951 suddently stalling?

Yan · 06-18-2002, 09:47 AM

Hi!

Since about a month, I've had that kind of problem with my 951. The car runs really fine, the idle is right at 900 RPM and is stable, but once every 2 or 3 days the car suddently stalls. There are no factors; it happens at any time of the day, at any weather, in any driving condition (launching from a stop or rolling at 60 mph). The car doesn't start for about 15 or 20 seconds and then it starts perfectly, exactly like if nothing happened.

My air filter and my spark plugs are ok... Can anybody help me? I really don't know what could cause this.
Thanks

Scott R · Scott R's Garage

Had that same exact problem. I had a faulty alarm module.

Yan · 06-18-2002, 07:26 PM

Hi!

Scott: did the starter turn when you the car stalled and you tried to start it back? Mines turn but the car doesn't start. It doesn't look like an electrical problem. If you say so, then I'll check the alarm module tomorrow!

I've got an update for you guys. Today I stalled 3 times. In every case, it was on idle or when launching. It seems to happen more and more often, and the car doesn't stall as suddently as the first times. The idle becomes unstable for about 5 seconds and then the car stalls. It also takes more time than before for it to start back: about 30 seconds.

When it starts back, it runs REALLY great. I checked my DME relay pins today and it looks like it's been changed recently.

My fuel pump doesn't make any suspect sound. On my previous 944 the fuel pump was going bad and I know what kind of sound it makes. I don't smell gas neither, so it doesn't look like the car gets too much of it.

Would the first things to check be the fuel filter and the fuel pressure regulator? Is there any way to know if it is really the problem before changing these parts? I'll change the fuel filter as soon as I'll get the part, but before changing other parts I'd like to get tips in order to find the real problem.

Thanks!

Lawrence Coppari · 06-19-2002, 06:22 AM

You might check the sensors on the clutch housing that tell the DME where the crankshaft is during its rotation. My '86 turbo has plug in connectors that had gotten wet/oxidized and needed cleaning. However, mine caused a starting problem, not a stalling problem.

Scott R · Scott R's Garage

Check the wiring harness to the AFM. They wear against the side of the block and short to the block sometimes. And yes when I had this problem my starter would still work, and usually it would start right back up after I turned the key off and then back on.

Yan · 06-20-2002, 04:55 PM

Hi guys

Today, I did some tests with my car in order to get more information about the problem. The car is ALOT slower at high RPM and high speed. Before, it took beetween 6.1 and 6.7 seconds in order to make a 60-100 mph sprint. Today, it was more like 10 seconds. I barely pulled on a Corvette L98 even over 60 mph, which is really weird.

Also, the car only stalls at idle. The idle is perfectly stable and the car suddently stalls without any sign. When rolling, everything is stable too. I ordered a fuel filter today and I'll change it tomorrow.

Scott R · Scott R's Garage

Is it a sharp electrical type cut off? Or is it a sputter and die like fuel starvation?

Yan · 06-21-2002, 05:12 AM

The car dies like fuel starvation. Then, when trying to start it back, the starter turns but the car doesn't start.

no1biscuit · 06-21-2002, 05:35 AM

I had a problem the other day that mine started spuddering (fuel starvation) and even sometimes completely die. It was the fuel pressure regulator..... Just a thought