924Board.org

Guest · Posted: Wed Jun 13, 2001 3:38 pm Post subject:

From: Rick MacLaren
Email: rick-maclaren@home.com
Date: 13 Jun 2001
Time: 15:38:52

Ok...here's a problem for tech guys.

The turbo when it's cold doesn't seem to kick in right...it goes to like 0 on the boost gauge. It has also sputtered when the engine is warm. What's up with that?

Is it possible that there isn't enough oil around the turbo to make it work right? Any ideas?

Guest · Posted: Fri Jun 15, 2001 4:46 pm Post subject:

From: Ian
Email: themechanic@talk21.com
Date: 15 Jun 2001
Time: 16:46:11

I've thought about it and the only thing I can think of is a bent turbo shaft. When is gets hot and expands it spins freely.

Guest · Posted: Fri Jun 15, 2001 7:48 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 15 Jun 2001
Time: 19:48:14

r u sure its the turbo and not just a fuel problem?

Does the car accelerate but accelerate slow as if you didn't have a turbo on it (smooth) or does it jutter and shudder and hesitate like a fuel problem?

Guest · Posted: Mon Jun 18, 2001 8:40 pm Post subject:

From: Rick MacLaren
Email: rick-maclaren@home.com
Date: 18 Jun 2001
Time: 20:40:02

It judders and hesitates. It does not run like a normal 924...but only intermittently.

Guest · Posted: Mon Jun 18, 2001 11:16 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 18 Jun 2001
Time: 23:16:37

Ok well Rick, maybe your manifold cut off switch is screwy, does this juttering happen everytime you go for a drive...it also could be something like a fuel pump relay.
If there is no fuel, it feels like you have no power in the turbo.
When I was driving my 931, it would jutter when i booted it in second since the pressure switch was flakey, it only did this once in a while, but i knew it was the switch because the car cut out completely on my for a split second when it happened.
If you have a turbo problem the car will nto cut out, it just won't accelerate fast.

If it happens almost all the time you drive, I would ground out the fuel cut off switch wire and see if it goes away, just temporarily ground it out.
I think if your turbo wasn't working you would just get poor acceleration and no real jutters...

Guest · Posted: Tue Jun 19, 2001 5:22 pm Post subject:

From: dave2
Email: david.c.russell@lmco.com
Date: 19 Jun 2001
Time: 17:22:39

Rick, I have mentioned this here before, and it may not be your problem, but maybe it will help. Two summers back, I was having the darned problem with my 931, and I just couldn't find anything wrong. Under hard excelleration, it would tend to cut out and then kind of studder between three and four thousand RPM. But, if I excellerated slowly, it would rev all of the way to redline. When it did cut out, I was getting a light cloud of black sooty smoke out of the exhaust. I went through the whole fuel system, and the ignition system, even replacing many of the components, but could not find anything wrong. I even thought it might be a blocked exhaust, so I dropped it, but once again everything was fine. To make a long story short, one day by accident, I found that the elboe connector on the back of the vacuum pipe was cracked on the bottom side. It didn't show up on vacuum checks, because under vacuum, the crack was held closed by the vacuum. But under high boost, the pressure would blow the crack open, venting much of the air to atmosphere. That caused an over-rich condition, causing the misfire. Easy fix once I found the problem.

Guest · Posted: Wed Jun 20, 2001 8:42 am Post subject:

From: Rick MacLaren
Email: rick-maclaren@home.com
Date: 20 Jun 2001
Time: 08:42:31

Even when grounding the switch the symptoms remain.

Guest · Posted: Wed Jun 20, 2001 2:50 pm Post subject:

From: larso
Email: l_porsche@hotmail.com
Date: 20 Jun 2001
Time: 14:50:12

maybe the wastegate is is stuck open, you said it goes to 0 on the gauge... maybe once the exhaust heats the wastegate up it expands more than the spring and the spring is now free to move, just a silly guess, i do not know/