Greetings,

First let me state that I have searched the forum and could not found any thing could help me with my problem.

I have an 88 Prelude Si 145K. It has been running very well until very recently. When the engine is cold, there is absolutely no problem/symptom. However, after driving around for 5-10 minutes (warm engine), I experience a problem that the car can not maintain idle speed at all. The engine just dies. The only way for me to keep it running is to keep my foot on the gas pedal. The problem is very repeatable. You thoughts and suggestions are gratefully appreciated.

Cheers
tp

 

can you turn up the idle?

Does it only die when the RPM's drop from like 3,000 when you rev it, or can it not even maintain a constant idle without help?

 

see if your fuel system is holding pressure. I had a fuel pressure regulator that went out and would give enough volume of fuel to keep the motor running while decellerating.

Best way to do it is drive the car...stop and turn off the car...wait like 1 min and take off your fuel cap...if you hear any of the pressure bleading off its fine if not the your fuel pressure regulators diaphram is bad and not keeping the system pressurized enough.

Also have you noticed it take a little bit longer ora couple extra cranks to start the motor?

This is just a theory, it could be somthing totally different but that fixed my problem.

 

sounds like your idle air control valve (IAC.) if it is like newer hondas there is a fast idle valve and an IAC. when the car is cold the fast idle thermo valve maintains idle speed, but once the coolant reaches 86 degrees the IAC controls the idle, and if it is clogged or broken the car will die. at the moment i dont have access to AllData to get the specs on your car, but if you know or can find out where the IAC is, remove it and clean the filter with carb cleaner. most likely it is dirty, tho it could be broken (assuming this is the problem, which is a huge problem for hondas)

 

Luda94, That sounds very logical. After reading all other idling problems in this forum, I kinda made the same conclusion. Your diagnosis confirms my thought. However, the only thing that still bothers me a little is the role of the ECU. Isn't this device also involing in the maitaining of the idle? If yes, could it be an other suspect as well?

Thank you all other for your helpful thoughts.

 

Hello Greyout and 95 lude, here is a additional info - replying to your posts

1) It just cannot able to maintain idle at all when the engine is warm. I have tried to adjust the idle screw, but it doesn seem to help. The only thing works for me so far is adjusting the throttle cable, but it is annoying because it makes the engine runs too fast when cold.

2) the fuel pressure is within spec.