944hal

During a recent club race weekend, my car was experiencing a power loss due to low boost (944 Turbo). I've pretty much ruled out any leaking hoses. When starting out in a session I had 12 to 12.5 PSI boost (after market DME chip and stock KLR). The longer I ran, the less boost I had until, in two instances, at low RPM in third gear, I had no boost at all, zero on the aftermarket boost gauge. I did replace the DME and KLR boxes for one session with stock units (so the owner said). The car would not start with the stock boxes. It was excessively rich. I fired it up with the old brain, let it warm up and swapped out the DME and KLR for the loners. Although running extremely rich, the boost stay on most of the whole session, although it was a little erratic at the start. Fuel issue or something else? Any of you guys experienced anything like this, or have any ideas?

Van

Clogged air cleaner or plugged up snorkel?

drive135mph

Do you have a cat? the pattern of power loss as the car warms up is typical of a clogged/melted cat. Maybe a leaking BOV or sticking waste-gate? Have you driven more the 14000 feet above sea level?! (common problem)

944hal

I have a K&N air filter that was cleaned and oiled not too long ago, and the snorkel is free of mice, chipmunks and other critters :-) The cat is long gone, except for the one that resides in my garage, and the car hasn't been out of GA in the last 20 years, except for Summit Point and Daytona, so elevation is not a problem. The BOV tests OK, not sure about the Waste-Gate. It's a Lindsey rebuilt unit that's been on the car for over 10 years. Air Box? My thinking is the computer is opening the waste gate. I had a similar problem years ago due to the stock chip thinking the car was over boosting and going into limp home mode. About a month ago the hose from the cyclic to the waste gate got melted through. Too much slack. As soon as that happened the boost went to 18 PSI, so I know it's capable.

Oddjob

I've had a TPS go bad and the car ran really rich, until it wouldn't start at all. Any back firing?

Any KLR fault/blink codes?

Also, check the bottom of the intake hose out of the turbo to the intercooler feed pipe. Had one of those split on the bottom side, and it stayed partially sealed and the car ran normal until getting into the boost, then there was enough pressure to push the split open and would lose boost pressure.

944hal

Jim B
Great suggestions. Had not thought to check the blink codes. The TPS clicks when it's suppose to but I'll check it out. It only ran real rich with the borrowed CPU. No backfiring, except when I let off the throttle. Getting some fire out the tailpipe, but I assumed that's normal for a Turbo. Hose from the turbo OK. Just had it off yesterday.

Oddjob

That's pretty rich. Are you running more fuel pressure (non-stock FPR)? How do the plugs look?

944hal

Stock pressure regulator. Plugs look black, fouled. The chip I'm using I purchased from EBay just to test a theory about my stock chip. It could be programed for a much different setup. My engine is stock since I'm running SP3. Thinking about getting a Dyno tune and a new chip cut.