Won't Start

Post Sat Oct 22, 2011 5:24 pm

Hi guys, engine turns over fine, I'm getting fuel at the injector rail and the plugs smell of petrol so think it's getting fuel OK.

I don't think I'm getting a spark so I'm thinking possibly crank sensor.

Where the crank sensor plugs onto the loom it seems to be under the inlet manifold. I can see a couple of connections next to each other. At the moment the crank sensor is plugged into the one nearest the bulkhead, is this correct? Are those two plugs the same and therefore is there a chance that they are the wrong way around?

Cheers

Greg

Post Sat Oct 22, 2011 8:37 pm

M50 plugs are the same and can therefore be plugged in incorrectly, M52 have different cam & crank sensor connectors, so you can't get them the wrong way around.

Post Sat Oct 22, 2011 9:06 pm

Sorry, should have said. It's an M52. Sounds like my sensors can't be plugged in the wrong way round.

I have no reason to think the crank sensor is dead, other than the fact that it's been transferred from another engine. What's the best way to test it?

Any other suggestions any one?

Post Sat Oct 22, 2011 9:52 pm

One other thing, is not having a temp sensor connected up enough to stop it from starting?

Post Sat Oct 22, 2011 11:05 pm

You have got the original key and EWS setup haven't you?

Don't think the temp sensor would make any difference

Post Sun Oct 23, 2011 9:06 am

Yep, EWS clicks as soon as the battery is connected. The fuel pump primes, I'm pretty sure the fuel pipes are connected the correct way round (I've tried them both ways anyway).

Post Sun Oct 23, 2011 10:49 am

earth strap fitted to engine?

Have you done the loom yourself or bought it from Dan?

Post Sun Oct 23, 2011 3:04 pm

greggers wrote:Yep, EWS clicks as soon as the battery is connected. The fuel pump primes, I'm pretty sure the fuel pipes are connected the correct way round (I've tried them both ways anyway).

Its not difficult to identify which fuel line is which, take them both off and work the fuel pump briefly, the supply pipe will spray a bit of fuel, much better than just swapping them round until it works

Post Sun Oct 23, 2011 5:24 pm

Well this morning I made sure all the relays were clean and tested them all. When I put them back in and turned it over I could tell it wanted to start, but wouldn't quite fire up.

By this time a friend had arrived who's a dab hand with BMWs, the inlet manifold came off (M50 inlet on M52) and we set about checking all the vaccuum pipes and ensuring the inlet was sealing to the head. Low and behold when we connected it all back up we turned it over and it went and the second attempt.

Connected up the throttle cable, it now idles perfectly and seems to start on the button.

Now time to connect up the exhaust and prop, fill and bleed the brakes and clutch, fit the rear disc setup, sort out the radiator, temp gauge, find a fan that will fit and tidy up the wiring some more.

Still, very pleased that it's running.

Post Sun Oct 23, 2011 6:07 pm

Well done, just the fanny jobs to do now by the sounds of it.