1985 325e no spark no fuel

[scalabroni97]

I plugged and unplugged what i thought to be the c104 located near the ecu. Here are some pictures (sorry for the bad quality, this was as big of a file as I could upload). Everything that is necessary seems to be connected.

When I test voltage at the coil, I am testing while the car is getting cranked or does it not matter?

[RobDog]

Here are a few things to check:

1) Swap Crank Shaft Position sensors. I engines have the sensor on the front/passenger side of the engine and it reads off the harmonic balancer. The harmonic balancer can separate into 2 pieces causing no spark. The Eta engines have 2 sensors in the trans bell housing on the drivers side. They read off the flywheel. There is a metal weight that one sensors reads on the flywheel that can fall off causing no spark. Look through the sensor hole with a flashlight while someone slowly turns the engine over. Ensure that the weight is there.

2) Main relay: under the hood on the drivers side near the strut tower will be 3 relays. They may be under a cover. The forward/lowest relay will be the main relay. The main relay is not your standard relay because it has two 87 outputs. This relay turns on 2 outputs and does not switch between outputs like your standard relay. Makes sure you have the correct relay and that it is working. If it has 87a on the bottom than it is the wrong relay.

3) OBC lockout: The OBC code function can cause random no spark/fuel. Under the drivers kick panel, behind the abs computer(big shinny silver box), is a small black box with 2 green connectors. The connectors look like the door chime plugs but green. In those 2 green connectors there are about 6 wires. The 2 largest wires are green and green/red. Splice the green and green/red wires together to bypass the obc relay. This will ensure that your engine electronics are getting full voltage since this is the voltage supply to the main relay.

4) Check the fusible link in the trunk, Located on the smaller wire that runs parallel with the main battery cable in the trunk, about 10 inches back from the positive terminal.

5) Try swapping computers with a known working one just incase you are having ECU problems.

[e30sh]

When I test voltage at the coil, I am testing while the car is getting cranked or does it not matter?

It needs 12v in start and run but I normally only check it in the run position.

If your fusible link wire has blown, you can move the lead it feeds over to another hot post on the junction block.

Verify the OBC relay box is good. There was a thread on here a few weeks back about it.

[borrihong]

Since you were under the dash; have you disconnected and reconnected your ECU to ensure it's seated?

[scalabroni97]

2) Main relay: under the hood on the drivers side near the strut tower will be 3 relays. They may be under a cover. The forward/lowest relay will be the main relay. The main relay is not your standard relay because it has two 87 outputs. This relay turns on 2 outputs and does not switch between outputs like your standard relay. Makes sure you have the correct relay and that it is working. If it has 87a on the bottom than it is the wrong relay.

3) OBC lockout: The OBC code function can cause random no spark/fuel. Under the drivers kick panel, behind the abs computer(big shinny silver box), is a small black box with 2 green connectors. The connectors look like the door chime plugs but green. In those 2 green connectors there are about 6 wires. The 2 largest wires are green and green/red. Splice the green and green/red wires together to bypass the obc relay. This will ensure that your engine electronics are getting full voltage since this is the voltage supply to the main relay.

4) Check the fusible link in the trunk, Located on the smaller wire that runs parallel with the main battery cable in the trunk, about 10 inches back from the positive terminal.

5) Try swapping computers with a known working one just incase you are having ECU problems.

I have tested the main relay and it is working. I will check the OBC next time i'm at the car.

Could my car even crank without a fusible link???

I would try swapping the ecu if I had another laying around. But I will unplug and plug it back in to make sure its connected well.