FLYT993

Got caught in traffic today for about 90 mins, temp gauge went slighty above 9 o'clock, but dropped back to normal once I started moving between 70-80mph. At the end of my trip I parked the car at a bank for about 10 mins, and when I tried to leave it wouldn't start. It cranked over, revved for about .5 sec. then cut out. It did this 3X. I let it sit for about 30 mins, during which tme I prayed, had a coke and a smile, and when I returned it fired right up. WTF? What's wrong with my baby? I'd appreciate any insight and suggestions from the brain trust in this community..TIA.

JChiles

DME relay maybe? You might want to try a search on it , could cause similar symptoms.

c4-toy

DME for sure, just happened to me. Last Sunday I stopped at a 7-eleven after which the car would not start. I had to have it flat-bedded to dealer, thankfully i was in Southhampton, NY and happen to be close to Storm Posrsche.
Tecnician said he did not find anything wrong when he tried starting it the next day; car started right up, no faults, nothing wrong. He cleaned and lubricated linkage while doing the troubleshooting.
While i was there i picked up a spare DME. Here is what i noticed. Since the car started right up with the old DME i left it in but i noticed the idle a bit on the low side; It even stalled on me once when i came to a complete stop at a traffic light when i engaged clutch. Everytime i would come to complete stop the RPM's would almost go to zero. I replaced the DME when i got home with the new one and i notice big difference in the RPM's, much smoother now, and does not seem to go to zero when i come to a stop with clutch engaged.
Morale of the story, it's worth the $40 to spend on a new DME. -Joe

Bruce SEA 993

Joe

Did the Dealer tech disconnect the battery? Your symptoms sound exactly like the cycle the computer goes through when the power has been disconnected from the ECU as when you change batteries or in your case when a tech was diagnosing. Just curious. I haven't heard of the DME causing that problem...but then that is why these posts are valuable!

Ciao

revolution993

are you sure the stalling problem is not because of the ISV???
i had the same problem...

FLYT993

Thanks for the input. One can always count on the expertise and knowledge of this board to narrow the focus or pinpoint the gremlin. This IS a great place!!

geolab

when car is hot and takes some time to restart, a good reason for this is the Fuel Pressure regulator.
A small pressure regulator found on the fuel injection rail right above the Cylinder #3 on the left side of the engine. Half an hour max. to change.

c4-toy

Bruce, yes i believe the battery was disconnected because when i picked up the car the radio presets where gone. My ISV was cleaned about 2-3 years ago. I dont know what to make of it, all i can say is i notice a difference with the new DME, for sure the car is not dying out on me anymore as it was before. One other point, i was talking to another Porsche tech and he mentioned that a small vacuum leak would also cause this stall behavior. There is a way to detect these with some special "smoke machine" whatever that is. -Joe

Kika

Could be the starter going bad, I had similar symptoms on my SC. Whe it was hot, the starter would stick, I am not sure, but I think due to slight expansion , the part that gives the motot the initial kick, would not come out. I could reach under the car and hit it with a hammer to loosen it, then it would start. Easier option was to push start it, i got really good at it. Ultimately I had to replace the starter.

JasonAndreas

Hot start problems encountered by the 964 and 993 are almost always a result of failing solder joints in the DME relay. When the problem is happening on a regular basis you jumper the DME relay with a few paper clips or some wire to diagnose it.

Garth S

Jason,
Do you recall the relay pin numbers that are to be bridged on the CE board? If it is similar to the 928's, a 3-way jumper with standard male spades is the 'tester'. TIA

coltj

Garth,

Is this the info you're looking for? From one of Jason's posting in this thread;


https://rennlist.com/forums/showthre...light=DME+part

"If you suspect the DME relay and you don't have a replacement you can jumper a wire across connectors 3 and 7 in the relay socket in the fusebox (pins 30 and 87b on the relay). If the engine starts okay than you know you have a bad relay. And if you're ever stuck somewhere you could attach another wire to connector 8 and actually drive a short distance. You can drive with only two wires but the DME will set itself to limp mode because there is no power running to the O2 sensors"

Garth S

That's it Thanks.