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99 Z3 won't start! Help!

3605 Views 3 Replies 3 Participants Last post by  dghahn
1999 BMW Z3 coupe with 2.8L (M52 motor) with Siemans 42.1 DME

Ok, I got the car cheap b/c no one could fix it. I'm pretty sure that the car was jumped off with the battery cables backward and reaped havoc. It burned ground wire in half. Fried the computer, Fuel pump, and a relay, all been fixed/replaced. New DME installed and set up by BMW of montgomery. Here is a list of what I've checked and then the problem I'm stuck at without knowledge or prints of the actual DME. The engine will turn over but won't bust off. No fuel through injectors, no fire from plugs, no SEL.

Good PSI on fuel rail
Good compression
Checked hot and ground to DME.
Diagnostics scan shows no faults.
Crank position sensor reads good out of car. - analog meter not fluctuating, holding at 6v on signal going into DME. Tried 3 different sensors, all good on bench. Reads 12v on signal with sensor off and 0 with sensor on. (NC)
Camshaft position sensor reads good IN the car. - checked signal with analog meter. Have fluctuation.

Ok, I checked the voltage on the pins of the plug from hot to ground where it plugs into the crank sensor to make sure I didn't have a short or somthing, haven't checked continuity of signal yet. It's my understanding that the only thing the car uses to start is those 2 sensor and I understand it gets a ground from the DME to fire injectors and coils. These are holding at 6v as well. My next plan is to cut the signal coming from the crank sensor and isolate b/w the sensor and DME. I have amp clamp, DMM (both Fluke), O-scope, and 12V pwr supply. If I had prints of the DME I can read and do the math on it all but would rather not if I can help it. Do you have any idea why or what would hold it at 6v?
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Have the DME and EWS system been synchronized?
Yes, supposedly the bmw dealership did it when they put in the new DME. I would think that if they wouldn't the EWS wouldn't let the immobilizer enable the starter. I've found that with x60004 cable unplugged my 6V goes away on the injectors and coils. I know it's not the power or ground in 60004 causing it cause the clutch and brake circuit work which is on 04. However on pin 21 I believe is the o/p for the oil level and I have 0V. It leaves the oil level, goes to the immobilizer and back to dme as a coded signal. Can anyone verify that it's supposed to be a 0 or 12 V output for the oil level circuit. If anyone has a 99 z3 or e36 with the 2.8L engine could they verify pin 21 on 60004? With just key on and then actual start of engine.
Did you resolve your problem?

Did you ever find a solution to your problem?

I have the exact same issue with a 99 z3, and I have tried pretty much the same items as you did.
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