M50 conversion died whilst running, no fuel or spark

[redm50]

Hi guys, thanks for your help on the last problem with the heating, now working perfectly, turns out it was the lack of thermostat causing the problem!

I now have a new problem with my 1985 B reg 318i with a M50B25 non vanos conversion, whilst driving I changed down a gear and as soon as I put the clutch in the engine cut out and wouldn't restart. In short I have no spark and the fuel pump isn't pumping.

After getting it back home I pulled a couple of spark plugs out and with them connected to the wiring, turned the engine over on the key but could not see a spark from either of them.

I've checked what I thought was the fuel pump in the tank, which turned out to be just a fuel level sender unit - pre facelift E30, then checked the actual pump under the car, no noise or buzzing to indicate it was running when cranking the engine on the key. Disconnected the wiring to the pump and put 12V leads to it and it pissed out fuel immediately, so pump is working at least.

Next I checked the crank sensor resistance between pins 1 & 2 and got a reading of 494 Ohms. Checked the cam sensor and got 975 Ohms...which I think means both are within acceptable limits?

I was really hoping one of these sensors would be out as now i'm stuck for what to try next...any ideas???


Also on disconnecting both cam and crank sensors I didn't realise they both use exactly the same plug and now I can't be sure I've put them back in the right slot

[redm50]

Also I've checked every relay I could find on the car (not sure if this is the right way to do it) by connecting the switching pins to 12V and listening for the click, all are working fine... fuse 11 is not blown either

[redm50]

The car also cranks over more slowly than I remember, even with a big van battery and a battery charger connected and upped to 180A charging power the engine still doesn't turn over very fast, like the battery is dying but it still shows 12.6V even after being disconnected from the charger for a day

[DanThe]

Have you got 12v ignition feed to the engine loom? If not it will cause the problems you describe

[redm50]

Hey Dan, thanks for replying, I'm going to sound like a total noob but how do I check that? I assume I do have one as it was running before...I unplugged the ECU and there's a lot of pins, is there one in particular I need to check or do you mean the wires that run from the ignition barrel itself?

[redm50]

Ok, so I just checked the ignition feed to the loom, I did this by putting a multimeter from pin 7 to a good earth (I checked it was a good earth by first connecting the multimeter from the + battery terminal to that earth and got 12.6V). I get a reading of 4V...so I guess something is wrong?? I was expecting either 12.6V or 0V but this 4V reading has confused the hell out of me, something strange is going on, unless I'm testing the wrong pin?

[redm50]

Also I did the check with the key turned so the lights on the dash come on

[redm50]

Here's a pic, I just realised that the plug I tested might not be the C101... The plug I tested was the one below with the yellow arrow to it, pin (or hole) number 7... but I also tested pin and hole number 7 on the other plug (which I now understand is the C101...red and green arrows) and both showed 0V with the ignition turned on..

IMG-0967.jpg

Then I found this picture, and tested pin number 21 with the ignition on and got 12.6V - does this mean ignition feed is ok? I also tested pin 18 with the key turned and got 0V

image_125716.jpg

[DanThe]

The plug on the left with the removeable cap is the diagnostic port
The other plugs are X20 from a later car, E36/E34 etc, so its possible your C101 has been hacked out, or is hiding away somewhere out of sight

The best way to check now is by going straight to the coil loom, the round connector plug should have a direct ignition feed to Pin 1, if the car still has most of the E36 engine loom then it could also have a relay near the ECU that powers this ignition feed to the loom