I remember seeing some posts a while back saying something about lighter flywheels throwing a check engine light, but cant find them any more. Does anyone have more info on this subject? I just installed an ACT clutch and Prostreet flywheel and I've been constantly getting a CEL, I haven't been able to pull the trouble code yet, but the only thing I can think of is the lighter flywheel.

 

i cant see that happening.. go to autozone and pull the code, instead of wondering, or potentionally screwing the car up..

 

Not an Evo expert here, but most cars throw a misfire CEL if the engine slows down too much between combustions. Because, on a 4cyllinder, there is no piston with leverage against the crank when the crank is vertical, the engine slows down slightly between combustions with only its rotating mass to keep it going. Reducing the rotating mass with a lighter flywheel increases how much it will slow down between combustions. A misfire will also cause the engine to slow down considerably. So a lighter flywheel sometimes trips the computer into thinking there was a misfire.

*shrugs*

-Adrian

 

no other mods to the car? hmmm.....I bet its ultimately a po300 random misfire or related code. Due to harmonic vibrations normally amplified by the famous lighter flywheel mod it triggers the crankshaft sensor which is very sensitive and thinks its knock, which in turn throws up more fuel in the chamber and wala....u have a rich misfire. It's happened to me when I put my new clutch and flywheel in. But just go to your local dealer and they should have a cure for that bugger(reflash your ECU). good luck.

 

pull the code and then well know for sure

 

Errm. Crankshafts sensors don't detect knock.

 

you can tell that one to the service manager at mitsu because word for word those are his words im writing down. well.....almost all. but it does have something to do with the crankshaft sensor buggin' and then trippin the knock sensor bla bla bla

 

but we wont know for sure unless this guy checks the code he's throwin'

 

Yeah, I'm headed to get the CEL code pulled right after work. Will post up findings soon.

 

It can happen. The lighter flywheel will let the engine rev faster than the ECU expects. So when it see's the (correct) signal from the crankshaft sensor before it expects, it throws the misfire code.

The dealer p0300 fix can aliviate some of this problem, but at some point you will exceed the programmed specs for the ECU.

It happens to me on occasion

 

I haven't heard of this before on the EVO and I do remember a post a few months back referring to this, but the author was referring to a friend with a WRX. It is well known in the Subaru community that the CEL (misfire code) will trip with a light flywheel. We have two weights for the Subaru flywheels (10 and 14 lbs approximately). The lighter flywheel will usually trip the CEL and the heavier one usually won't. Needless to say we sell a lot more of the heavier version for the Subaru. I would think if this was a problem on the EVO it would be widely known, but who knows?

 

Ok, the trouble code was a P0401 (EGR insufficient flow). I checked all the vacuum lines and found two lines with nipples broken off in them I guess when the people who worked on my clutch installed the new one, they must've accidentaly broken something off. The two lines have blue dashed lines on them and I have no clue where they go. Now that the problem is isolated now I just have to get it fixed.

 

good troubleshooting, but also make sure you get that ECU reflashed by the dealer because sooner or later that p0300 nasty code will come up. Its bound to happen. Just a preventative maintenance idea u should not pass up. again, good work.

 

Off topic but how do you like the Prostreet/ACT combo, thinking of getting this myself