Car is Breaking up around 4k rpm

M

Midnightracinsr

Member
ok guys im going to try to be as specific as possible any help is greatly appreciated I want to solve this but im out of ideas.

here is the problem:
s13 redtop sr20det. at 7psi with stock smic and piping. it can hold boost fine and the vac at idle is around 21

The car basically falls on its face and breaks up around 4k rpm at wot when in boost. It doesnt do it in vac. I did the swap around 2-3 months ago. The symptoms only occured when the stock boost was increased to 9psi.

The list of things that I have tried:

Compression test. all cylinders are at about 140

new Coolant temp sensor

hooked up the modis diagnostic scanner and checked the ecu for codes. code 55 system ok. was the only one. I checked the mas voltage.. good. the tps.was good. the o2 was good so i didnt change that. drove the car with the modis and the maf, o2, coolant temp, tps and everything was in working order.

Looked for boost leaks only found a bad bypass valve so i changed that. but i am ordering a full greedy kit because i think that is my problem.

changed the plugs several times with several diff gaps.

looked at the coil packs the spark to me seems weak because they are not bright white. they are kind of orange.

I changed the fuel filter to a z32 tt filter and I am runing a walbro.

Changed the bypass valve to one from an 04 evo.


Things I think it could be.....

Right now I dont know. but someone told me maybe the fuel pressure is too high

also that there is a leak in the piping or vac hoses.


I have tried anything and i really want my car to be running good again. thanks for all the help.
 
Usually these kinds of symptoms point to an ignition or fuel problem. Are you running rich? If not, make sure all your grounds are good and swap coilpacks with a friend. I'll ignore plugs since you said you changed them and hopefully you don't have a grand canyon gap. There's always the MAF too.
 
what do the the spark plugs say, too ritch, too lean? probly too rich with the walbro, def check the fuel pressure. I installed one and the preassure was to high had to turn it back. good luck
 
I was working on a totally stock SW20 turbo a couple months ago, did the same exact thing, found out the intake rubber piping had a crack in it, and was leaking, the car boosted fine and everything, but since the air that was measured was leaving the intake pipe it was running rich, fouling out the plugs.

You said it happened after you bumped the boost to 9psi, which adds more stress to the rubber hoses, that extra 2psi could have been just enough to burst s small hole in the piping?

also when you took the plugs out after the problem started how did the plugs look like?
the Ignition should be like a bright white/blueish color, orange is not right! check everything on that also.
 
Yeah i burnt out the plugs and it is running def rich. the plugs were really black . I took it to a shop today and they sed that it was an ignition related problem. Im trying to source some coilpacks to try out but cant find any. i ordered the front mount int but its not here yet. thanks for the help.
 
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