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+--- Thread: Turbo help needed (1990 300D) (/showthread.php?tid=1998)
Turbo help needed (1990 300D) - amcya - 11-23-2010
Motor runs great and so does the turbo...when it wants to. The boost is intermittent. I will accelerate up to speed, turbo responds quickly, 15-17 lbs boost. I will start to cruise, boost will drop and won't come back up. Maybe the next couple of times I will accelerate I will have only 1-2 lbs or 0. Sometimes i will be in the middle of accelerating and the boost will jump up or drop off. It's like a switch just turns off. Does anyone know where I should start looking? Can I go with a manual controller and ditch these solenoids? Thanks.
RE: Turbo help needed (1990 300D) - willbhere4u - 11-23-2010
First check the turbo shaft for play!
RE: Turbo help needed (1990 300D) - tomnik - 11-24-2010
also check the overload protection valve in the boost line.
Or just bypass it for testing only to be sure.
Tom
RE: Turbo help needed (1990 300D) - E300TSC - 11-24-2010
Yeah, isn't there some sort of boost "switchover" valve in these cars that controls the wastegate?
RE: Turbo help needed (1990 300D) - amcya - 11-24-2010
I clearly think I have narrowed it down to a vacuum or switch issue. I don't think there is a problem with the turbo, wastegate or actuator.
Where is the overload protection valve? I see the three valves by the airbox but they only have vacuum reference.
RE: Turbo help needed (1990 300D) - tomnik - 11-24-2010
follow the line connected to the ALDA.
The valve should be on the driver side somewhere in the engine compartment.
Electrically the valve is connected to a pressure switch which might be in the intake manifold. Over pressure there makes the valve swich on and vent the ALDA (disconnect boost to ALDA).
Tom