93 E36 DME and ground magic - United Bimmer Community

**panorama** · 11-17-2006, 02:48 PM

My 92 325is couldn't be started and the mechanic told me that camshaft and crankshaft position sensors were bad. Then the fuel pump was bad and had to be replaced too.

This apparently still didn't fix the problem because he told me that the computer didn't have ground on the DME relay so he ran a wire from ground (body) to the relay which basically makes the car think that ignition is on.

He says that it's the computer that's busted and I need to replace it.

Does that make sense? I don't know what to do at this point. The car runs but I have to disconnect that ground or the battery dies. This is wonky!

I took the DME out and will look for replacement but I just wanted to hear your opinion on this.

The DME on this car is 0 261 200 413

Thank you for your help

**215BIMMER535** · 11-18-2006, 03:21 PM

assuming you mean it works perfectly if you use that ground wire and then disconnect it when the engine is off, you could splice that ground into another one that is disconnected when the ignition is off, that would be cheap and you wouldnt be poppin the hood all the time! just an idea

**panorama** · 11-19-2006, 04:44 PM

That's a good idea but is it ok to hook it up to any ground that's activated by ignition? Aren't the relays supposed to shield one electrical circuit from another?

BTW I tried other relays and they did not make a difference. Does that mean that the DME is bad for sure? It's a strange thing because the car works perfectly with that ground connected so the timings are fine and obviously the spark and injectors work properly.

It's just weird...

**panorama** · 12-03-2006, 03:04 PM

I got a refurbished DME off eBay and replaced it today but that didn't fix the problem.

This is weird stuff. Maybe the relay itself is bad but the mechanic said he tried replacing it with another one and it didn't fix the problem.

When that ground cable is unplugged the car just cranks and doesn't start but as soon as I connect it, it starts without a problem.

**lasmariaspr** · 12-02-2010, 03:07 PM

I have the same problem, did you find a solution to this not starting without dme ground wire connected?

**Manolito** · 12-02-2010, 09:26 PM

I have a really bad feeling about this thread. Someone needs to look at the wiring diagram and figure out exactly what it is that you are grounding. My fear is that you are defeating the safety feature that won't let the fuel pump run after an accident. I am not familiar with this particular application, but the way the Europeans normally do this is to have the DME supply the ground to the fuel pump relay, which it does only when it is getting an ignition pulse. This keeps the car from pumping fuel out on the ground after an accident when the engine is off but the key is still on. I don't know where you are connecting this ground, but I don't like the sound of it.

**lasmariaspr** · 12-03-2010, 01:58 PM

Well since it wasn't the DME maybe it would be wise to try to trace wire 85 on DME to ECU pin connector for continuity with a voltmeter, I will try this and let you know.

**Manolito** · 12-03-2010, 10:56 PM

Good! We don't want to loose any Bimmer Brethren!

**lasmariaspr** · 12-04-2010, 09:13 PM

Well today I tested crank sensor and it was good. Tested for continuity of wires 85 ground of both fuel pump and dme relays to ecu pin connector and were good. Still have to test ignition wire which I read feeds the ecu dme. But also, car starts with ground wire connected to dme socket pin 85.

**lasmariaspr** · 12-08-2010, 06:21 PM

Finally figured it out, Pin 27 of the DME is not sending a ground signal to DME wire 85. Can't swap another DME because system is EWS II, and would have to be programmed. Now what?

Big Evil · 12-09-2010, 11:49 PM

take it and get it programed, otherwise it won't be fixed

**lasmariaspr** · 12-10-2010, 01:25 PM

Just one missing ground on DME needs programming ?, car is running fine so far.

Big Evil · 12-10-2010, 03:11 PM

"Finally figured it out, Pin 27 of the DME is not sending a ground signal to DME wire 85. Can't swap another DME because system is EWS II, and would have to be programmed. Now what?"

DME is not sending out a ground signal (presumably a bad DME is what you're saying here). You want to replace the DME? There you go.