Hi lads,

So I've been having idle problems ever since I got my EVO 4 (about a week ago) and I have been searching through many forums to find a solution. Let me first describe the problem:

At cold start the engine goes up to 1200 RPM, which is normal for as far as I know and I've read, but when it's hot it just stays there and occasionally drops to about 1000 RPM and then goes back up to 1200 again instead of going to the target RPM of 850, also it vibrates quite a bit. When it's really hot, it's been pushed a bit and all accessories are on, it ranges from 1300 to 1800 rpm, it's constantly changing. Also there's a bit of a gasoline smell.

I ran EVOscan to check the BISS and the target RPM, target was at 850 when hot so that is good. But it kept running at 1200 RPM and never went down to 850. But when I shut down the ISC it drops and stays at 850; no problems, no (hefty) vibrations, couldn't check the smell as I already was high since it had been idling for a while. As soon as I turn the actuator on again it goes back up to 1200.. This is the main thing I don't understand.

Also I checked if it was either running rich or lean but according to EVOscan AFR is at 14.7 so that is alright.

Last but not least I checked TPS, it is at 14.8 when untouched and at 99.6 when fully depressed (yes, my gaspedal has some issue's, luckily it's taking it's medicine). So that seems fine as well.

So anyone any other solutions/tests I could try?

 

If your smelling fuel, the injector seals may have failed

You can look for wetness or spray that area w/carburetor cleaner while the engine is running & listen for a very distinctive change in RPM