'87 951 randomly dies while driving.

[Tom]

I don’t see the photo upload so I’ll try again and forgive me if it’s a double post.IMG_3290.jpeg

Unless my eyes are playing tricks on me, the thing you are holding in that picture is the wire to the turbo aux water pump. It tells the aux pump to go on when the coolant at the turbo is too hot. Worth fixing that wire, especially if the wire itself under the sheathing is frayed, but it's not a vacuum line and wouldn't have any impact on starting the car.

Check for tach bounce next time it won't start.

[Tom]

If that doesn’t stop it’s misbehaving, cure the DME. Install a solid state F9 unit and be done with it. Whatever’s left over is another issue at hand.

These cars like to be diagnosed systematically.

See post #3. He already has that relay.

[Tom]

That kinked temp sensor hose is a classic vacuum leak. It would absolutely cause cold start problems. The rough road probably jostled a bad electrical connection loose, which then temporarily fixed itself. You found your culprit. Replace that hose.

We must be looking at different things. He seems to be holding the wire to the temp sensor, not a hose?? Or am I missing something in that picture?

[Jinman3]

That kinked temp sensor hose is a classic vacuum leak. It would absolutely cause cold start problems. The rough road probably jostled a bad electrical connection loose, which then temporarily fixed itself. You found your culprit. Replace that hose.

We must be looking at different things. He seems to be holding the wire to the temp sensor, not a hose?? Or am I missing something in that picture?

Holding the wire to the temp sensor! It….. it doesn’t feel like it’s connected at all but I didn’t pull off the tape to verify. I’m able to put my nail between the wire however, would soldering the connection be the repair here or will I need to pull out the wire and replace?

And yes, I have a F9 relay with diagnostic.

[Jinman3]

Sounds good. Check for tach bounce. The sensor's are the next most likely thing...

Tried to take it to work this morning and it died around the block. The tach bounces but once the car died, the tach went straight to zero if that means much.

[Tom]

Sounds good. Check for tach bounce. The sensor's are the next most likely thing...

Tried to take it to work this morning and it died around the block. The tach bounces but once the car died, the tach went straight to zero if that means much.

The key is to check for tach bounce or twitching while you are cranking the engine if it is not starting. If you are cranking away, and the tachometer is completely motionless, that's a good indicator that your speed in reference sensor wires are frayed under the rubber boots. You can also try wiggling or rattling those wires when the car won't start, and often you will get lucky enough to at least get your car home. Also, when the car will not start, turn the ignition on and check to make sure the boost gauge goes to about one. That is a rough proxy for whether or not the DME and KLR are getting power.

[Jinman3]

Hey all, after a quick visit to my wife in Canada I am back home and able to do a bit more troubleshooting. I watched and read up quite a bit with ignition coil and distributor cap and rotor issues. I attempted to use a multimeter to test the coil and believe it is bad based on the values I received (granted I couldn't get a value a couple of times when trying which was strange or a reason that it needs replacing).

I pulled off the dizzy cap and saw quite a bit of pitting on the connections and on the rotor. I'll try to attach some photos here.

[Tom]

Have you pulled a spark plug wire and checked for spark?

[Jinman3]

I bought a spark tester from harbor freight and checked each plug and they didnt trigger the test light.

[Jinman3]

Update: car runs now. After pulling off the distributor cap and reinstalling, I think the issue was because I didn’t properly reinstall in last time with the hooks. So I did the spark tester for all 4 plugs and had consistent spark for them all.