Another random no start. CPS?

[edoc]

Hey everyone, need some help. 91 318i won't start after sitting for a couple months. I replaced the fuel pump because I couldn't hear it priming, still nothing. Replaced fuel pump relay, nothing. Cranks but won't start. I put power directly to the fuel pump to get it to run and have tried starter fluid but it won't start. I put one of those screw driver looking lights with the ground clamp to where the fuel pump relay goes and couldn't get it to light up. I've read similar posts that point to the crank position sensor. What do you guys think? I know my way around a car well enough but I'm not good with electrical, so try to dumb it down if possible. Thanks

[IRON-E]

What about the coils, are they still good?

[jlevie]

The pump doesn't prime when the key is turned to start. It is controlled by the DME and only runs when the DME sees timing data from a rotating engine. In this case I'd suspect that the DME isn't powering up (bad fusible link, bad, main relay, of no START signal) or isn't getting timing data from the engine (bad CPS). But then you could have a dead DME.

[Bizzyboy904]

I'm sort of having the same problem. Try to jump the fuel pump relay with a paper clip or wire. It should be the jumped front to back not side to side. And turn the key to the on position. Here you can check to see if the fuel pump is running. If it is the next step is to check the CP's sensor. There is a little black box under the intake, and it has two black connectors coming out of the front of it. The one on the bottom is the crank position sensor. Pull the connector and check the resistance on pins 1&2 it should be about 640 ohms. Pins 2 &3 should read about 3k. Only check the actual sensor do not check the plug that leads to the DME. I recommend buying the sensor from BMW not aftermarket because well just trust me on that one... Anyway you can run the car with just the jumped relay terminal but I wouldn't really recommended it for long.

[edoc]

Thanks for the replies. I tried bypassing the DME relay with paper clips from 30 to both 87s. No luck, still won't start. Does the test I perform eliminate a bad DME relay? I read that "if the car starts while DME is bridged, this confirms power to 30 and 87s are working. It doesn't test the circuit". Also, when I take the tool that you ground then take the light to an electrical component (don't know the name of it sorry) to fuse #11 which is fuel pump I get nothing. First thing I did was change the fuse but I can't get power to it.

[edoc]

Okay made some progress. Just took another paper clip from power at fuse 10 to power at fuse 11 (fuel pump) and it started. Now what?

EDIT: Fixed. Turned out to be a bad connection at the battery junction block. Thanks again for the quick replies guys.