'92 e36 325i won't start

raftel · 01-10-2004, 04:07 PM

My '92 e36 325i sedan will not start (214K miles). Cranks well, drove it this afternoon without issue. Won't start this evening. Did the same thing last fall, let it sit for a week, actually called a tow truck out when I decided to try one more time - and it started then. Took it to my favorite independant shop anyway, where they found a code for lean mixture. They checked extensively for fuel delivery problems, took extensive test drives, but no other problems. Changed the O2 sensor with a Bosch unit.

Now the car is doing the exact same thing again. What could cause this intermittent no start condition?

Thanks!

raftel · 01-11-2004, 04:22 PM

Started diagnostics - I find that the main relay for the DME is only showing voltage at pin 30 with the ignition off. According to the Bentley manual, I should be seeing voltage at pin 86 or 85. How do I get behind the relay to investigate the repair the connection.
I am referencing section 130-7 of the Bentley manual.

Also, the plastic tangs that retain the relay snapped off - can the socket be replaced, or is this even needed to ensure the relay stays put?

marcdg · 01-25-2004, 06:15 PM

Had same problem with my 92 325is. Turned out it was the crankshaft positioning sensor which is located just below the thermostat housing. The lead runs under the intake manifold. If you take the lead off and ohm it, I think it is suppose to read 1280. I had no reading, replaced it and it started right up. If your fuel pump is not pumping and there is no spark then it is very posible that it is the crankshaft positioning sensor.

Good luck!

Marc

raftel · 01-26-2004, 05:29 AM

Thanks for your response - I think I have it fixed. I replaced the crank sensor a couple of years ago - years of coolant leaking onto it finally did it in. But I had also gotten an error code for it that time.

Also, as far as my previous post on the relay, it turns out that the position of the fuel pump and main relays in my car are reversed compared to every shop manual I've seen on the car. Once I started testing the right relay, everything checked out fine.

Here's how I fixed it - since the relays were good, next to check was the pump. I bypassed the fuel pump with a fused jumper as indicated in the Bentley manual, and the pump fired right up. I replaced the relay, but the problem returned in two days.

This time, I removed the rear seat cushion and fuel pump cover. With my left hand turning the ignition key, I used a hammer in my right hand to 'encourage' the fuel pump to activate. After a couple of taps, the car started fine.

Replacement of the fuel pump took less than an hour. I think it is fixed now :-)