Evo IX bad idle PLEASE HELP
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Evolving Member
Joined: Dec 2016
Posts: 101
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From: Ny
Evo IX bad idle PLEASE HELP
A reoccuring problem with my car has been the idle issues. It first happened last june, replaced IAC and the car ran fine. About a week ago it came back. The car will not drop below 2k rpms. It will bounce between 2-3k. I replaced my IAC again last week and it calmed down for about a day then came back. My tuner (Raif from RRT) said its most likely a dticky TB. I cleaned the TB thoroughly and for about 20 minutes the car felt amazing and then the issue came back. Im going to him this weekend to have him look at it but would like to know a solution faster so he can still check the tune on it when i get there.
Thread Starter
Evolving Member
Joined: Dec 2016
Posts: 101
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From: Ny
First, I would determine one thing.
Is your PCM sending a signal to the IAC to open alot? When this happens your idle should go high.
If the answer to this is NO, then something else is causing the high idle- like an unmetererd air intake (vacuum leak)
Typically, when you make a change to the idle system (like cleaning the TB) you should reset the learned idle "trims" by pulling the battery for a bit.
There is an excellent video on youtube by scannerdanner that teaches you about idle controls
Is your PCM sending a signal to the IAC to open alot? When this happens your idle should go high.
If the answer to this is NO, then something else is causing the high idle- like an unmetererd air intake (vacuum leak)
Typically, when you make a change to the idle system (like cleaning the TB) you should reset the learned idle "trims" by pulling the battery for a bit.
There is an excellent video on youtube by scannerdanner that teaches you about idle controls
Thread Starter
Evolving Member
Joined: Dec 2016
Posts: 101
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From: Ny
Quick update. Cleaned the tb with it on the car since im waiting on the gasket from STM to arrive and i took it out for a drive. I was fine for aboit 40 mins and then i hit a bump and the car stuck at 2k for about 10 seconds before dropping back to normal. Drove for about another 5 minutes and got on the highway and hit a bump, the same thing happened again before i could pull over and pop the hood to see if the throttle was sticking it dropped again. Is it possible bumps are making my cable/tb get snagged? I would like to know before i order another cable from STM ($45 isnt bad and id rather replace than repair) and i also have an evo 8 tb from my brothers evo 8 shell, would that work with my car?
any input on my situation would be greatly appreciated as the weather gets warmer i would like to enjoy my car again
any input on my situation would be greatly appreciated as the weather gets warmer i would like to enjoy my car again
Quick update. Cleaned the tb with it on the car since im waiting on the gasket from STM to arrive and i took it out for a drive. I was fine for aboit 40 mins and then i hit a bump and the car stuck at 2k for about 10 seconds before dropping back to normal. Drove for about another 5 minutes and got on the highway and hit a bump, the same thing happened again before i could pull over and pop the hood to see if the throttle was sticking it dropped again. Is it possible bumps are making my cable/tb get snagged? I would like to know before i order another cable from STM ($45 isnt bad and id rather replace than repair) and i also have an evo 8 tb from my brothers evo 8 shell, would that work with my car?
any input on my situation would be greatly appreciated as the weather gets warmer i would like to enjoy my car again
any input on my situation would be greatly appreciated as the weather gets warmer i would like to enjoy my car again
Thread Starter
Evolving Member
Joined: Dec 2016
Posts: 101
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From: Ny
If you have a genuine problem with the throttle angle sticking open, why not monitor the data pid for throttle position. When you experience this problem, you can confirm if that is the cause by comparing the throttle percentage during the problem, compared to the throttle percentage during "normal" idle.
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Thread Starter
Evolving Member
Joined: Dec 2016
Posts: 101
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From: Ny
If you have a genuine problem with the throttle angle sticking open, why not monitor the data pid for throttle position. When you experience this problem, you can confirm if that is the cause by comparing the throttle percentage during the problem, compared to the throttle percentage during "normal" idle.
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Evolving Member
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From: Ny
EvoM Community Team Leader
Joined: Aug 2005
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From: West Coast
boost leak test finds vacuum leaks too. Classically the throttle body shaft seals will probably be leaky. You can spray things with soapy water and watch for bubbles. What Jp7 was trying to say is you could log the car and see if the throttle is actually sticking open or if its something else. You will be able to see if its sticking by the TPS reading.
I had a problem with my throttle sticking, turned out to be the spring on the pedal itself needed cleaning/greasing. I replaced the throttle cable basically for nothing thinking that was the cause.
I had a problem with my throttle sticking, turned out to be the spring on the pedal itself needed cleaning/greasing. I replaced the throttle cable basically for nothing thinking that was the cause.
Last edited by Biggiesacks; Feb 26, 2018 at 09:19 PM.