'92 318is won't start

[swordfish]

I just bought the car. I decided to replace the brake rotors and the rims. So far so good. The airbag needed replacing so I disconnected the battery for a while, approx. 5 days, but did not remove the airbag. In between that time, the climate changed from hot to colder weather and it also rained for two days straight. I reconnected the battery and attempted to start. Nothing. I let it sit for a day and tried again, same problem. After trying and trying, it finally started very rough, and then died after a few seconds. I can't get it to start again. I checked all the fuses and they are ok. The relays are also fine, although the one controlling the fuel pump gives brief contact when ignition is on, then comes back to neutral position; I don't know if this is normal. I attempted to keep the relay in the on position (to keep the fuel pump turning) but still nothing.Using a timing light, I checked to see if there was a spark, but the light would not flash, so there is no ignition it seems. What could have caused this problem? The only thing that changed are the rotors/rims and the weather, that's it..

[swordfish]

Well I have solved my own problem. It seems water somehow managed to get into the DME. That's what was causing the failure. I dismantled the unit and let it dry for a bit before putting it back together. Problem solved!

[Wayne 962]

This appears to be a common problem with these cars - good thing you didn't fry your DME unit (also a common problem)...

-Wayne

[Jared at Pelican Parts]

If I can also offer some advice regarding DME's, If in the event that you need to jumpstart your car, disconnect the battery. If you jumpstart it with the battery connected, you will most likely fry the DME. Learned this one the hard way...

[Kiwi Andy]

I'm new here and, well, whats a DME?

[swordfish]

The DME (I forgot what it stands for) is the main computer. It is what controls the fuel system, ignition, and so on.

[Dave at Pelican Parts]

"Digital Motor Electrics" (or Electronics or something very similar). It's the engine management system--more or less, a fuel injection system which also controls the spark (ignition).

--DD

[WMostellar]

Could a moist DME cause the electrical system to only operate in the accessories position of the ignition.

If the key is advanced to run, it only receives electrical power for < 1 sec.

William
WMostellar@GMail.Com