This is what happened:
My early 944 (85) was behind a red light, but then as i wanted to put the car in gear, the car just turned off. I tried turning the car on, but it just cranks but doesnt run.

Here is what I have checked and they all seem to work.
-fuses
-DME Relay (jumper and the spare)
-DME (put in a spare/maybe the spare doesn't work?)
-Spark Plugs fire (went ahead and changed the spark plugs and a spare coil)
-reference and speed sensors (both show the ohms between the range on clarks-garage, replaced with my spare set anyways)
-Getting 36-37 when jumped or when cranking. I even pulled off the fuel inject. rail and put cups under each injector and had a little fuel there after cranking.
-12v at battery
-shot starter fluid down the intake, and it still wont start.
-the only thing that seems funny to me is when i pull the injector terminals off, and measure each slot against the ground it gives me ~ 12v at both slots, and on clarks-garage it says one is suppose to be 12v and the other 0v. Could that be the problem?

I am all out of ideas and hate this car right now.. any ideas?

 

You might want to try replacing the Distributor Cap. I was having the same problem, my car would crank but wouldn't start. I just put on a new Cap and it started right up.

 

The injector plug should have 12V on BOTH connections with the ignition on. The DME pulses ground on one of them to provide the 12V differential to fire the injector. Sounds like yours is OK. You can get a noid light to test for a pulse. This is an LED that plugs into the connector on the harness. It should glow when the engine is cranked. Mine was made for Bosch injectors And it was about $5 at Autozone.

You might want to check for spark while cranking. I use a timing light for this.

 

distributor cap is about 8 months old, and spark gets to each plug, i pulled out the plug and saw spark on each and even got new ones because the old ones were dirty.

 

yeah, my next move was the noid light. But i am getting spark at the spark plugs, each one of them. Having my brother start the car and checked each spark plug and they all sparked? The only other things that are left i think are compression and timming to me. That makes very little sense though because it just stoped at the light.....ahhhhhhhhhh

 

If you've confirmed spark and it still won't fire with starting fluid, that suggests that the spark timing is wrong. DME controls that based on the signal from the refrence sensor. Even without that signal, you will get a spark; it just won't be timed correctly.

How's the condition of the plugs for the sensors to the harness - that was the problem with my early car; they even looked OK, but when I unplugged the sensors, the connectors crumbled.

Other things to look at are the rotor (has it slipped or is it loose?) or cap.

 

do the gauges bounce when you crank?

 

Gas? Does your fuel pump run? Do you have a full tank of gas? Do you have a way of checking fuel pressure?

Just my .2cents

 

Uh oh. A lot of people lose the timing belt at a stop light. Did you check to make sure your timing belt isn't broken? I hope this isn't the case, but check it out.

 

okay, well I am just about to throw in the towel. I again checked my fuel rail today had good pressure, even removed it and saw the injectors spitting out fuel into their slot on the intake. I even shot starter fluid down the intake and the injector holes and no start or even hesitation to start. So I am certain it can't be the injectors or a fuel related problem. Now, that leaves me with a spark problem but i see spark at each spark plug, with a inline tester AND even taking them and checking against the ground.

I checked my speed and refrence sensors again today, and they show good resistance and even took them out and checked for visual problems. (have replaced with spares already) would they cause a change in timming if not working properly or just cause a no spark situation?

So with that said, what eles could it be? Timming? compression? Isn't it odd to just lose compression at a stop light? or even timming for that matter? The distributor spins so I am pretty sure that the belt isn't broken...

Any help/ideas? It will be greatly appriciated...

 

Maybe you should take a look at some other stuff like the throttle position sensor and AFM. Clarks Garage has proceedures on checking these. I don't know if these could cause a no start, but worth a look. There is also a DME temperature sensor that enrichening the mixture for cold starts. Again, I don't know if a failure would stop a running engine.

If you want to check timing, hook up a timing light and shine it in the inspection hole in the cam sprocket cover. The actual timing is controlled by the DME and is non-adjustable, but my DME failed and caused the spark to go away. That is how I found it.

 

I second that

 

If you are getting spark at each plug (not the same one 4x as often) then the cambelt is still turning. That's good news. Timing may have slipped, that can cause a no start or a weak running engine, or an engine that almost starts but not quite.

It'd be good to check it, as if it's slipped it might not have bashed valves yet, but when it slips enough it will.

Does it sound weird when it tries to start? Spin fast and sound like a sewing machine?