Starting Problem

[Mike Brink]

I have a South African Manufactured 1992 BMW 530i V8. I have never had any starting problems before and the car is well maintained and runs smoothly.

It devloped a water pump leak. I bought a new water pump.

Before getting to work, I pulled the car out of the garage and parked it outside and drained the water. I left it outside overnight while clearing out the garage. Next morning there was a starting issue.

The engine cranked, started, ran for a second or two, then dies. I disconnected batteries, reconnected and nothing. I cranked the motor a number of times and the motor remains dead.

I thought it might be a water level sensor, so I filled up with water. No change.

Every now and then, the motor starts, runs for 2-3 seconds and dies. Then wont start again. I have checked spark, there is spark. There is fuel pressure.

After reading a few posts, It would appear as though it could be the crank / cam position sensor. I have been to the local guys for a bit of help but they want huge prices for workshop manuals and parts.

So, my request is as follows :

1. Any suggestions as to what I could do to narrow down the cause of the problem. I dont want to rush off and buy expensive parts to discover they are the wrong parts.

Is this an issue related to a water level sensor, or an issue related to cam / crank position sensor.

2. Not having ready access to a manual, just a simple description of where the cam / crank position sensors are on the engine, what they plug into and where and how I could unplug / test them without performing major surgery.

3. Any diagnostic tips etc.

4. Any where that I can download a workshop manual.

I am a technical person with a fully equipped workshop and many years experience in rebuilding motors and maintaining my own vehicles. I have oscilloscopes, meters and all the tools. Perhaps if I can unplug the relavant sensors, and look at signals / voltages / impulses and verfy that they are within desired ranges that would help.

I am assuming that the crank / cam position sensor sends an impulse. Is this generated magnetically / optically ? Does the sensor require a bias voltage or is is just a passive pickup with a little magent inside it?

Suggestions, advice would be greatly appreciated.

Thanks very much ... Mike Brink zs6meg