doug951

Hey Guys,

After a winter of the car sometimes starting and sometimes not, my 1986 944 turbo will not run at all. Here is what I know.
The fuel pump does not run when the ignition is on.
The fuel pump sender fuse is not getting any power.
I took out the DME relay and jumped 30 and 87B. The fuel pump started right up and there was 12 volts at the fuel pump sender fuse.
I then hooked up pin 30, 87B and 87 in the DME relay and tried to start the car. Nothing. It cranks just fine but just doesn't catch. The fuel pump was running though. I have good compression and am getting spark.
The tach bounces slightly while cranking.
I thought my DME relay was bad but now I am not so sure. I have two DME's and have tried switching them but no luck, one has never been opened and looks brand new.
Any idea's on what is going on? It definitely seems electrical in nature but I just can't pinpoint on what is wrong.

Thanks

blown 944

with those things said I would look at the injector clips and harness. What happens is the dme grounds the injectors to fire them and if they become grounded at the wrong time (short) it reverses the system (for a lack of a better explanation) and then they need to be grounded again to get it to fire them.

To absolutely eliminate ignition spray some starting fluid and see if it kicks.

doug951

Thanks for the response and you have definitely have me on the right track. Here is the update.
I pulled off an injector clip and hooked it up to a NOID light, and tried to start the car. The injectors are receiving a signal to fire. The car actually starts this way, runs really rough (on 3 cylinders). I've read on here that symptoms like that means the fuel pressure regulator has failed. So I bought a new FPR and still won't start. The thing is though it will start everytime I have the NOID light in, and once I take it out, the car will start once but die immediately. Then the car will not start again. So it looks like I have an electrical issue because the car will only start if the NOID light is in. Ever heard of issues like this? I don't really know where to look now. Thanks

blown 944

Probably the injector harness clips. They get brittle and the wires end up touching. I clipped a good injector harness off of an NA and soldered it into my red car.

See if you can pull back the rubber and see exposed wiring.

I suspect that with the Noid light you are actually resetting the circuit and then it will fire.

Spidey944

I always heard that if the car starts on 3 injectors plugged in, but not 4, it's the FPR that's the problem......

doug951

Ok so the car started this morning.
Here is the story.

Using a long screwdriver to amplify the noise the injectors make when they are firing, I was turning the engine over and my dad heard all the injectors firing. After all that, we took out a spark plug only to find that it is bone dry. There is definitely no gas getting to the injectors. So following Clarks Garage I test the fuel delivery rate out of the FPR return line, and it is over 1000ml per 30 seconds. That was higher than the 850ml clarks said it should be. Is this a concern? I got the fuel pump to run by bypassing the DME relay. I figure than maybe the DME relay is sending a weak signal to the fuel pump, so I put the relay back in, and start turning the engine and she fires right up. I reconnected every back together and it fires right up not even a slight hesitation. I don't really know what I did to solve this problem, and I still think maybe there might an issue but for now at least it runs. We'll see if it will start tomorrow, I need to put some good gas in it.

littlejt1

Please keep us updated. I am having a similar problem with mine at the moment. I had started some work on it and FPR is where I was heading towards...

turbo8

I had similar problems. here is what i did:
Replaced

fuel pump
fuel filter
dme\klr, fuel inject\knock\ temp sensors ,and ref sensors harnesses
dme relay
rebuilt fuel injectors
new speed and ref sensors
coil
spark plugs
spark plug wires
vacuum lines
inter cooler couplings
isv
knock sensor
temp sensor

thats off the top of my head

car works now

INURGRL951

Had the same problem on a not driven so much turbo I have but mine was the fuel pump seized up. Tell us how this turns out.

doug951

well for the 4th day in a row the car has started everytime. (maybe 15 starts)
The issue is now when i let my foot off the gas and let the RPM's fall to idle, the car just about stalls, the idle dropping to 500rpm for a second or two then shoots back up to where it belongs. This is new as this never happened before. The idle itself is very smooth and my vac reads 18-20hg when hot. So thinking I don't have a vacuum leak, what is causing this new stumble? I think it is still fuel related and that I haven't fixed all the problems yet. I should also mention that between 1/4 and 1/2 throttle the engine "misses", there is a slight stumble. But when I got WOT the car pulls hard and very smooth. This has happened over the last few years, nothing new.

So I don't really know why my car has continued to start but something happened when I tested fuel pressure, but I'm convinced these other two problems are related and that my no start condition might be back soon.

vanosman

idle stablizer
speed sensor behind manifold
replug the AFM sensor

remove the vac line from the AFPR, sets to default 2.7bar, too much fuel will make eng stumble and die.
leave the vac off during the next troubleshoot step.

DME crapped out on 951 sitting this winter. RPM was dead on startups which was the give away that brain was not shooting inj fuel, plugs were dry after cranking dead starts.

I bought an optima 34/78 redtop $170 for nothing . Just needed a $50 DME relay.
If relay is dead the RPM won't move, sounds like DME is not issue, it's the AFPR.

If you parked car outside in cold, pour some $5 HEAT water remover additive from O'reilly.
Try pull that vac from the front of Reg.

doug951

Tried some of the tricks you mention above, but nothing helped. It could be speed/ref sensor related, but when I checked the resistance they were fine. I feel as though the RPM's fall pretty quick when I push the clutch in and then it stumbles, but about 1 in every 10 times, it will return to idle normally and the RPM's seem to fall slower.

When the car returns to idle and stumbles, all of the gauges in the car bounce up and down, the battery one goes up to 16 volts. I did clean some grounds earlier this year. In fact this might be when the problem started. Could this be related?

Thanks for the help guys