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Ecotec EFI problems......

HotRod82

Well-Known Member
I have a Redline 2.4 ecotec in a play car that has always ran perfectly until the last trip out it started this high idle problem. Car starts fine, runs fine, pulls hard but when you let off the throttle it idles at 2500 to 3000 RPM. Unfortunately, I live in Kansas and I do not have a shop around here that can plug into the MEFI-5 computer to help diagnose the problem. I figure someone in class 10 or superbuggy has experienced this? Any help would be appreciated!
 

Sean At CBM

Active Member
Seeing that you have a MEFI 5, I am assuming you have a cable style throttle body on the Ecotec? If so, I would start with replacing the IAC valve. Use a 05 Cavalier as the make/model if you go to the local parts store
 

WALSHMOTORSPORTS

Well-Known Member
Now tell me this isn't just cool. The guy has a Redline engine and his direct competitor totally helps him out. Nice work CBM.
 

HotRod82

Well-Known Member
Hey thanks for the reply Sean, but it's a fly by wire setup. Unfortunately, I sold this car to a kid in KS and it started acting up on him right after he bought it from me. I've been trying to help him out as he has not been able to find anyone local (in KS) that can help him. It's a 6 pin fly by wire setup if that helps you shed some light on it.
 

Sean At CBM

Active Member
I would start with the basic stuff. Clean the throttle body, make sure no vacuum caps cracked or came off, see what the fuel psi is set to and clean the air filter. If you can, have him do the good'ol vacuum leak check with some brake clean. Spray where ever a seal is and see if the RPMs change.
 

HotRod82

Well-Known Member
We started there with the basics and he is confident he ruled out an air leak. Air leak was my first suspicion because the car was running perfectly, then all of the sudden it wasn't. Obviously something has changed. I don't think he checked the fuel pressure though, I'll have him check that. Thanks again for taking the time, I'll definitely be using CBM more in the future!
 

drofmij

Well-Known Member
Have him check the intake to make sure all the vacuum ports are still plugged in the intake. I was told the intakes are notorious for leaking where it bolts to the head.
 

turbodon

Well-Known Member
Fly by wire TB's have no IAC valve....
Mine does this too... 2.4 Ecotec w/ mefi 5 computer.
When it starts to go into high idle, turn the engine off, and then turn it right back on.

If it's idling normally after a restart its not an air leak.
I'm not really sure what it is, but mine's done it since day 1.
 
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