Engine Died While Drive - Will Not Start

[beren]

Thanks everyone! It was the DME relay. I replaced with with one from the host and she started right up and runs normally again!

The DME relay in the car looked original. The hardest part was getting the nut off without shearing the bolt off. Little WD40 and 15 minutes loosened it up.

Definitely something to keep in an "oh sh--" bag - should maybe have a sticky thread for suggestions on what to keep in that.

I pulled apart the old one and didn't see any obvious issues. A pretty delicate device with those little switches.

[gwinnch]

It's good you've ordered a new dme to try, you need a spare for the glove box anyway if that's not it.

I had no start issues on my 85 a while back and ended up replacing the speed sensor for a couple of weeks of running then repeated the no start yielding a bad reference sensor. Replaced it too, running fine since then (many months, now).

The No. 1 "no start" troublehooting item I gleaned from lots of pp forum searching and reading:

Check for spark before you start buying parts or checking fuel.

[gwinnch]

Didn't see your last post before I sent mine in, glad you found it. Get another for a spare!

[pmax]

Originally Posted by beren

Thanks everyone! It was the DME. I replaced with with one from the host and she started right up and runs normally again!

You meant the DME relay not the DME.

[beren]

Originally Posted by pmax

You meant the DME relay not the DME.

Yes the relay - updated my post above.

[JJ 911SC]

Originally Posted by beren

Yes the relay - updated my post above.

Great, now you need to re-order as one should always have a working spare in the glove box.

Small price to pay for those DME car.

[911obgyn]

When you get the spare relay pop it in and check it so you know it works before you put it in the glovebox. get some fuses while you are ordering, its also handy to have a window switch.

[beren]

Carry a full set of fuses already. I'll have to add some more tools like a 10 mm box wrench that you need to change out the DME relay.

[Walt Fricke]

The usual failure mode of these DME relays is a cracked solder joint. The circuit board, with its heavy relay coil, is held to the board into which the wire connector plugs by various pins soldered in. The vibrations of the car, and the up and down motion of the coil board, can eventually crack one of these soldered connections which carries current or ground or the like. You can test with a multi-meter to see which one is bad. You can just reflow/resolder all of them just to be sure. Then test it - it should work. If you put a piece of foam between the bottom of the relay board and the case, it should support it and might prevent this happening again. Then it can be your spare. Of course, if the contacts are all pitted and burned, or one of the tiny wires which energizes the solenoid coil is broken, maybe it is for the dust bin.