Date: Mon, 15 Jun 1998 08:22:37 -0700 From: Justin VanAbrahams <jvanabranopsamnet> Subject: Re: 85 900T low boost problem
Scott A. Stratmoen wrote: > > But wait, there is the temperature thing. I just can't see the bearing > surfaces being effected by outside temperature (oil temp shouldn't be an > issue after the engine is warm). Air density is greater at lower > temperature. This tends to point to the exhaust system or the > intercooler. > > Suggestions on what to do next? > It's possible that your problem may be fuel related. If your mixture is lean, it'll be more susceptible to detonation. Colder air temps will help cool the intake charge and reduce detonation, whereas warmer air temps will aggrivate it. It's possible that your low boost pressures is just the APC solenoid doing what it's supposed to be doing - keeping knock at bay. The easiest thing to do will be to bypass the APC system to verify that mechanically the intake system is okay. You can pull off the hose running from the wastegate to the APC solenoid and drive the car around. If boost is right, that means that the turbo, intake, and exhaust are all doing what they should - DON'T leave your car like this or detonation CAN AND WILL grenade your engine - you'll be completely defeating the APC system. If the car runs well, I'd look into your fuel system. Check your fuel filter first, then the fuel pump, followed by the fuel pressure regulator and then the injectors - that's the order from most likely to least likely. The other possibility is that you might have a blown head gasket, although this is fairly unlikely since ambient temperatures would hardly affect engine temps. But, if you had one you'd obviously be able to look for lost fluids and such - don't count on mixed coolant and oil as a sign of a blown head gasket as it won't always happen. -Justin
 |
 |
 |
 |
 |
