Help: M50 Cranks But Won't Turn Over

[tomgt325]

Pics on post 4

Okay, so I'm so close to being done with my M50 swap, I can taste it. But I've ran into a snag in the final stages. I'm not getting fuel or spark. From what I've gathered from searching is that something is telling the DME to not start. I checked both the crank and cam position sensors and both are good. I swapped DMEs to no avail. I've swapped relays, I've triple checked my wiring, and I'm pretty sure the engine and ECU are grounded. I'm at a loss guys....any suggestions?

Here's a video of it cranking if that helps at all.

http://www.youtube.com/watch?v=2UCDA5sF2ZI

Here is my pin chart, I believe this is correct, but I hope I'm wrong......

'91 318is C101 - '94 325i x20

pin:color - pin:color

1:blue - 25:blue
2: x
3: x
4:brown/white - 12:brown/violet
5:brown/green - 23:brown/grey
6:green/yellow - 22:green/white
7:green - 21:green
8:white - 24:white/black
9:black - 20:black
10: x
11:white/blue - white/green
12:brown - 8:grey
13:green/blue - 13:green/violet
14:black/white - 14:black/white
15:black/green - 15:black/green
16:white/black - 17:white/violet
17: x
18:black/yellow - 18:black/yellow
19: x
20:red/yellow - 22:green/white

Thanks in advance guys!

-Tom

[Fusion]

Fuel pump getting power?
The DME tends to shut down spark when it finds out the pump isn't working.

[tomgt325]

Fuel pump getting power?
The DME tends to shut down spark when it finds out the pump isn't working.

When I bypass the relay and jump it, the fuel pump gets power. I switched out that relay with a diff one and nothing changed.

[tomgt325]

Fuel lines:




Power Distribution Block:






Starter:




Could it be these shitty connectors?




Here's the adapter:

(dont mind that green wire I snipped)




For the life of me I can't remember where this went?

[George77]

Check if you get power to the coils or if the main relay is triggered on or if the fuel pump relay is triggered on as well,you can check if you get power on the green unfused wire if not then right next to the abs ecu there is a black box ,that black box has 4 wires ,two of them are green, try to jump those two wires and see if it's going to start or at least trigger the main and fuel pump relay and if it does then that relay has a burn circuit inside,I can't remember in this second the name of relay but it's related with the OBC( you can put a password code in the OBC and if you want to start the car and you don't put the code in the OBC ,the OBC will not trigger that relay and the car won't start.

[tomgt325]

Check if you get power to the coils or if the main relay is triggered on or if the fuel pump relay is triggered on as well,you can check if you get power on the green unfused wire if not then right next to the abs ecu there is a black box ,that black box has 4 wires ,two of them are green, try to jump those two wires and see if it's going to start or at least trigger the main and fuel pump relay and if it does then that relay has a burn circuit inside,I can't remember in this second the name of relay but it's related with the OBC( you can put a password code in the OBC and if you want to start the car and you don't put the code in the OBC ,the OBC will not trigger that relay and the car won't start.

I have a 6 button OBC if that matters. Trying this tonight.....

[Cook]

Does the engine have the EWS immobiliser system?

[tomgt325]

Does the engine have the EWS immobiliser system?

No, I'm using a red 413 dme

[dirty30]

Is the case of the dme grounded?

[freeski27]

I would double check your fuel pump situation. My case was a bit special because I started with a shell, so the wiring was completely random. But I was having that problem and it was because the fuel pump wasn't getting power. Should put a multimeter to the power source at the fuel pump and turn the key to run. (sounds like you know this already, but I'm just checking).

You should actually be able to hear it prime the system if you just turn the key to run...

[tomgt325]

Is the case of the dme grounded?

Literally ran a wire from the case to the strut tower grounding point just in case. I also bolted it up too.

I would double check your fuel pump situation. My case was a bit special because I started with a shell, so the wiring was completely random. But I was having that problem and it was because the fuel pump wasn't getting power. Should put a multimeter to the power source at the fuel pump and turn the key to run. (sounds like you know this already, but I'm just checking).

You should actually be able to hear it prime the system if you just turn the key to run...

I've jumped the relay and the pump will get power, but it still won't turn over b/c of the lack of spark...

[blackhawkimpact]

DME doesn't need to be grounded.

[Chrisv006]

Have you tried to jumper the main relay then start? 30 to 87/87a.

That ended up being the broken part for me.

[tomgt325]

Have you tried to jumper the main relay then start? 30 to 87/87a.

That ended up being the broken part for me.

I jumped both the fuel pump, and the main relay and it still did not start.



Something weird happened as well, when I jump the fuel pump relay the fuel pump starts even if the key is in the ignition turned or not. Is this supposed to happen?

[call me jack]

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.