similar by now, right?

No, I never add other things like Techron. But I can smell something not good.


Was the IAC valve changed for the same symptoms you're having now? Did you replace the IACV yourself? When it was changed, was the throttle body and intake also cleaned? If not, it's likely that the same gunk that clogged the old IACV has now moved around and gotten into the new IAC valve, causing the same problem. Same gunk also gets into intake manifold and clogs EGR system, and if bad enough, eventually trips a code.

At the time when I changed IAC valve, the symptoms is almost same. The difference is that the symptom at the time is typical symptom of IAC valve like engine off in idling. It was not matter whether the engine is hot or not. However, now the engine is not off when the engine is hot although it is not stable. When I changed IAC valve, I and my friend also clean the throttle body. He told me that it is good.

 

Try to rule out the simple stuff, like bad gas or extreme deposits: Add a bottle of Techron and fill up with a tank of gas from a 'top tier' supplier. Drive more aggressively to 'loosen the cobwebs' (Italian tune-up).
http://www.toptiergas.com/retailers.html

Are the new plugs same as OEM NGK?
Check PCV?
Is there any change in the cold and hot idle when the AC is switched on and off?
Do both fans come on when it's hot?
At cold idle when it's idling poorly, disconnect one ignition coil at a time and note if there's any difference. A bad coil should eventually trip a code and CEL...

 

Try to rule out the simple stuff, like bad gas or extreme deposits: Add a bottle of Techron and fill up with a tank of gas from a 'top tier' supplier. Drive more aggressively to 'loosen the cobwebs' (Italian tune-up).
http://www.toptiergas.com/retailers.html

Are the new plugs same as OEM NGK?

It is OEM.

Check PCV?

I don't know how to check PCV.

Is there any change in the cold and hot idle when the AC is switched on and off?

Yes, when the AC is switched on and off, the car is shaking. It looks like that the car need more air in AC on but the air is not compensated well.

Do both fans come on when it's hot?

Fan is working well.

At cold idle when it's idling poorly, disconnect one ignition coil at a time and note if there's any difference. A bad coil should eventually trip a code and CEL...



Thank you so00oo much for your advice.

 

I have same problem, Only died a couple of times. New plugs New TPS new coil all others working fine. It dies and I restart then it is fine.
Any help appreciated.

99 TL
175000 Miles
New timing belt water pump, whole kit.

No codes or pending Codes.

 

Replace all 6 ignition coils.
Try tapping on the Main Relay next time it acts up. It's up under the dash about in line with the footrest. Look at these links for your symptoms:

Everything there is to know about your Honda/Acura main relay:
How the Main Relay works
When the Main Relay goes bad

 

Thanks Tosh

 

Let us know how it goes!

 

I tapped on the relay no difference, today it did the same thing. Engine cold and it was cold overnight. Died and I restarted it and it ran fine after that. Could it be a bad battery?

 

Could still be the main relay having cracks in the solder joints. (very common)

 

Where would I find the relay online?

 

If the starter is turning at the normal speed then the battery is fine. Sometimes a bad/intermittent ground can cause strange stuff. And you still have no OBD2 codes or pending codes?

Right, it still could be the relay. If you send me the old relay I'll reflow the solder for you no charge. Once you get it out, you'll see the large solder joints that need heating up, and maybe someone you know locally with a soldering iron can reflow it for you.

 

RELAY ASSY., MAIN (MITSUBA) for 2002 Acura CL COUPE|39400-S84-003


but like Tosh says, a reflow is cheap/free and can fix it too

 

Is it only a cold start problem? Because in that case my first suspect would be a gummed-up Idle Air Control Valve. I've had that too (along w bad coils and flaky relay).
Could you give a summary of your symptoms?

 

But in his OP, he said he replaced that IACV already


Did you replace with an OEM one? That could be it too..

 

It was an aftermarket TPS, Acura will not sell a new TPS without the Throttle Body.

 

AHHH

I got confused... lfalsetto isn't the same as OP, OP replaced his IACV, lfalsetto only reaplaced his TPS..


Check your Idle Air Control Valve

 

IACV is separate part, right? Wouldn't hurt to take it off and clean it if it's never been done. At least that would rule it out when that relay acts up again....
Did you see your symptoms in that link? And what are they again?

 

IACV is seperate from TPS, yes.

IACV here:

VALVE SET, ROTARY AIR CONTROL for 2002 Acura CL COUPE|16022-P8A-A03


It's located under the Throttle body.