https://www.evolutionm.net/forums/sh...d.php?t=152034

There is a link that will tell you the proper way to do a compression test on your car. I did a compression test on my EVO 8 the other day and had a even 150 accross the board.

 

Cool, thanks for the link

 

I would say 150's would be considered low end of good with mid 170's being a sign of a very healthy engine. If you see a difference of more than 15% anywhere across the board it should raise some concern. I would think that if you had a leaking or bad injector that you would see more of a lean condition.

 

OK I just checked the compression and I got 160-170 on all cylinders.

Also the plug smells like fuel bad. Could the injector just be giving it to much fuel at idle, and make it foul out?

I know the car was tuned by Mark at turbotrixx, maybe I should give him a call.

 

Leaking injector is you problem.
.

 

Never heard that one

Try running some injetor cleaner through it

 

Leaking injector makes perfect sense.

If it was a coolant leak. Plug would look real clean as if someone polished it.
It could be oil but I don't think so because he's smelling gas.
Can't be a coil because it would be on 2 cyl. not just one.
Can't be rings or valves since comp. checks out good. But still possible but highly unlikely in this case.

He only feels the stumble at idle not at wot because the duration of the injector is shorter. But if the injector is leaking/staying open when it's not, dumping fuel in the cyl. causing the plug to foul over time.
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When I start the car and drive off it stumbles and misses for about 30seconds, this is just taking it easy like 3-5 psi boost until it warms up, or no boost at all. After that, it runs fine no problem.

Do you think it could be the one plug wire on the coil pack, with the spring in it?

 

^^ You can try switching the 2 coil packs and see if the fouling plug will move to #4.
But usually a bad coil pack would be a more noticeable miss regardless which rpm and more pronounce with more load. You seem to be fine at WOT.
.

 

Nad1370..

If it is the injector, do you think it would through a cel though? Or could have something happened with the tuning?

Also like you said it is fine at WOT, and any throttle position after slight warm up.

Thanks for your help

 

A slightly leaking injector at start-up won't usually trigger the CEL. If it did, it would be a P0172 system too rich. The ecu can still compensate the fuel trims since it's only a short time and in open loop.

Tuning had nothing to do with the injector leaking. It happens but not often.
I don't think it will throw the tune off since it's done at WOT.
.

 

If the plug is wet with fuel when you pull it out, what else can it be besides leaking injector? Especially if the other three are dry.

Try tasting it, does it taste like gas? Just kidding! Tell them turbo trix people to swap your injector out, I'm sure they got plenty of them lkaying around

Only way to test the injector by applying about 5 psi to the diaghram of FP regulator with a fuel pressure guage installed to see if it holds fuel pressure, not so easy without the tools and equip

 

Do any of the evo shops have stock injectors? All I have found was aftermarket ones.

 

Wow, so by leaking injector you guys are really talking about an injector being stuck open? I guess I've always called it by the wrong name. If the injector is stuck open then this could very likely be the culprit although I really haven't heard of stock injectors failing on our cars. This being said, just because I haven't heard of it doesn't mean that it hasn't happened. Most evo shops have a fair amount of stock injectors laying around left over from people now running upgraded ones, give a Turbotrix, Buschur, and/or AMS a call explaining your situation as I'm sure they'll help you out for a fair price. Keep us posted man and the best of luck to ya!

 

How do the dyno numbers sound? Should they be alittle higher, or does this sound right?
This was done at Turbotrix.

This was all done before I bought the car...

WHP=308.26
Torque=302.79