94 e34 m50 in 85 325e... no spark

[JGood]

OK, I've triple checked everything, still no luck.

Engine cranks, I get fuel pressure, no spark. 12v at coil harness pin 15 in run. .8 ohms on the coil packs. 537 ohms on CPS. Main relay pin 87 has 12v in run.

c101 and c104 are wired (correctly... see my pin-outs in my other thread here.)


Any ideas?


Engine is 94 m50 from a 525i, car is an auto 85 325e that was five speed swapped a few years ago. Both were unmolested electrical-wise.

[416stroker]

Coil grounds?

[surebimmer]

Ground to body from the motor mount.

[gregslow318i]

are the cam and crank sensor reversed and do you have the right front crank pick up wheel

[JGood]

All ground wires are in place, and I ran extra grounds just as a precaution.

It's a vanos motor, no cam sensor (AKAIK).

Yes it's the right pickup wheel, I pulled the engine from the car myself and haven't removed a single part. It ran great before I pulled it.

[mattdk318i]

ECU........i had the same problem with my M50(94 525) I just knew the ECU was good because it ran in the other car!!! nope.... changed it and it started right up.

[88E30M50]

All ground wires are in place, and I ran extra grounds just as a precaution.

It's a vanos motor, no cam sensor (AKAIK).

Yes it's the right pickup wheel, I pulled the engine from the car myself and haven't removed a single part. It ran great before I pulled it.

I've been playing with Non-vanos M50s, so I may not know diddly squat about the vano engines, but I thought the vanos engines had a cam sensor. RealOEM lists a cam sensor for a vanos engine on this diagram: http://www.realoem.com/bmw/showparts.do?model=HD53&mospid=47404&btnr=11_1282& hg=11&fg=15

[FredK]

Yes, the Vanos engines do have a camshaft position sensor. However, if it wasn't touched, I'd leave that end of things alone. Sadly, I tried to troubleshoot a similar setup (1990 325is / E34 M50) for a local guy but I ran out of time. I never did find out how he got it started!

[Jean]

+1 , there is a sensor on the front of the engine.

[e30this]

Do you have the ECU bolted in the stock location??
Or do you have it just sitting there?

[JGood]

Yeah, nothing was ever unplugged or touched on the engine. It sat in one spot in the garage until I put it in the car. I don't think a sensor went bad.

I ran a 10g wire from a strut tower bolt and pinched it in the ecu case tab, and then set the whole thing on the strut tower bolts.

What ECU's can I try for my engine? I did seperate the case to see what chip was in it (turns out it has a Dinan chip), so who knows. I think it's a 402 or 403, definitly red label. What years/numbers can I try?

[Jean]

I am pretty sure you need a 413 for a vanos engine.

[e30this]

I did the same thing you did with the ecu and it still wasnt enough to make it run.
It either has to be bolted in the stock location or run sheet metal screws through the outer lip of the ECU and screw it into the battery tray.
If it ran fine before then the ECU isnt the problem. You have ground issues.
The ecu you need is a red lable 413. Also means no EWS...

[JGood]

Alright, I'll bolt her down tonight and see what happens.

Thanks for the advice guys.

[JGood]

That definitely wasn't the problem. First off, a ground strap attached to the casing, and setting the casing on the three strut studs and putting weight on it should be more then enough. But with just the strap, and a multimeter hooked to power on one lead and just brushing the other lead against the DME, I got 12v. So the DME is grounded fine.

I re-traced everything, again, and it all looks good. At this point I'm hoping for a bad DME/chip. Who's got a 413 laying around?

I have 5v at the coolant sensor, and ~2.4 ohms ~70 degrees.

Is there anything I'm missing that's specific to early model cars? I got the two c104 wires... is there anything else? There was two other plugs I disconnected from the engine harness right near there. I think one was purple.