Engine Stalling

[Targa Me]

Hello Everyone, I need your help.
I have an 84 Carrera 3.2 stock. The car has 138k on it. Was running just fine when all of a sudden the engine stalled. I fired it back up and it started right away, but stalls again within 20 seconds or so.
I replaced the DME relay with a known good one.
I checked and cleaned all the fuses.
I replaced fuel pump, fuel filter and check valve.
I have checked the grounds and everything is clean and grounded.
I don't know what to check next.
Any ideas??

[Mitch Leland]

I'm far, far from being an expert, but I'm guessing it has to be either lack of fuel or spark. You certainly can take a spark plug lead out and ground it to see if you have spark while turning the engine over. That might help you narrow your problem down, also you've given the knowledgeable members something to work with.

I wish I could offer more advise...

[dshepp806]

Verify coil is ok (while you're assessing spark conditions)

[Targa Me]

coil checked out okay. there isn't a spark issue; the car starts right up after stalling.

[ischmitz]

Good points about the engine needing fuel and spark. Did you do anything that lead up to this condition? Does the time to shutdown vary depending on whether the car is at idle or at higher RPM?

Here are some wild guesses:

- Bad DME (resulting in no spark/fuel)
- no fuel (maybe you are pulling a vacuum in your gas tank)

Cheers,
Ingo

[Targa Me]

When the engine stalls, it does not react as if it is running out of gas; it acts like the ignition is turned off just like it would if you were to turn off the key.
I tried replacing the ignition switch with a known good one - engine still stalls.

[ischmitz]

Well, spark is a pretty simple afair with the 3.2 Motronic: +12V to one end of the coil and GND controlled by the DME to the other end. Once the coil is switched on it stores energy and when it is switched off a spark is produced.

The DME receives the speed and reference signals from the flywheel sensors and produces the spark signal.

Do you have a friend that can run your DME in his car to see if the problem is caused by the DME itself? Where in SoCal are you located?

Ingo

[Newsboy]

How did you check the coils? Even if they test within Porsche limits with a multimeter, they can still have an internal fault, and cause problems.

[Targa Me]

The coil was checked per Bentley manual. Voltage and ohm values were according to spec.
I check it but didn't expect it to be the problem. In all my years and a mechanic I have never seen a bad coil. But there's always a first.

[stlrj]

Once you get it to start, try tapping on the DME relay to see if that is causing the stall.

Cheers,

Joe

[Thrlls]

Targa Me,
Did you ever solve your problem?

I'm asking because I'm experiencing a similar problem and I hope someone can direct me to the right direction.

When cold, my car will start right up, but if I don't throttle it a bit it will shut down. Once I give it a few taps on the throttle and hold a steady idle, I can take my foot off the pedal and the engine will idle ok.
However, when I drive down the road and come to a stop, the motor will shut down again. This will only happen when the car is cold. No problems restarting at any time.
I installed a SW chip and tried turning up the idle per SW chip instructions, but still the engine stalls. This is on an '84 3.2 and I also changed the 02 sensor and spark plugs.
Once the car is warm there are no problems.
It almost seems like my car is running rich, but I thought the DME would make the adjustments?? I can see some black soot on the side of my car where the exhaust tail pipe is, not sure if this means something or not.

Any ideas anyone?

[Targa Me]

Thrlls,
No I haven't fixed my car yet. My problem is very mysterious. Sounds like your problem maybe the Idle Control Valve. For a quick check, remove it from the car and shake it. You should hear some kind of rattle inside.

[Thrlls]

Originally Posted by Targa Me

Thrlls,
No I haven't fixed my car yet. My problem is very mysterious. Sounds like your problem maybe the Idle Control Valve. For a quick check, remove it from the car and shake it. You should hear some kind of rattle inside.

I'll give it shake, but wouldn't it affect my idle all the time if it were the ICV?

Mahalo

[Por_sha911]

Check for a vacuum leak (think about how it runs rough when you take the oil cap off).

[Thrlls]

While removing the ICV, I noticed the clamps on the hoses were not tight enough. I removed the ICV shook it...it rattled, but I still cleaned it out with some throttle body cleaner, put on new clamps, tightened them down...and walla!
No more stalling.
Turns out to be a dirty ICV and loose hose clamps.

Thank you for the help!