I all, I parked my 86, 944 turbofor the winter, went to fire it up today, and it wouldn't start. Ran like a champ last year. It will spin but won't fire. The tach bounces slightly when you try to start it. By that i mean, it bounces initially when you first hit the key but dosen't continue bouncing when you are holding the key to start. My thought is that i should be able to hear the fuel pump and i can't. I checked under the hood and all i could find is a 15amp fuse for the fuel pump sender in slot 37 (if i remember correctly). I could not find a relay. Any ideas?? Thanks!!

 

There is a fuel pump relay near the drivers side rear of the fuse box. I can't remember what the block number is. It is a square black relay. The back of your fuse cover panel should show you the location.

 

I finally got my new DME relay, replaced it, and still nothing. It will spin, and the tach shows 2500 rpm when spinning. The thing is, when i jumpped the 2 spots (can't remember the numbers now) when the relay was removed, i was sure that the fuel pump started. Now with a new DME, nothing. Any ideas???

 

I would check your speed and reference sensors next. The tach should not be jumping to 2500rpms, that seems like an issue there, or with a ground somewhere.

 

Before when i tried to start it, the tach would bounce slightly, now with the new relay, it goes from 2000 to 3500. I will check some grounds today. I will also check the forum for checking/changing the speed and reference sensors. It just seemed strange that it worked perfectly until i stored it for the winter.

 

Try giving the DME itself a good kick (well the passenger floorboard, not the dme itself, lol). Maybe there are some broken solder joints on the board.

 

Ok, i finally got a bit of time to tinker again. I made a mistake when i said the tach jumped to 2500 when starting. The tach DOES do that, but only when i had the booster/charger on the car. When i disconnected it (after the battery was charged), the tach bounced ever so slightly when i initially tried to start it. It does not bounce during the duration of the car spinning, at least not enough for me to tell. I disconnected one of the lines coming from the fuel rail and there was lots of fuel in it. I didn't have a second person to help spin the car so that i could check that and the coil. Another question, where is the fuel pump located and does it have its own ground?

 

Update - I found someone to giveme a hand with starting the car. No spark and no fuel. So being that i changed the DME relay, the fuse is good, that leads me to think that it is the computer itself. The possition and reference sensors shouldn't play a factor with this senario should it?

 

Update 2 - OK Finally think i made some headway. I went back under the pass foot compartment to check a few for an alarm, i pulled the rug back to get that black mounting bracket thingy out of the way.... To my horror the underrug backing was SOAKED, drenched. I read another post that someone had the problem of water getting in and blowing his DME. I took the computer out and opened it, and could not see anything that looks burned visually other than a few small black (smokey like) marks on some of the circut paths. (Please forgive my descriptions, i'm a welder ). Obviously water got in somehow. Is there a spot on the 944s that need attention as far as water sealing? Is it safe to wrap the DME and the other unit beside it in plastic? How hot do they get? I am going to order a new computer as i am fairly sure that is the problem. Any opinions?

 

More than likely your battery box tray has rotted. You will need to pull the glovebox, and get a flashlight and look under neath the dash (above the DME) at the metal pan, and see if you can see any traces of water or rust holes. If you find them, then you need to either weld in a new battery box, or if it isn't too bad, pull the battery and coat the entire tray with POR 15 which should seal it up.

I just had to go through the same thing. I fought a leaking tray for years, and finally I got tired of it and cut the tray out, and made a new tray for the car.

If you pull the dash, you should be able to weld in a new pan.

You can also pour a gallon of water in by the battery tray, then get underneath the dash quickly and look for leaks.

That would definitely be the cause of your no start.