herrtzeber

ya well maybe you read my earlier post a few weeks ago about problems that i ran into while swapping chips on my 88 951. brand new chips are installed currently and in their sockets properly. engine turns, engine no start. where do i go from here? fuses to check? anything i couldve fried that i could check? with something like this, i just have no clue what to do. autohaus told me they cant really help me much unless i want a new ecu... but i dont. do i?

89951DREAMER

First check the basics. An engine needs fuel, air, compression and spark all timed properly to run. Have you checked these? If you have spark, make sure your injectors are firing. Make sure you have adequte fuel pressure. Is the timing belt broken? If so, you will have spark at the coil, but not distributed to each plug properly. Do you have compression? If you have compression, spark and spark distribution, good fuel pressure, and no air restrictions and it still won't run, check for power at the ECU. You may have a bad DME relay. Don't assume that the computer is fried until you have checked everything else. If the injectors are firing while cranking, your DME relay is OK. Hope this helps.

quinnfiske

Porsche publishes a test plan for these Motronic systems. I believe the number is WKD 453 920 although I have seen other numbers. They take you through all the sensors and stuff. If the problem originated with the new chips, I would put the originals back in and try it then

hosrom_951

The manual also has DME test proceedures and also covers the sensors (how to diagnose), voltage readings and general faults on what to check........

PM me if you like a picture of those sections.......

mochman

check for fuel injector pulse the ecm runs this, the klr runs the boost sector including the timing, I had no spark once traced it back to the KLR

herrtzeber

another member pmed me a copy of that manual so hopefully i'll be able to determine someting with that. thanks alot. guess otherwise the next thing to do is check spark and see if my injectors are firing. way i see it, its one or the other or both that isnt working but even when i determine that, i'm not to confident about fixing that dme.

quinnfiske

I had a DME failure. The timing would retard until the engine quit. I found a place called Systems Consulting. The guy has all the schematics and stuff. Really knowlegable about troubleshooting. He fixed it for something like $250. He first had me jumper out the KLR to isolate the problem to the DME. I provided a link below.

http://www.systemsc.com/

LHC

Hi herrtzeber,
I would appreciate if you would kindly
pm me a copy of the manual as well.


Thank You.