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BuzzBomb

Earlier e24 wiring diagrams?

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Im in a bad way, friends.
A rebuilt engine from a 1983 635csi, and I'm using the original harness. I verified that the ECU is good in another car. The install is in an '85 e28 528i. Everything hooked up, I get the engine to turn, but no spark and no fuel pump. I confirmed that the green lead from the fuse box has continuity at the coil. I confirmed that the fuel pump runs when directly connected to a battery. The main relay clicks at key on, and I get 12V at fuse 1 while cranking. But, I only get 5 or 6V at the coil while cranking. That seems strange. 
Anyway, I need help by someone who might have some insight. Using this harness in an e28 shouldn't make a difference...should it?
Does anyone have or can steer me to wiring diagrams for an '83 Euro 635 so I can at least verify that the harness is good?

(Copied from another request I made in another forum.

Edited by BuzzBomb

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E24/28 is the same chassis so shouldn't be an issue

Presume you've used the motronic loom wholesale? Should work ok.

Your point re coil is interesting I've just had to resurrect an mg midget that hasn't been started in 20 years. The manual there suggested that 6v was the normal running voltage reduced by a ballast resistor and by passed on cranking. We was 9v on cranking.

We figured the starter was taking too much juice so we added 12v direct to the coil +ve. A few coughs and splutters and we got it running.

Might be similar here?

In terms of diagnosing motronic I found the Haynes 520/525e manual was good, Bentley and the Haynes engine management manual.

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On June 14, 2016 at 3:44 PM, duncan-uk said:

Just to clarify. Original harness? From engine or 528?

Sent from my iPhone using Tapatalk

It's the harness that is correct for the engine. The e28 has the ignition amplifier on the inner well up by the headlamp. That is all that's left of the 528 engine management. This harness didn't use one of those.

Good thing is, after pulling things apart on the harness today and checking sensors, etc, I tried one more time ant it fired right up. Something wasn't happy and needed to be messed with, I guess. 

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