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Car won't accelerate past 3 grand please help!

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Oreostylez

Probationary Member
13
2
Apr 8, 2017
Douglassville, Pennsylvania
I'm new to dsm and turbo cars in general. I'm a mechanic fora living but can't figure out my cars problem at all. When I bought it the guy told me it had a code for the MAF sensor and it wouldn't drive under 4 grand. But once it started moving it ran great. Once I put the new sensor in and cleared the code it would only accelerate to 3 grand then start bucking. But when I unplug the sensor it's back to how it started. I've checked for vacuum leaks and boost leaks. I've checked the computer sensor ground but don't see any burnt paths. Can anyone please help me figure this out?
 
I wonder if being OEM or Parts Store makes a huge difference on MAF's? Where was the replacement from? I have had one go bad and the car ran better unplugged than plugged in.
 
I got the sensor from Autoparts warehouse. And warming up didn't make any difference. I have let it get to operating temp numerous times while trying to diagnose and test drive it. As for fuel pressure, it was revving up fine in neutral for a while and only acting up under load. Now it's started spitting and sputtering at about 4500 so that's something I'm going to have to check when I get a chance.
 
What plugs are you running. I had a friend ounce that had similar issues, after we put in some bpr7 plugs and gapped it the car ran great. Just giving you some possibilities.
 
I would have to pull them again. The carseems to be running really rich judging by the black smoke it blows and the build up on the bumper. I pulled the plugs and cleaned and re-gapped them and that didn't make a difference.
 
You need to see what the MAF is telling you. If it is reading excessive air, it could be running the car rich and causing fuel cut (bucking) at higher RPMS.

It never hurts to do a boost leak test.
 
He said he already did a boost leak test. But I would do another to rule out boost leaks for sure. I know you said you checked the plugs, but I would get NGK plugs since they are what many of us run. Im not so certain that the maf is the issue at this point. He can get another maf and see if anything changes but its getting mad readings from somewhere. First thing is do a boost leak test. You can do the test and find your injector seals and throttle body gaskets are leaking. Definitely keep that in mind.
 
Put a sock in it!!! :D
 
Ok. Well I checked my computer. Twice. I saw a bunch of people that had fixed a blown sensor ground but that was on a different computer then I have.
 
Even if you sneek up on the 3000 mark, it still wont rev past 3? Just trying to see if a fuel flow/volume is having any effect. You say it seems rich but its shutting down on you. You can test fuel flow by unhooking the fuel rail fitting on the passenger side and put it in a can to catch fuel, then if you activate the pump with the pigtail under the hood you can see if it is flow related. Apply 12v to it and the pump will turn on. I am wondering if the pump is going out or the filter plugged is the only reason for this test.
PLEASE DO NOT BURN DOWN YOUR CAR, SO BE VERY CAREFUL IF YOU TEST THIS WAY.
 
I plan on putting on a new fuel filter on soon and I need to rent a fuel pressure tester I guess. What's normal for a 2g?
 
Is it possible that my computer was flashed? How would I be able to find out? And can it be set back to stock? If so how?
 
Just an update. After weeks of trying to figure out my cars problem my friend and I finally figured it out. The reason my car was running like it was did turn out to be a huge boost leak. One of the rubber connecting hoses for the intercooler had a huge hole in it. No-one saw it because it was hidden under the braided cover that was on it. Thank you so much for all the input and help from everyone.
 
Just an update. After weeks of trying to figure out my cars problem my friend and I finally figured it out. The reason my car was running like it was did turn out to be a huge boost leak. One of the rubber connecting hoses for the intercooler had a huge hole in it. No-one saw it because it was hidden under the braided cover that was on it. Thank you so much for all the input and help from everyone.

First post.
"I checked for boost leaks"?
 
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