Hey guys, I have a frustrating problem with my spec 944 and I thought I would ask your advice before throwing more money at the problem. Trust me I have searched all the internet forums for the common 944 non start issues but I know you guys might be able to point me in the right direction since I'm new to 944's in general.

Ok so the car has been sitting in my garage for quite a few months, but every few weeks I'll start her up just to run the engine for a little. I have never had a problem and surprisingly it has always started up on the first try without a single hiccup. But this most recent time all it would do is crank but not turnover. Which is weird because what could have possibly changed all of a sudden?!

So my first step was to see if it was getting any fuel. A quick loosening of the fuel rail screw and it seemed to be getting fuel. Next I used some starter fluid in the intake and it runs for a min. I also had tach bounce so I figured my speed and ref sensors were good.

So my next step was to order a new DME relay and fuel filter. While I waited to shipping I switch out the DME with a spare I had and all of a sudden the car would start! But..only for a few seconds and it would die if you gave it any gas. What's weird is now I have NO tach bounce...As soon as I start cranking the tach stays at 3k. This leads me to think I messed up some wiring under the hood or under the dash when fishing around and changing out the DME. If I put the old DME back in I don't get any tach bounce like I did before but it still won't start.

So it really boggles my mind that it will start with the new DME but now no tach bounce. Seems electrical/sensor related right? I haven't put the new fuel filter in yet as that doesn't seem to be the problem from the sequence of events I've had.

I will post a video tomorrow but if you guys have ANY suggestions I am all ears!

Thanks again!

Wiring problem or DME issue. Rember though you need to match a late DME to late AFM and early DME to early AFM. The difference is voltage range from the early vs late AFM. Make sure you have the same DME.

If you do not have an AFM signal the car will start on the starter, but shut off right away. No tach signal is a sign of speed/ref sensor errors.

This not an easy problem to fix, but you will need to go after the wiring as it really sounds like that is a problem. The DME has its own harness that runs from the DME plug to the speed/ref sensors, AFM plug, ISV plug, Temp sensor for DME and temp gauge, oil pressure gauge and fuel injectors. Breaks in this harness mean trouble. The DME relay is not connected to the harness or the DME directly. This sounds a little strange, but and right now I can't remember how the DME gets power, but I do know the DME harness is seperate from the body harness as I have removed and replaced a it a time or two. Anyway these wires can get damaged from the heat of the engine bay and look ok, but fail when wiggled. Any number of these wires can cause a failure.

Thanks so much for the info! Very helpful. Ok so I think the main problem then was the DME. You are right my AFM is not matched to the spare DME I replaced. I switched it with a 88 DME and it has an early AFM. Do you think this would fix the tach problem too though? I guess I'll find a late AFM and go from there?
Thanks again!

UFfitz56 wrote:


That would explain why it would not run with replacement DME.