car is fucking DEAD, plz help

[CorvallisBMW]

So the eta LeMons car has taken a sudden turn. After getting the i cooling system installed, the dash and heater box removed and the suspension on, I went to fire it up and drive it out of the garage.

It cranks very strong (battery has been on a tender and reads 13.1V) but doesn't start. My dumbass realizes the ECU got unplugged during the dash removal so I plug it back in. I crank it again, for about 10 seconds. Still spinning strong but not starting. I wait 30 seconds, try cranking for 15 seconds. Nothing. Wait 60 seconds, try cranking for 20 seconds. Still nothing. I kept trying for a few minutes, giving the starter some time to cool down between tries.

At this point I realize that when I turn the key to position 2, I don't hear the fuel pumps priming. So I start checking all the fuses. Everything is good, nothing blown or missing. Only relay #K7 is clicking though when I turn the key to position 2.... shouldn't the starter relay and fuel pump relay both click? I swap a known good relay in for the fuel pump but no change. *sigh*

Anywho, after checking fuses and swapping relays to make sure all were functional, I put everything back where it was and try cranking again. This time I get absolutely NOTHING, not even a peep from the starter. Number K7 Relay is still clicking, but other than that I get SHIT ALL. Nothing from the fuel pumps, the ICV, the starter or the ECU. All fuses still good.

I know nothing about the electronics of the starting system in this car.... can anyone help to point me in a direction where I should start looking?

[jlevie]

A E30 doesn't "prime the pump" when the key is turned to RUN. The fuel relay only closes when the DME sees timing data from a rotating engine. Look to power to the DME and the timing reference sensors.

K6 & K7 are the unloader relays and on this car they should close when the key is in the RUN position.

The fact that the starter isn't now operating suggests a problem with the primary power connections, the ignition switch, or the starter. There is no starter relay in an E30 other than the solenoid that is part of the starter.

[amiller07]

i had the same sort of problem...check your crank shaft sensor...because if it is bad or not positioned right the coil will not send a spark.....as for the starter thing im not sure there.

[e30Squid]

Have you checked to make sure you are getting spark? If so, and you are then move on to the fuel situation.

I am not sure on the ETA cars, but on the "i" cars there is a block of 3 relays under the hood next to the drivers side strut housing...these are the fuel pump, main, and DME relays (might be off on one of those labels). I would start by swapping those out with known good relays.

If still nothing, and you have access to a spare DME then I would swap it in and see what happens. Reason I say that is I had a similar problem with my 944...I was backing out of the driveway and it died, and would not start. Cranked good, Spark was good, but no fuel....tried swapping in a spare DME I had and it started right up. I would hate to see someone swap fuel pumps to find out it was a relay or dme.

Good luck.

[CorvallisBMW]

I already tried swapping DMEs and there was no change, so I think I can rule that one out. We also installed new reference sensors a month or so back when we first tried to get it running. Since then it has sat in the garage, I'd be surprised if one or both failed while just sitting there (but stranger things have happened). It was hard for me to test for spark without someone else there to help watch while I cranked the engine, but it did not appear that I was getting spark.

[CorvallisBMW]

Thanks to some awesome help from Luke, we tracked down the problem.

Somewhere between the ignition switch and the main relay was a break in the wire, so the main relay wasn't seeing any power when the key was on. Hence no start. Ran a new wire from the relay to the switch and everything works great!