I am posting this in case anyone else has a similar issue. Recently my 96 C4S was experiencing a problem much like vapor lock. After driving the car and then parking for a few minutes, it would not re-start. It would just crank and not fire. Then after sitting for a few more minutes, it would fire right up. I feared that I had the dreaded wiring harness problem or some other difficult to diagnose electrical problem. Not to worry, after a short discussion with Steve Wiemer, he felt it was a DME relay causing the problem. So up to the Dealer this morning to purchase and swap out the DME relay. Sure enough that was the gremlin, only a $20 fix. Thank you Steve!!!!

Doug

D & M Racing

 

Hi Doug:

Happy to help, anytime

IMHO, anyone with a Motronic-equipped car should always carry a spare DME relay.

If this might save somebody from making a long walk, especially at night or in inclement weather, its worth the trouble,....

 

Steve,

Refresh me which cars have the Motronic DME? Thanks.

Brian

 

Hi Brian:

All 911's from 1984 to the present use versions of the Bosch Motronic and they all have the relay that controls the DME (ECU) and the fuel pump.

Its a common failure item.

 

Steve, can you tell us the part number for the 993 models? And, where is the relocated in the car? Thanks.

 

Dick, Both these numbers appeared on the relay box 993.615.227.00 and /0100226, not sure which is the P/N, nor whether this is the same part for all 993s. The relay is located in the front right fuse box (in the trunk).

Doug

 

A while back, I had the problem of my car turning over, but not firing. After much research, I spoke to my hometown dealer and he said that whenever a car comes in with anything remotely like that, they replace the DME relay. He said that many 993's have the old relay with a part # beginning with a 944. prefix. He said that porsche has put out a bulletin stating they are defective, and should be replaced with the 993. prefix relay. I ordered one (#993.615.227.00). I planned to wait for my problem to come up again, plug in the new relay, and see if that indeed is the cause. The car has been running fine, so I haven't been able to test it yet. I'll be sure and post the result's. Like steve says, it couldn't hurt to keep an extra at $20, or atleast upgrade to the right one if your car has the 944 prefix.

I'd like to thank Steve Weiner for all his help and time in sorting this problem, and some others I've had. He's a great asset to our 993 community, and I'm glad he's here!

David

 

Yes, I looked at my old relay and it had the 944 prefix.

 

Does the same issue appear for 993 TT cars? I checked and my DME relay part number is the older 944 prefix one.

Thanks..

Jeff

 

Hi Jeff:

According to my sources, the DME relay has a part # of 993.615.227.00.

There might be newer version but the only difference in the part # would be the last 2 digits to indicate its newer.

Carry a spare, Sir.