Idle Problem. Please Help

[pwpanas]

Originally Posted by panicos

I have replaced the IACV a second hand one from a friend but no luck. Ive also checked the Air intake sensor & coolant and the ok also. Done many ecu resets but still no luck

Have you checked for boost/vacuum leaks? If a boost/vaccum leak exists around the intake plenum area, it can (inappropriately) function as a secondary IACV. If your Supra uses a maf, this additional unmetered air will cause an over-lean condition at idle.

Also note that some boost leaks, especially ones in the intercooler piping, can partially seal up when hot, due to expansion of the couplings, clamps or intercooler pipes.

[panicos]

Originally Posted by pwpanas

Have you checked for boost/vacuum leaks? If a boost/vaccum leak exists around the intake plenum area, it can (inappropriately) function as a secondary IACV. If your Supra uses a maf, this additional unmetered air will cause an over-lean condition at idle.

Also note that some boost leaks, especially ones in the intercooler piping, can partially seal up when hot, due to expansion of the couplings, clamps or intercooler pipes.

This is the only thing I have not checked 100%. It might be a cracked hose. I have to spend a few hours searching for leaks and this what I am planning to do asap. Do you have any idea about the sensors that have effect on the way IACV works?. There is also a vaccum hose connecting the intake plenum with the throttle, do you have any idea what it does ?. Cant find if there is a crack on it. I will get some Samco Vaccum hose and replaced as may as I can. This might help.

[pwpanas]

Originally Posted by panicos

This is the only thing I have not checked 100%. It might be a cracked hose. I have to spend a few hours searching for leaks and this what I am planning to do asap. Do you have any idea about the sensors that have effect on the way IACV works?. There is also a vaccum hose connecting the intake plenum with the throttle, do you have any idea what it does Cant find if there is a crack on it. I will get some Samco Vaccum hose and replaced as may as I can. This might help.

The best way to check for boost leaks is to pressurize your entire charge-air system with an air compressor (up to about 30 or 40psi - if it can handle 40psi cold, then 20psi or so hot should be no problem). With 40psi of air in your charge-air system, you should be able to hear any/all boost leaks loud and clear.

[panicos]

Originally Posted by pwpanas

The best way to check for boost leaks is to pressurize your entire charge-air system with an air compressor (up to about 30 or 40psi - if it can handle 40psi cold, then 20psi or so hot should be no problem). With 40psi of air in your charge-air system, you should be able to hear any/all boost leaks loud and clear.

thanks very much , i can do this . I have an air compressor and im looking forward to tomorrow morning to do my tests. That's clever , never thought of it..Many thanks and i ll keep you informed.