944 Turns, but wont start (Please help!)
 

Hey everyone, I have a question I want to run by you guys to see if anyone knows of a potential problem before I hand it over to my mechanic.

I drive a 1986 944 N/A as a daily driver, car has been starting every day without problem and has been a fairly reliable car. NOTHING out of the ordinary has happened in the past week with the car.

I come out of school to start my car and it starts up without drama. I sit in the car for about a minute checking emails/letting it warm up when all the sudden it just dies. I get the "idiot light" and a dinging noise. I turn off the car and start it again, car just turns over but doesn't fire. I put a gallon of gas and check all the connections, still nothing.

I'm thinking it could be dirty fuel lines, bad spark plugs, or a faulty DME relay. But I still don't understand why it even started and then shut off, it's not like ALL my spark plugs and fuel lines would quit at the same time. The car didn't show any symptoms off a loss of power or a weak turn over the days before.

I'd also like to add that my car has been making a faint hissing noise while the A/C is engaged. I've traced it down to vacuum lines that need to be replaced. Could that prevent my car from starting?

I really need some help quick, my poor 944 is sitting out in a big parking lot all alone...:(

Potential problem?

DME
DME Relay
Fuel Pump
TPS
Speed/Ref Sensors
Injector harness
Distributor
Coil
Battery

Hard to narrow down with no information. Do you have fuel pressure? Spark?

Battery was replaced a week ago. I'm starting to lean towards reference sensors from what I've heard. Have not checked fuel pressure, what's the best way to go about doing that?
EDIT*
I found some ways to check if the fuel pump is working and I'll be bringing my pressure gauge out to see if pump is working. Would a fuel pump just quit working while the car is running though? the car never showed signs of misfires or running lean.

I had the same issue, i ended up having to replace the following:

-DME
-DME Relay
-Ref Sensors

It took me a couple tries to get a good DME, the first three were bad, but the fourth one was perfect.

My money is on the DME relay. Jumper terminals 30, 87, and 87b on the relay socket. This will power up the DME and Fuel pump and unless the reference sensors are bad, the thing should fire up and run. If it does, you have a bad relay. Do NOT get a URO made one, they are crap.. I bought a new one a year or so ago and it lasted about a month before it started cutting out. Junk. When you jumper the terminals on the socket (30 is battery power, live all the time) 87 and 87b are the fuel pump and DME (I can't remember which one is which). You will hear the injectors click once and should be able to feel the fuel flowing through the fuel rail on the intake. If you can hear the pump running or feel the fuel going though the rail, the fuel pump is fine. Be sure to un-jumper things as the fuel pump will run the battery down in no time if you leave it connected.

Thanks guys. Got the problem fixed a few months back. You're both correct, I replaced the DME and crank position sensors and haven't had a no-start problem since.