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Discussion Starter #1
What's up guys, I haven't been around in a while, but i'm back now...
i've got a nasty problem, and it's got me stumped
I've been having a haunting problem for a little while now with my 87 turbo, and it's got me completely perplexed as to what the possible issue could be. Here goes.
When I am driving with anything less than 1 psi, the car runs fine. I can drive at any level in the RPM range with no problems whatsoever. When I get on the throttle, and the boost climbs to anything over 2-3 psi, the car will bog down like crazy and sound like it burning tons of extra fuel. It's a kind of throaty grumbling, and it will slow down a good amount. It will happen in any gear, and at no certain point in the RPM range. It will throw me forward slightly, and accelerate no more when it happens. If i let off the throttle, it stops, and the car runs fine again.
I checked the turbo a few days ago, and there is absolutely no negative play whatsoever. I spins very smoothly, and doesn't hesitate.
I also checked everything out, and as far as i can tell, there are no boost leaks, so the problem is even more frustrating.
I'm unsure as to what could cause it, my only guesses are something bad in the fuel system, a bad O2 sensor, or maybe the wastegate actuator has failed, and the flapper is just swinging freely, causing erratic boost.
I know a few things about Z's, and I have a decent amount of car knowledge, but this one has me stumped. Any suggestions?
 

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Z31 know-it-all
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1,023 Posts
Pull and tug on the major intake parts. You may not be able to see or hear leaks when the system isn't under pressure.
 

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Discussion Starter #3
finally got it fixed, and it was the most trivial and unexpected problem that i ever could have expected. I replaced my fuel filter today, and when i got the old one out, it was very very dirty and slopped up with... rusty fuel. Turns out i have a rusted gas tank, and the rust built up in the filter, clogging it so badly that when the car needed more fuel pressure to cope with the boost, it just stopped itself up and no fuel made it through.
It runs perfectly now, and i can boost to a full 10 psi without any problems whatsoever. I also replaced my spark plugs at the same time, and they where a very nasty color due to running extremely lean for the past 6 months....
god i'm an idiot.
 
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