Foolsbry

Hey everyone!

I've got a 1985 944, old style dash, and I recently discovered it isn't exactly water tight, had some rain leak into the passenger side footwell. I could see there was a tiny bit of water on the wiring, and a little bit on top of the DME box. The night that it happened it started fine, but a few nights later I was driving home and died at some traffic lights, car would turn but no tach bounce. I try and start the car the next day and it starts up and runs as normal, take it for a spin and everything seems fine.

Then today I go to start it again and it's no go once more. Cranks but no tach bounce. I go out and buy a multimeter to test the DME harness according to a video I found on youtube. This is later on in the day and I think, "might as well see if it wants to start now" and of course, it does easily. I still proceeded to remove the DME harness and give it a test, all the tests seemed to come up positive, so I'm a little stumped as to what the issue could be for it to start sometimes, but not always. I was inspecting the Fresh Air Blower afterwards as this is where the water had originally leaked in due to the plastic shroud not sitting flush against the body - another issue I have to fix.

I touched the shroud and noticed it was really quite hot, considering the fan hadn't been running at all. I was cranking the car for maybe 30 seconds in total during the test, keys were in the ignition for the last part of the test which required turning the car over to check the voltage. It just strikes me as odd that the Air Blower could be getting so hot from doing nothing, I have pulled the fuse to the air blower, so it isn't running any more and I had hoped that the issue was something to do with that, but since then it's still refused to start.

I've got a new DME relay from Focus 9 coming, the one with diagnostic lights on it, so hopefully that will shed a bit of light, but it's coming from the US and I am in Australia and a little bit impatient. If anyone has any clues on what else to look for to solve this problem they would be greatly appreciated!

Thanks,

Garth

Jfrahm

Of course you can try a DME relay jumper wire in the meantime: http://www.clarks-garage.com/shop-manual/fuel-05.htm

T&T Racing

Use advance search on rennlist , poster name "Acantor"and key words " not starting engine" to get ideas to help diagnose problem

walfreyydo

No tach bounce could be speed or reference sensors. Follow the walkthrough on clarks:
http://www.clarks-garage.com/shop-manual/ts-01.htm

Jfrahm

Sure, but the DME relay is a very common problem and IMO everyone should have a jumper wire (or a spare relay or at least know how to jam the relay). It's quicker to try the jumper wire than to even _schedule_ a flatbed.

walfreyydo

Agreed, however, usually with a bad DME relay you get tach bounce, just no fuel. Always good to have a spare, a jumper or just get a solid state! OP will be happy with the F9T DME relay, but if that doesnt solve the problem, next would be to run through the tests on clarks.

Jfrahm

In my experience the DME is disabled by a bad DME relay, thus no tach bounce. But I suppose in some cases the fuel pump half might fail independently.

walfreyydo

Actually looking back at the DME relay diagram, you could be right since it does send power to the DME and injectors. I guess it depends on which switch goes bad.

T&T Racing

A bad DME relay does not correlate to no tach bounce.