No crank, no start, no spark- 1985 735i

[my1ste23]

BRAND SPANKING NEW to me FIXER UPPER

1985 735i

The story...

Scooped the car up last week. The previous owner kept telling me it wouldn't start and he hadn't tried to start it when it quit. It started for me when checking it out. Ended up buying it just from hearing it run. It's a fixer upper and I did drive it around the block when delivered. Unfortunately, right after parking it, it would only crank but wouldn't actually start.

I'm just thinking outloud.

Tested the primary and secondary coil resistance was a bit low but not by much. Contemplating swapping it out anyway as it looks original.

Also flirting with the idea of cam and crank sensors flopping out.

How would I test those?

Am I on the right track?

Haven't tested fuel pump yet. How would I test that?

Thanks in advance as I know more heads are better than one.

[8991XJ]

Sensors are tested based on the method detailed in the Bentley 5-Series 82-88 repair manual. Probably find details on mye28.com.


More possible resources: BMW E23 7-series information and links (e38.org) sure some dead links but what is there is good info. Check out the Electrical section for the electricaltroubleshootingmanual for your car the ETM.

[Feyrerm]

When I tested the fuel pump I just picked up a cheap guage at harbor frieght and put it in the fuel hose by the firewall. Then I could rest the guage on the winshield and see the preasure constantly.

I'm not sure if the 735 uses the sensors on the transmission like the 733 for timing, but if it does you def want to KNOW they are broke before you tackle that job. They are a nightmare to get out and even worse to get back in. They esentually corrode right to the block.

The coil seems like the best place to start though if you already tested it and its out of spec. this would probably explain why it starts intermitently.