Car dies while decelerating

[BrianW]

Hi everyone! My Sport/Combi (wagon) dies while slowing down. From 75 mph, from 20 mph, from 40 mph, doesn't matter. Only happens when the car is fully warmed up. I have installed a new MAFS, new coil packs and new plugs. Car runs a LOT better, but still dies. No check engine light. It was on before the replacement parts were installed, but not now. From reading here on SAABWORLD, a crankshaft position sensor is a possibility, but others have tried it and not solved the problem, so I'm wary of that. All help would be greatly appreciated!!

[Digger]

Sounds like the only two things you haven't done are the ION module and the CPS. Either, or neither could be the cause and so could the ECM, no answer do have a couple of questions.

How often does this happen, every time, or occasionally?

When the car dies are you able to restart, that is will the starter motor crank the engine immediately after the stall?

Do you need to pull a fuse or disconnect a battery cable to get the car to restart after the stall?

[BrianW]

Sounds like the only two things you haven't done are the ION module and the CPS. Either, or neither could be the cause and so could the ECM, no answer do have a couple of questions.

How often does this happen, every time, or occasionally?

When the car dies are you able to restart, that is will the starter motor crank the engine immediately after the stall?

Do you need to pull a fuse or disconnect a battery cable to get the car to restart after the stall?

Car will restart immediately, I do NOT have to undo the battery. It happens very frequently, always when the car is at operating temp, never when just starting or the first 20 minutes or so of driving. Thanks for your help!!

[swisssaabist]

Could be throttle body failure your car is with TCM ?

[Digger]

Doesn't matter whos name is on the car, Buick, Chevy, Cadillac or Saab, the crank position sensor (CPS) is the most common cause for this kind of shutdown without a code. When the computer doesn't see this signal it thinks you wanted to turn the car off and doesn't consider this a fault. The CPS is a magnetic pickup and magnets get do weak with heat, you can fight an intermittent thermal sensor for months of daily driving before it gets bad enough to trip a code. All the different years of Ford, Chrysler, GM have their most common cause for this problem and luckily our most common cause is a part that is easy to replace. It may not seem like it while you are changing it, but compared to where the CPS is located on GM's bullet proof 3800 V6, replacing our CPS is a piece of cake.

There are a couple of fuel related parts and a couple of modules that can do this too, but the CPS is the most likely cause, the part is less than $50 and with ramps or jack stands and a good socket wrench set you can do this at home. Laying under the car and using air tools it took me about 3 - 4 hours to replace my sensor. Wasn't my first CPS sensor and with air tools it shouldn't have taken more than an hour, but with my shoulder torn and my arm strapped to my side I was working one handed. First time doing something always takes longer, if you're working with two hands, your first time shouldn't take you any longer than it took me and probably won't take you half as long.

If replacing the CPS doesn't fix the problem, it's not wasted time or money. These things go bad with age as well as with use, so if you didn't need the sensor today, it was only a matter of time before you would and now you've reset the clock.

Fuel pressure can also cause this kind of no code shut down, checking fuel pressure on a hot engine can be risky even with the right tools, so if you don't have a pressure gage you can leave in place while waiting for this to happen, I suggest referring to someone who does.

CPS is most common cause, loss of fuel comes next, everything else is third.

[BrianW]

Thanks, digger. I've seen the CPS replacement videos, and with a bad back and no jack stands...... I'll see if I can borrow some stands and give it a shot!