Hello all. First post here. I'm a US national living in Germany. I have a 1986 Euro 635csi (no CAT). Car ran like a dream when I first got it. Then it was running rough like it was going on 3 cylinders. Then no start. Fuel pump works. There is no power getting to the coil. I have been able to use a Multitester on a continuity setting to confirm the wiring is good and intact for the - all the way to the ECU, and for the + all the way through the fuse box to the ignition switch. The ignition switch also checks good. Wiring from the main relay to the ECU plug is good. At this point I suspect that possibly something in the antitheft unit has failed and cut power to the coil. Don't know where that unit is, but suspect it's deep in the dash. Any suggestions would be welcome at this point. I have halve of the wiring diagrams.....and they are all in german. If anyone has them in English, that would help. What I have doesn't seem to cover anything through the ECU or other control units.

Regards, John

General 635 wiring diagrams here:
BMW 635 ETM (http://65.109.90.124/www/bmw/library/etm002.htm)

Or download your model year here:
BMW Manuals (http://wedophones.com/BMWManualsLead.htm)

Any chance that water might have got into the ECU? If the windsheild seal starts to fail on the passenger side, then water will fall right on to the ECU mounted above the glove box and cause intermittant and/or fatal electrical issues.

Joe M in WV

General 635 wiring diagrams here:
BMW 635 ETM

Or download your model year here:
BMW Manual

Any chance that water might have got into the ECU? If the windsheild seal starts to fail on the passenger side, then water will fall right on to the ECU mounted above the glove box and cause intermittant and/or fatal electrical issues.

Joe M in WV

Thanks for the reply. Forgot to say the ECU was tested OK in another 86 635. So I'm going with it being OK. How does the anti theft system disable the car....Kill power to Coil?

Try Rick's No Start Shark Page (http://home.bellsouth.net/p/s/community.dll?ep=16&groupid=160912&ck=) for some troubleshooting help

Good luck with it!

Try Rick's No Start Shark Page (http://home.bellsouth.net/p/s/community.dll?ep=16&groupid=160912&ck=) for some troubleshooting help

Good luck with it!

Thanks. There is a section of that page which talks about a no start problem related to the OBC. That was something I suspected and the first thing I will pursue next.

List of things checked.

ECU tests good in another 635.
Main relay Jumed, No start. Main relay is new.
Green wire from Main Relay to ECU tests good for continuity.
Green wire from ECU to OBC tests good for continuity.
Jumped the two green OBC wires, still no start.
Ground wire from Ignition Coil to ECU test good for continuity.
Positive wire from Ignition coil through fuse box to igition switch tests good for continuity.
Ignition switch tests good.
With ignition switch on, there is still no power to the Ignition coil.....No start.
Fuel pump works, fuel gets to engine...there is now gas in the oil I've tried to start it so many times. Compression test at 13 bar for all cylinders.


:(

Dynamite......blow the thing up I think is the best option now. :D

good it be the pulse generator?

i read also there is a fuse in the obc [site off bmw big coupe]

i read also there is a fuse in the obc [site off bmw big coupe]

Pulse generator?

OBC was bypassed. Going to looh at engine position sensors next....but will they cut power to the coil?

List of things checked.

ECU tests good in another 635.
Main relay Jumed, No start. Main relay is new.
Green wire from Main Relay to ECU tests good for continuity.
Green wire from ECU to OBC tests good for continuity.
Jumped the two green OBC wires, still no start.
Ground wire from Ignition Coil to ECU test good for continuity.
Positive wire from Ignition coil through fuse box to igition switch tests good for continuity.
Ignition switch tests good.
With ignition switch on, there is still no power to the Ignition coil.....No start.
Fuel pump works, fuel gets to engine...there is now gas in the oil I've tried to start it so many times. Compression test at 13 bar for all cylinders.


:(

Dynamite......blow the thing up I think is the best option now. :D

Well damn...

...look at it this way, you'll have an update for the No Start page!

I apologize for continuing to mention Roadfly, but I think more wrenches hang out there. You might want to lay out the problem you're having and what you've done so far there...

I'll float it by Roadfly also. Thanks!

sounds like the pick-up coil ("pulse generator")

sounds like the pick-up coil ("pulse generator")

You mean one of the two sensors in the bell housing which connect to the wiring harness at the brace on top of the engine? That is what I suspect, but I don't know a good way to test other than replacing with a known good sensor.