Help: M50 Cranks But Won't Turn Over

[tomgt325]

You need to get a better idea of what your lacking; spark or fuel. i would test the lines leading to the crank sensors, and the coils, via the dme hub. i think that will be the most telling information.

I'm lacking both fuel and spark. And I'm not positive what you're referring to when you say dme hub. Diagnostic port that's close to the dme?

I'm almost leaning towards having two bad ecus. Pretty crummy luck, and slim chance, but otherwise I'm at a bit of a loss.

[Chrisv006]

This reallllly sounds exactly like what I was going through...even the fuel pump getting power with the ignition off.

A new main relay cured everything.

By the way - what year e30, what m50 motor, what ecu and how about your x20 -> c101 pinout? Id post my huge long toubleshooting list of things to check but I want to make sure it applies to you and wont just lead you down the wrong path.

[dirty30]

dme doesn't need to be grounded.

lol

[gregslow318i]

what motor is this, m50nv or m50tu? have you ome'ed out the crank position sensor? (check to see if the sensor is good)

[tomgt325]

what motor is this, m50nv or m50tu? have you ome'ed out the crank position sensor? (check to see if the sensor is good)

Yea I checked both the cam and crank position sensors, and they both read the correct resistance.



Question: Does running a wire from the dme to the strut tower ground provide a temporary proper ground?

[tweetyoost]

yes it does, I did actually the same.
I think you can check the quality of the ground by measuring between the chassis and the brown wire (pin 30 or 87 i think) on the white relay.

Does the white relay comes on if you put the key in ignition stand? that's the start of everything..

[monkeytaco]

Power Distribution Block:

There should be a ground coming out of that harness and connected to the shock tower ground point. It looks like you have way too many wires connected to your power block. Can you take more detailed pics of all your grounds?

[328ijunkie]

What fuel rail are you using? Does it have the pressure regulator on it?

[tomgt325]

What fuel rail are you using? Does it have the pressure regulator on it?

stock and stock


BUMP for pin chart on first post!! Plz take a gander

[Grant01]

lol

The case of the DME really doesnt need to be grounded, mine is currently laying in the glove box touching nothing metal

[Grant01]

stock and stock


BUMP for pin chart on first post!! Plz take a gander

Im guessing you have a mixup on one of your wires and its potentially not getting the ECU to get power. When i did my swap i just bought a connector, so i cant actually help with that as im not familiar, but i really feel your problem is somewhere in that bundle of wires

[RobertK]

Sounds a lot like the problem I had years ago with my first swap...

http://www.r3vlimited.com/board/showthread.php?t=120499

Solution was posted on the next to last page though I'm not sure if your car would suffer from the same issue.

[chibich]

status update

[psyber_0ptix]

do you have your charcoal canister hooked up properly? The last picture you posted....the one where you said you had no idea how it's connected....


There should be a evap line coming near the fuel/return that then connects to that little check valve. The check valve connects to the charcoal canister and the charcoal canister connects to the intake manifold.

If you hooked the checkvalve directly to the manifold or capped it then the tank will go under vacuum and will fight against the fuel pump.

I made this mistake having deleted the check valve and it would crank, injectors actuated, but would get no fuel to let it turn over.

I left the evap line open to atmosphere and blocked the port on the intake manifold with a little rubber cap and clamp. little valve remains plugged into the harness

i really hope this helps, as it frustrated me for hours.

[tomgt325]

I checked a few more things, and this is what I know so far: Pin 13 gets no power, and I can jump the relay to turn the fuel pump on. Pin 7 (DME power) gets power when the ignition is turned on. Assuming the relays are good, Pin 13 getting no power means the ECU is not sending it right? Both crank and cam position sensors are good, and I've swapped out relays, so that leads me to believe that the ECU is bad. Does this sound logical to you?

Sounds a lot like the problem I had years ago with my first swap...

http://www.r3vlimited.com/board/showthread.php?t=120499

Solution was posted on the next to last page though I'm not sure if your car would suffer from the same issue.

Thanks Robert, but I don't have pin 7 on the x20 hooked up, and pin 15 is needed for the starter in my case.

There should be a ground coming out of that harness and connected to the shock tower ground point. It looks like you have way too many wires connected to your power block. Can you take more detailed pics of all your grounds?

One of the wires connected to the power block is redundant: I have two running from the fuse box, one from the starter, and one from the harness. The extra one is running from the wire that connects to the starter (it splits off). I was told there is no use for this one, so I just attached it to the block assuming no harm no foul. Hopefully I'm wrong on this one.

Does anyone have a pic of their power distribution block?

I went and checked today and I found that all red wires get a constant 12v, and all red wires w/ white stripes only get power when the ignition is turned on. I was lead to understand that this is what is supposed to be happening.