1999 turbo saab 9-3

groker · June 21st, 2009, 11:14 AM

My saab started stalling (the engine acts as if it stops running, and then starts running again). This causes the rpms to fluctuate (sometimes going down 1500 rpm before coming back up). However, if I let the engine idle, there is no stalling. The longer I drive it, the worse it gets, until it stalls when slight pressure is applied to the accellerator. When I turn off the car and start it back up, it runs normal for a little bit. This problem has been getting progressively worse and now the car isn't driveable.
Also, when the accelerator is pressed hard from idle, there is a dip in the rpms. However, when in park I can raise the rpms to any level and it will stay there without fluctuating.

The computer is throwing the code P0108, the map sensor is showing higher pressure than expected. I have replaced the map sensor and all vacuum lines connected to the throttle body (they were in bad shape). After doing both of the above, the car seemed to work fine, then 30 miles down the road it was back to the same problem. After this I started throwing parts at it, and replaced the fuel filter, the fuel pressure regulator, and the spark plugs, I also cleaned out the throttle body. These had no effect. Just now, I used a baby snot bulb connected to turbo bypass valve to test for leaks, but it didn't seem to be losing vacuum.

I'm tearing my hair out on this one, and hope you can help. I have a feeling it's something very simple, but all of my research and attempts to fix it have been dead ends.

**RobRich** · June 21st, 2009, 11:52 AM

Welcome to TechIMO!

I am moving your discussion thread over to the community forum.

**RobRich** · June 21st, 2009, 11:56 AM

Got a boost meter? Getting any strange fluctuations? Creep? Spiking?

groker · June 21st, 2009, 12:39 PM

Yes (the built in one), the turbo seems to be running as normal. Have you seen this happen with turbo issues? Should I get an external meter to verify this?

**RobRich** · June 21st, 2009, 01:00 PM

I am not saying that is the problem, but considering the ECM was logging a MAP sensor error it could have been a bad sensor, or it could have been an actual manifold pressure issue like a wastegate problem or similar. However, if the turbo is spooling smoothly and within acceptable range, then it is likely okay.

Moving on, have you checked for vacuum system leaks with a vacuum check? I just noticed your comment about replacing vacuum lines at the throttle body. If they were in poor shape, it is likely many of the other vacuum lines are in similar condition. Vacuum leaks can present serious issues for turbocharged engines.

Curious, do have the ability to take a short clip of the problem, say with a digital camera or cameraphone? It can be a huge help if we can hear and see the problem.

groker · June 21st, 2009, 07:01 PM

Do you know of any resources that show where all of the vacuum lines are, as well as the expected vacuum pressure? I see the vacuum lines connected to the throttle body (4 lines) but I'm not sure where the rest of them are. I'm on my way to get a vacuum guage.

I have the Saab WIS software, but I'm not proficient in using it (yet).

I had ordered a OBDII adapter for my laptop, and hope that will shed some light on what's happening.

Here's a video of what's happening:
http://www.youtube.com/watch?v=TXj9gOWEtqc

groker · June 21st, 2009, 07:01 PM

sorry, duplicate post

**RobRich** · June 22nd, 2009, 08:45 AM

Not much idea on line placements or vacuum values, as I have yet to ever work on a Saab engine. I am carrying over basic troubleshooting ideas from DSM/Mitsu turbo engines.

You definitely need to get the OBD2 setup working, as that should open a wealth of info.

Just watched the video. Definitely pull a vacuum check. If it is losing considerable vacuum above idle, you might have nothing more a clogged catalytic converter.

However, since I am not too informed about Saab engine quirks, I suggest also posting your problem at the Saab Central forum.

Saab Forum : Forums for the Saab 900, 9000, 9-3, 9-5, 9-3SS, 9-2x & 9-7

RedFury · June 22nd, 2009, 12:08 PM

Yeah, it sounds like a cat gone bad to me after reading the thread up to this point.

The easiest way to find out is to pull a vacuum check...it's the poor mans scan tool for the mechanical side of the engine. I think the MAP sensor is essentially telling you this, but we tend to focus on the sensor instead of what the sensor is saying.

groker · June 23rd, 2009, 07:57 PM

Are there any negative consequences of pulling the catalytic converter? Other than pollution (no smog tests where I live).