m50 turns over but wont start. Fuel problem?

[Oz10]

So last night I finally had everything together and went to crank my m50 swap for the first time. The starter will spin and the engine will turn, but it won't fire up.

I've tried replacing the fuel pump and main relays that are on the m50 wiring harness. I replaced the fuel pump fuse in the e30 fuse box too.

I've also switched the main and return fuel lines to see if they were in the wrong place.

It doesn't look like the lines are getting fuel, which makes me think the fuel pump isn't running.

Has anyone experienced this or have any suggestions on what the problem may be?

The engine is a m50nv and the car is a 89 325is. Thanks!!

[e30s50dan]

Sounds like you need to first start at the pump and see if you got 12v. Then go from there. What you could do is spray a little starting fluid in the intake but remove your maf first , spray and see if it wants to start,then go from there. Good luck

[gregslow318i]

your crank and cam position sensors are switched at the harness and the dme is not seeing a rpm signal....hence no pump voltage

[Oz10]

I really appreciate the help guys! I'll check it out tomorrow.

Keep the suggestions coming!

[Oz10]

Looks like the plugs aren't sparking either. Could it be a ground?

[Adrian_Visser]

your crank and cam position sensors are switched at the harness and the dme is not seeing a rpm signal....hence no pump voltage

He's onto something there.

[Oz10]

He's onto something there.

I didn't mess with either of these sensors though. I'm wondering if maybe the plug on the otherside is undone. I have a three pronged plug under the intake area and I have no idea where it goes. I guess I'm going to take the intake manifold off and see if anything looks off under there.

[gregslow318i]

I didn't mess with either of these sensors though. I'm wondering if maybe the plug on the otherside is undone. I have a three pronged plug under the intake area and I have no idea where it goes. I guess I'm going to take the intake manifold off and see if anything looks off under there.

what color are the wires on the plug that is not connected. also have you checked the crank position sensor (ome'ed out or replaced with a know good one)

[Oz10]

The wire to the plug that isn't connected is black. Ill try to take a picture of it. Would the crank sensor cause it not to spark?

[tweetyoost]

Hi!

I'm at that same problem, but it's in a 1985 320i Euro chassis.. (with the old electrics:p )
I've put the (external)fuel pump directly at 12v to make some pressure. And then tried to start but it looks like the fuel injectors aren't working.. And I guess the DME won't work aswell. I'm trying to figure it out as soon as possible.. I keep watching this topic ;)

So... you can mix the crank and camshaft sensor? hmm I didn't touch them..

[gregslow318i]

The wire to the plug that isn't connected is black. Ill try to take a picture of it. Would the crank sensor cause it not to spark?

no, you need to peal back the boot covering the end portion of the plug to expose the wires under the black wrapping

[Oz10]

I pulled back the boot and the wires are blue/white, blue/green, and brown

[Oz10]

Does anybody know what that plug is for?

[416stroker]

Take a pic of the plug

[RSGM]