What's that smell? Wait, and why isn't my car running?!
 

I'm driving along some country roads, enjoying my newly functioning blinkers, good engine temps, and dialed-in suspension, when I start to smell something slight...Smells like something electrical releasing smoke or a hint of plastic burning...I check around the cabin and in the rearview for any signs of smoke (none), and then the motor dies rather suddenly, in motion.

I pull off to the side of the road and start looking around, smelling electrical components like a crazy person. Nothing seems particularly fried. The car turns over with gusto, so I don't think it's alternator/battery. No fuel smell; tank half full. I got the car towed home so I can start poking around tomorrow.

I replaced the DME relay with a genuine Porsche sucker maybe a year ago. I guess it could still have failed, but I'd be surprised. It did feel warm, but not hot. Motronic did not feel particularly warm. I can't here a fuel pump turn on with the ignition, but I'm not sure I ever could. I suspect the fuel pump or fuel pump relay...My pump is below the gas tank.

The motor is a '95 3.6. Any guesses? Anyone gone through this with a good air-fuel-spark checklist?

Damn thing was driving so well. At least it chose a nice spot by a lake to break down.

http://ensaster.com/pics/vehicles/sm...-breakdown.jpg

Ugh...nothing to add but grief and sympathy. Your car is nice, hope you get it back on the road soon.

-Steve

Ignition units are a weak point, as well as bosch silver coils.

When my heater motor brushes wore out, I got smoke in the cabin.
It was that dreadful electrical smell that instills deep rooted fear.

If the fuel pump burned out, I think the smoke could make its way into the cabin.

Maybe you can try the fuel pressure test.




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As John said ignition final stages and coils are suspect but I think I'd start poking around near the ECU guessing it's mounted under the seat during the conversion and you had the smell inside
the car. If some "magic smoke" has escaped you'll see the cause.

When you say "ignition unit", what is that exactly? The switch with the key?

Turns out this car has no fuel pump relay—it's in the DME, duh. I pulled it out, sniffed it, checked for bad solder, and put power to it and it's clicking when it should. When I manipulate it manually in situ, the fuel pump spins up strongly. It does not when the key is in the position just before starting the car.

I pulled the Motronic, opened it, sniffed it...Looks clean and undamaged.

I'm about to wander down this list, though it makes no mention of coils...

Porsche 911 Engine Starting Troubleshooting | 911 (1965-89) - 930 Turbo (1975-89) | Pelican Parts DIY Maintenance Article

check to see if you are getting spark.

I smell fuel in the engine bay, which suggests that fuel is getting there when I try to start it...

DME wiring test...With the ignition off, I have power to pin 30 (direct from battery). With the ignition on run I have power to 30 and 86. I believe this means the ignition switch is good, right?

https://dorkiphus.net/porsche/attach...5&d=1206400894

I smell fuel in the engine bay

Like T77911S mentioned, how about the quick basic checks like spark (it sounds like you're getting fuel for the most part). Pull out a plug and see if it sparks.

I couldn't fit my spark plug tester on it, but I pulled one of the wires, stuck an extra spark plug in it, ground it against the AC compressor bracket, and turned the car over...No spark.

Inductive timing light.......
 

Tremelune,

A convenient and efficient way to test for ignition spark is using an inductive timing light. No need to remove or install spare spark plug for the test.

Tony

With the ignition on run, I have power to all four wires at the ignition coils...I guess I'll test those out.

Forgive my ramblings—Besides my astoundingly simple CB350, I don't think I've had a no-start condition in a vehicle in a decade. This is pretty much my day, so I'm researchin' and poking around...

Maybe the smell was a red herring and some passing car had their handbrake on...

Odds of both coils failing at the same time?

I'd think kinda slim.

That's a good point. I was just down a rabbit hole of investigating the possibility of a broken distributor belt, but the car would still run.

Perhaps it's just a blown $1 fuse. Have you checked them ?

Good luck !

Fuses look good. I gave them all a twist...I dunno what they affect, though. Everything seems to be getting power.

I'm looking into doing a more comprehensive test of the DME/wiring, I'm just kinda poking around in the dark, though.

They definitely will run on only one coil... not well, and its not particularly good for it, but an engine that won't run on one coil has more trouble. Maybe a broken distributor belt or a bad coil. etc.

look up the pin out for the DME harness plug, and check for 12v power, with key on. If the ECU has power, then pull a plug wire and check for spark. If there is spark, jump power to the fuel pump and see if you can hear the pump running. If the fuel pump runs, leave it jumped and try to start the car.

Also, pull the caps off the distributor and make sure the belt is intact. It SHOULD run without the belt, but you could have compounding problems.