poorporscheturbo

Yesterday on the freeway, the engine started stumbling (only during load). I pulled off and noticed that the car idled ~200.

Opened the hood, noticed a vacuum hose had unscrewed itself (off pipe that runs from turbo outlet to intercooler). Found the bolt and re-attached it. Idle fixed.

However, now the car has weak boost and maxs
out ~1.3bar@5000. The boost also doesn't hold. (I was boosting ~1.9 before the stumbling yesterday). I've read the previous posts regarding KLR, wastegate, etc...

Someone mentioned the KLR going into "limp" mode, thereby limiting boost to 1.25bar. I'm hoping that this is what happened? If so, do I need to reset the KLR unit? Or does it reset itself. Will pulling the battery reset it?

If not I guess I need to troubleshoot the wastegate? Any tips or suggestions would be greatly appreciated.

Oh also, my airbag lights are on? I've got the instructions on how to reset it (hopefully a glitch), but what are the common problems with 951 airbags?

Much thanks,
Mr. Poor
1987 951 ~126K

Russ Murphy

Mr. Poor,

I'm assuming the line that unscrewed itself is the one connected via the large banjo bolt. There are(were) two small washers on either side of the "banjo" part. If they are missing or misplaced that boost line probably isn't sealing and you could be bleeding off your boost.

Russ

poorporscheturbo

Thanks Russ,

I found the two washers and put them back on as well. However, the boost remains unchanged... maxing ~1.1 bar. I also pulled the battery overnight (someone told me this may reset the KLR). Didn't help. So I guess I'm stumped. Any other easy checks I can do? I guess I'll try plugging the wastegate line and seeing if I boost up fully?

Thanks,
Poor Porsche

adrial

I'm not too sure, but I would think plugging up the wastegate line would be bad...very bad...if by this you mean the line that the banjo bolt is on...
The wastegate would never open...and you would overboost pretty bad...talking like 25psi+. Not good...

smarter people will probably correct me

poorporscheturbo

Beats me. Someone in another posting said you could plug/pinch it for diagnosis. Definitely not to be used as a solution.

If I gently boost till 3K with it plugged, and I see full boost, then shouldn't it confirm that the wastegate still works?

But yeah, definitely should be done with care. I don't want to destroy anything.

Danno

yeah, that's an easy test. Just clamp shut the line going to the wastegate and gently give it gas to see how much boost you get. Do a couple of runs with more and more throttle. If you get full boost (and more), then wastegate's fine. Problem is in the KLR/cycling-valve combo, which is bleeding off boost prematurely.

Dan87951

Right after I installed my MAF, my car would do something similar to yours. It would boost no higher than the stock 12psi. To solve this I had to restart the car. It sometimes took 2 times until I could start boosting to 15-16psi boost. But it worked!!