1999 986 2.5 with empty DME, help needed!

[landrovered]

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]

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]

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]

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]

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.