Freeway cruising cut-out

[Bambi]

I have a 1993 URS4. i'm running a kkk26/27 and 3bar map sensor. I hav just rebuilt the engine with spm rods, new bearings, rings etc and have now covered approx 800km. In town thew cars is fine, but now and then (even before the rebuild but after the turbo upgrade) the car would cut out on me cruising along on the freeway. I has never done it in town. She\ll cut out, the fuel pump relay goes nuts clicking away for about 10 seconds and then after about 20 seconds after I switch off she\ll start right up again - no problem. Last night however she cut out 15 times in 40kms. I stopped at afriends for 3 hrs, an going home on the freeway no problems. I pulled the fault codes and are as follows:

65535 - ECU control module memory error (or something to that effect)
N75 open circuit (I know - I' still running in on low(no) boost)
XXX cant remember - but description was fuel mixture lean or too rich
Adaption limit not reached

I'm thinking

* maybe fuel pump relay on the way out and dropping fuel pump causing fuel mixture message

* maybe check sum error on the chip causing memmore error thing - causing cutout of engine

* Maybe ecu "op die koffie" - Afrikaans for not so good nomore

Can anyone help?

[UrS4boy]

The J17 fuel pump relay is controlled by the ECU, i.e. it is kept engaged only if the ECU has a signal from the cam position sensor (hall sender) during start up and then, once the car is running, a signal from the crank position sensor. If either of those two senders were flakey (intermittent) then the ECU would probably have an issue keeping the J17 engaged. However, AFAIK, both those senders would throw a CEL (MIL) light. The blink code for the Cam sensor is 2113. So if you don't have a CEL, then I have to guess that your J17 has a problem. Its not very expensive so I suggest you get a new fuel pump relay, install it and see what happens. If its not the J17, then look to the cam and crank sender wiring and, perhaps, the senders themselves. If that's not it, then you need to try another ECU.

J17 info:

http://forums.audiworld.com/s4s6/msgs/149827.phtml

Cam position sender info:

http://forums.audiworld.com/s4s6/msgs/101711.phtml

Crank position sender info:

http://forums.audiworld.com/s4s6/msgs/116988.phtml

Good luck.

Dave F.

[Bambi]

thanx ! I'll start with the J17