The symptom is that it will start, RPMs go to 1000 RPMs, then promptly dies?

CMEENS

MEMBER
1997 SAAB 9000
4 CYL
FWD
MANUAL
130,000 MILES

Ive got a 98 Saab 9000 aero 5 speed, with 130k on it that will not run. The symptom is that it will start, rpms go to 1000 rpms, then promptly dies. If I pull the MAP sensor plug, the car will idle at 1,000 rpms all day long, but will rev to about 3,000 and then die. I replaced the following:
Di cassette, MAP sensor, plugs, fuel pump, fuel press regulator, ECU, fuel filter, apc was inspected, crank position sensor, tested the wiring from the ecu to the fusebox, to the DI, to the crank pos sensor, apc, and fuel pump, most of the hoses to include those to and from the turbo, both oxygen sensors.
I am showing no fault codes except when I pull the MAP plug. If I pull the MAP plug, start the car, and hook the MAP back up with it running, it will idle fine for about 10 min, then die. I have talked to several “experts", including some that specialize in SAAB’s and they are all perplexed without me brining them the car. The problem is I am 250 miles away from the nearest shop that can work on it. I cant drive it around the block, but it idles just fine with that plug pulled. I am desperate for some advice I am fairly mechanically inclined, but this has me completely lost. Thanks!

5 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

It sounds like to me that you have a clogged exhaust system, either the cat has broken apart and clogged or the particles from the cat has clogged the muffler. The way to confirm this failure is to raise the car up and then take a rubber mallet and softly stick the catalytic converter and muffler to see if you can hear anything rattling around inside the two. This will let you know if the cat is bad, Also this guide can help, it will tell you to disconnect the exhaust in front of the cat to see if the engine will rev.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

The diagrams below we show you where to undo the exhaust system. Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

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Tuesday, April 27th, 2010 AT 6:52 PM

CMEENS

MEMBER
4 POSTS

Thanks for the reply. The fuel press regulator has also been replaced, as well as the fuel injectors and the fuel pump. I am not sure what the temp sensor has to do with it. Is this the temp sensor below the intake manifold? I checked continuity between the MAP and the ECU as well as the ground to the MAP, and it is good. There is a temp sensor just before the throttle body, but I do not think it is a factor. The car does run better with the intake removed. It seems to have troubles with any positive air pressure from the turbo. Idle speed is where it should be as long as the MAP leads are disconnected. There is no CO adjustment that I know of on the SAAB 9000 that I know of, and I have power to the ignition cassette during start up and after the engine dies. Fuel pressure is within tolerance.

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Wednesday, April 28th, 2010 AT 12:12 PM

BMRFIXIT

MECHANIC
19,053 POSTS

Disconnect and check the way the engine runs to see if I am correct please?

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Wednesday, April 28th, 2010 AT 12:53 PM

CMEENS

MEMBER
4 POSTS

Thanks again for the quick reply. So I tried what you said and I started it with no problems and drove it around about a mile without issue, thanks for your insight. This site is great btw. I should have done this earlier

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Wednesday, April 28th, 2010 AT 2:50 PM

BMRFIXIT