vadimkaz29

I love my acura even though it is giving me problems to the point of frustration. I love it and want to fix it ASAP.
I have 1996 Acura TL 2.5 and I recently replaced the engine+transmission with engine and transmission from 1998 TL 2.5. There are many problems to be addressed, but the main has to do with idling and RPM's.
When the engine is cold and I start the car, RPM's go straight to 2300 and it stays there for about 30-40 seconds after which they constantly jumping up and down but only up to 1500 RPM the only way to stop this is to disconnect the sensor from air control valve. As soon as I disconnect it, RPM's go back to normal and it starts normally when it is cold. Also, my A/C is not working properly at idle because RPM's fall to 450 and compressor does not have enough strength to work. It is only clicking and RPM's go up and down. Basically it is only working when I am driving and when I stop at the stop light, it starts clicking as if it is trying to do something and RPM's go up and down rapidly until I turn A/C button off or I start moving again.
I don't think that the air control valve is bad because I installed the one from my previous engine and it was working fine before (unless something happened to it when I took it off) and now I replaced it with another one just in case, and it is doing the same thing. I bought brand new Fast Idle Valve that is right next to Air Control Valve and it did not help.
If you know anything about RPM's and idling on this acura, any suggestions will be highly appreciated... I'm very discouraged because I spent a lot of money and problem remains the same.
I have 18 months daughter and my wife is pregnant with another daughter and she is ready to deliver anytime now. This is our only vehicle and we live in California - it is hot outhere.

TexasHonda

Idle speed is controlled by the idle air control valve, however if there is a large air leak elsewhere ECU may hunt trying to stablize idle and cause an oscillating idle. This means an air leak probably in intake manifold somewhere. Try searching for air leak w/ throttle body cleaner. Engine speed will change when cleaner is sucked into engine at leak.

Also a faulty PCV valve (stuck open) can cause same problem. Check PCV hose carefully for leaks.

AC will work OK, once idle air control system is corrected. ECU maintains idle speed by increasing air flow just before compressor engages.

The Acura manual has a series of possible faults for fluctuating idle speed; idle speed adjustment, IACV, FITV, throttle cable, and Mass Air Flow (MAF) sensor. If you can download the 95-98 TL manual in the sticky post. It has the diagnostics to check all these components.

good luck

vadimkaz29

Can I use brake cleaner instead of throttle body cleaner to search for leak?
By the way, can it be that one of vacume hoses are mixed up? and in case if it is an air leak and I find it, will it fix the first problem that rpm go very high when it's cold?

I appreciate for the suggestion, I did not think of that possible source of my problem.
Thank you, Thank you, Thank you...

TexasHonda

You need a hydrocarbon that will burn. I don't know if brake cleaner is a substitute. You can try.

Switched vacuum lines might cause a problem, but doubtful. Easy to check w/ vacuum diagram under hood.

Yes, once you fix the air leak, if that is problem, it should fix high idle when cold.

Note, long list of other possibilities in shop manual.

good luck