Car wont go past 3k rpms but will rev past that

[evood69]

I just picked up a 2g project car this Thursday and bought it having some problems, but for the most part are fairly easy fixes. As the title says the car will not drive past 3k rpms, if it is in neutral it will free rev all the way to 6500rpms. I drove it home which was about a 20 minute drive. I have changed spark plugs, switched out the MAF (to one that I know is good). Checked for boost leaks and havent been able to find one. Also checked the ECU and it seemed to be in good condition, no leaky caps or smells. The car has a wiring nightmare though. Could that be causing the problem? Or has anyone experienced this before that might be able to lead me in the right direction on what it could possibly be??

 

[pats16valve]

What mods if any is car supposed to have?

 

[spyderdrifter]

I had bad compression in my '95 6 bolt GST last year. Your description sounds like what I went through, except after it happened and I shut the car off, it wouldn't start again. Checked compression and it was in the 70psi range in two cylinders and 40psi range in the other two. It too had a seriously jacked up wiring issue, had to replace the entire engine harness because of it. Just a few ideas for you. Good luck.

 

[serrilion]

I've had a simliar issue with a car before. It turned out to be the Damn Fuel injectors, they would allow enough fuel to 4.2k and then it would be as if I hit Fuel cut in WOT ... I was like wtf

I don't know if its your problem, but also another idea

 

[BurrowZ]

Check your spark plug wires too.

 

[evood69]

Well I didn't check the compression prior to buying it which I maybe should have and I will tomorrow, but for the price I paid luckily I won't get burnt if that is the case. Modifications would be a bigger turbo, but on stock injectors. I turned the boost gauge almost all the way down because the gauge that came with the car wasn't working. t3/t4 megan racing exhaust mani, t3/t4 .50 trim, 3 inch turbo back exhuast, no tuning management of any kind. All the other mods wouldn't affect the engine itself in anyway.

 

[serrilion]

With no Management could be a nightmare of things.... Injectors with no boost deff rule them out, inless they were bad to begin with... Deff do comp and wire check! GL

 

[spyderdrifter]

Only other thing I can think of is your stock injectors not being able to push enough fuel for your turbo. Did you turn down the boost before or after this issue?

 

[boost4me540]

You mentioned the car has a wiring nightmare, could you elaborate on that a bit more? It there are a lot of wiring troubles then I would bet that would have something to do with it. Also as everyone else says do a boost leak test, compression, and a leak down. I see that we live fairly close. Let me know if you need any help, I am new to the site but have owned several DSM's over the past 4 years.

 

[evood69]

Well just a little update for anyone checking back on this. The wiring is BEYOND shot. I tried everything I could then ended up taking it to my mechanic. They said they didn't even know where to start. The computer was somehow bypassed with a lot of the wiring from the previous owner. So needless to say I scrapped the idea of fixing it and will be pulling the engine and tranny. Now time to try to find a 2g gst shell that will match what I have.

 

[montm82]

first step would be to check your fuel, air intake (vacuum leak), and ignition. it could be any three of these. just go through them one at a time and eliminate until you get to the problem. i had a issue like this with my 2g, it turned out to be a bad injector. i found this out by starting the car and unplugged each injector one at a time the one that doesnt effect the ideal when unplugged is bad.