Date: Sat, 13 Feb 1999 00:51:12 -0600 From: Michael Oakes <michaelonopsamnet> Subject: turbo problem '83 900T
I have problems with low boost. When the engine is cold, I can get on it pretty hard, and the turbo will boost pretty well, almost to the top of the yellow. However, once the engine is warm, it won't boost as high. If the engine is warm, and I floor the accel, I get almost no boost. I replaced the solenoid that controls the wastegate, and that seemed to help some. I get more boost now than I did before. The differnece between performance when it's hot or cold is HUGE. I beleive the turbo is quite out of adjustment, because the boost somes on very fast when cold. If I take off the vacuum line from the solenoid to the vacuum unit that opens/closes the wastegate, it boosts until it opens that other valve that causes the car to nose-dive when it opens. The turbo make no unusual sounds that I can hear. I did replace a split vacuum line a few months ago that had rendered the car almost undrivable. I also have low compression in one cylinder. Could that be causeing the problem, maybe setting off the knock detector? I got 155lbs in the other three, and 110lbs in the bad one. The engine was rebuilt about 20k miles ago. If I accelerate constantly, it will boost to a certain level, hold for a few seconds, then the boost will decrease abruptly.