1999 986 2.5 with empty DME, help needed! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

frank914-boxster · 05-23-2010, 10:50 AM

I have a 1999 2.5 boxster and it has given me lots of fun driving. But not anymore... Two weeks ago I tried to start it and nothing happened. the dash lights came on but the starter motor refused to turn over. Also I couldn't hear the start relay click. My initial thougt was that the key was no longer recognized by the car. I towed it to the dealer. He suspected the ingnition. (It was rather worn) and replaced it to no avail. Then he hooked up the computer. the key was recognized by the car. When cheking the DME we found that it was completely empty! All data that should have been stored was reset to 0! Even the VIN and motor number were gone! We reprogrammed the VIN and motor number into the DME but still no starter motor. We checked the clutch switch (it is a USA model) and even bypassed it. Still nothing. It drives me crazy, finally we are getting some sunshine and the car sits in the shop not running.

Does anyone recognizes this, what caused it, how to solve it?

Any help is much appreciated!!!

Frank

KevinH1990 · 05-23-2010, 12:19 PM

Are you sure it isn't the battery? I understand that the dash lights lit and the starter relay didn't click, but the battery is worth a check.

The engine number isn't in the DME memory of most cars from what I understand.

Lil bastard · 05-23-2010, 08:39 PM

Ignition switch

Cheers!

frank914-boxster · 05-24-2010, 12:26 AM

Thanks for the input guys, but both items have been checked and are perfect. The ignition switch has been replaced for a brand new one and the battery was tested and is in perfect condition.
What I forgot to mention is that we tried to start it by towing it. In this we by-pass the starter, but it still wouldn't run. So I am 100% sure it isn't either of these things since it would have started then when we towed it. The DME cuts out the ignition and injection.

Any other ideas?

landrovered · 05-24-2010, 04:51 AM

I can't imagine that the dealership would not check the integrity of the battery as part of the diagnosis of the DME, especially after finding the data on it had been wiped out.

I would be inclined to think that the DME needs to be replaced. It may have been subject to some sort of static discharge which wiped the memory or the board failed catastrophically for what ever reason. THe DME controls almost every circuit on the car. I would not attempt to troubleshoot the problem until you have tried a "known to be good" DME in the car.

Has you car been in any thunderstorms lately?

frank914-boxster · 05-24-2010, 05:06 AM

No, it hasn't been in a thunderstorm. This just happened for no apparent reason. Tommorow we are going to try to replace the DME (and ignition key) with a unit from another boxster to see if that works.

Frank

Trey T · 05-24-2010, 06:38 AM

Typical starting system w/ MT has the clutch switch and starter relay. Immobilizer/DME is independent from the starting system, from what I have seen.

I never worked on porsche but when you have problem like this, I find it best to work backward and test the starter wire and work your way back to the starter relay and back to your ignition switch. It's a pretty simple diagnostic job, IMO. Or the other way around.

seningen · 05-24-2010, 06:56 AM

Quote:

Originally Posted by Trey T

Typical starting system w/ MT has the clutch switch and starter relay. Immobilizer/DME is independent from the starting system, from what I have seen.

I never worked on porsche but when you have problem like this, I find it best to work backward and test the starter wire and work your way back to the starter relay and back to your ignition switch. It's a pretty simple diagnostic job, IMO. Or the other way around.

If your battery is too weak to start the car you will
see the instrument cluster and/or the HVAC
dim and release while you are trying to start the car.

One of those you have to see it to understand completely
but it is obvious.

Sometimes if the battery is really low -- turning the HVAC fan on high
will get this same result -- or you will find you can't put it at max
it caps itself out.

you can also put a meter on the battery and watch the voltage drop
substantially.

M

frank914-boxster · 05-24-2010, 07:08 AM

again, the battery can not be the problem. I can open and close the top on battery power with no problems whatsoever. Als checking back from the starter motor, wiring to the ignition wouldn't help, we can not start it by towing, the starter motor is not used then at all. There simply is no ignition spark and no fuel injected.