Hello everyone.....

OK, so here's the problemo..... Turn one at Willow Springs, a fast left hander.....car stumbles on corner exit. Feels like fuel starvation, but had enough gas and turning the other way.... it fights to run a few more hundred yards a dies. I crank and crank and finally it starts for a few brief (and final) seconds.

After being towed in, the fantastic SoCal crew comes to the rescue. We throw a new DME relay in (for a quick let's see) and nothin'..... Check the tach, no bounce.... (?) check the fuel pump, and nothing. I observe that the reference sensor (or speed? top one...) plug is in sad shape and maybe shorted against bracket. Check fuel pump power, and gets 8.5 V.....fuel pumps are pretty basic machines..... power? yes! It should work work if it has power. Diagnosis complete.... get 'er home and fix it.....

New fuel pump in.....AND......nothin'

So... recheck sensor plug.....it had a crappy previous repair (not mine...swear...). Obviously I need a new one, but patch it for now. Crank it, and behold.....tach bounce. Check spark..... no spark..... check fuel pump....nope.... jump past the relay (30&87), nope.....still nothing. Check voltage at pump.....at no point did I ever get a reading....

Is it possible the reference sensor wire (#78 I think) shorted and ate the DME? Did the short eat the sensor? Anyone wrestle with this before.....c'mon, I know you did...

Thanks for your attention!

Cold solder joints in the DME. Pull apart and inspect closely on the large pins with heat sinks near them. These develop cold solder joints (loose solder around the pin) which need to be re-done.

I ALWAYS add a heat sink to the case and have put on 12V fans too to help. They get very hot and with the added vibration do this. Turbo cars are worse with the added heat from the cross over pipe right in front of the passenger floor. I used to move the DME back away from the firewall too.

Hello again everyone-

I wish I could say I have it solved, but have made progress, and now I think I may have figured it out.

Thanks Joe for your thoughts, while this does not seem to be the issue this time, it does compel me to modify how I have the DME mounted to avoid that kind of failure in the future.

Thank you Tim! Ok, everyone here, you know which Tim. If you don't....CRE in San Diego...look him up.... you must know Tim if you have a 944. I was told this when I first started with 944s, and frankly did not believe the stories of his tireless efforts to keep us and these cars on the road. Er, track, or both, really.....all true! I need to check in with you though, and will call you tomorrow.

Ok, so it seems my symptoms may have been disguised by wiring issues that created some intermittent (and false) symptoms. With those solve, I have good current in all the right places, and everything cranks, pumps fuel, and gives spark. It have fired up twice since I got it home (not easily!) Just now it started but ran as rough as I have every experienced it. Super rough and seemed to search for idle (maybe just struggling to run). Since I had fuel and spark, I thought (maybe finally!?) to check timing....cam gear groove to pointer? check. Observation hole on the top of the bell housing, where is it? Holy crap! Where'd my pointer go? Fresh metal break and no more rubber pointer! What the heck?

Oh, and no "OT" either, but rather a "10"...... so here's my question: Is it possible to have the timing belt jump a few teeth without grenade-ing the whole motor? Is it possible to have the timing that far out and still run?

Where'd my pointer go?

I'll pull the timing cover tomorrow and check belt alignment for sure, but tell me your stories!
Thanks

So many possibilities, but there is spark and fuel. All you need after that is air and compression. Based on this, maybe do a compression test? That would tell you if you if you have serious problems.

Are you sure the injectors are firing? I've recently had perfect pressure at the fuel rail but the injectors werent doing a thing. (clogged) I'm not sure how much clearance there is to be had with skipped timing but I have have seen the effects of missed shifts. The pistons and valves would prefer to not be in the same place at the same time. From my understanding you will know about it if it happened, did the car make noises as it was dying initially?

Yes the belt can jump a few or be put on wrong and run like crap. You will have bent some valves too if that happened. Compression test or leak down after you recheck timing.
Sorry to hear of your woes clay. Keep it up. It's worth the effort.
See ya on track.