No Spark No Fuel

[Hoffbrohaus]

1990 325is, M20B25. Car was running fine yesterday and I decided to check the compression for a misfire issue I am troubleshooting. So I disconnected the positive wire on the coil, pulled plug wires & plugs, then pulled the fuel relay. All cylinders were fine, around 150. Put everything back together and went to bed.

This morning I was ready to go to work and the car just cranked, wouldn't start. Checked everything I disconnected previously, jumpered the fuel pump relay and the fuel pump worked.

What could it be? It cranks fine, just sounds like no fuel. If the jumpered pump works does that mean it could be the relay? would disconnecting the relay and plugging it back in fry it?

[Hoffbrohaus]

Ok got home. Tried starting the car with the fuel pump jumpered, pump was pumping but car would not start. Pulled plug wire no spark.

Followed bentley to test main relay and had no voltage at the air stabilizer valve but did have voltage at the supply wires to the relay so I would think bad main relay.

Question is I pulled a 5 pin relay from my fuse box to test in the main relay socket and that didn't work but should it?

[5Toes]

compare the two relays you used - on the sides of them should be the diagrams with pins 30, 85, etc.

[Hoffbrohaus]

I get voltage to the fuel pump relay with the main plugged in. If the main was bad should I still get voltage to on the fuel pump relay?

And yea the other relay matched on all pins except 86 and 30 were swapped. So that's a no go. Anywhere to find a matching relay just to test it?

Sent from my SM-T230NU using Tapatalk

[Hoffbrohaus]

Ok just had my wife pick up a new main relay for me while at work. Assuming she put it in right she says it still will not start.

Summary:
No spark
No voltage at coil
Voltage to main relay fine
New main relay
Jumpered fuel pump works
Jumpered fuel pump while cranking won't start (no spark)

How can I have no voltage to the coil?

[Hoffbrohaus]

So I found some old jlevie posts and did more testing. At the ECU I have power to pin 18 with the key out and in the on position. I do not have 12.6 volts at pin 27 however, not even 1v in the on position. This is supposed to have power with the ignition on. So I checked Pin 7 of C101 per jlevie, sure enough same .4v. now I have to figure out why.

Pin 27 = Start input- to ignition switch and from OBC
Pin 7 on C101 = Switched power Ignition switch

back to Google :(

[Hoffbrohaus]

Ok here's the latest in case anyone is reading this...I could use some help.

Since my voltage was low at the C101 harness and not on the green ignition wire I figured it was something in between.

I found this in a thread regarding the OBC relay box "Turn the ignition to run. Check for 12V on the C2 connector's green/red wire and green wire. If the first is dead, you aren't getting power from the ignition switch. If the green wire is dead then there is an issue with the relay. If the green has power then the relay is not your issue."

So I had voltage on the green wire but not on the green/red. I jumpered the 2 wires and low and behold the car started. Why wouldn't the red/green wire have power?

[Hoffbrohaus]

I feel like I'm talking to myself. In case anyone else has this issue, I just soldered the two wired going into the obc relay together. So no obc relay and the car starts fine.