Help, '94 525i won't start !!!!

[Valv]

Hi, newbie here. I have a '94 525i which was running fine until yesterday.
Today I cannot get it to start. It cranks but no fire.
I didn't check spark and I went right away to fuel, since I couldn't hear pump buzzing.
I remove it from tank, cleaned it up, connected it to 12v and it works fine. Re-instrall and I have no juice to connector on top of flange.
Fuses are fine. Where is the relay for the pump ?

 

[epj3]

Your coil went bad, which fried the ecu...go ahead, ask me how i know

(or, crank position sensor is bad. Do you have a multimeter?)

 

[Valv]

Your coil went bad, which fried the ecu...go ahead, ask me how i know

(or, crank position sensor is bad. Do you have a multimeter?)

How do you know ??

I have a multimeter, how do I check it. First of all where is the fuel pump relay, and which color is it ?

I get a puff of life here and there, especially if I let it sit an hour or so.

 

[epj3]

How do you know ??

I have a multimeter, how do I check it. First of all where is the fuel pump relay, and which color is it ?

I get a puff of life here and there, especially if I let it sit an hour or so.

It's not your fuel pump. First find out where your crank position sensor wire goes to (the sensor is at the front of the engine on the balancer wheel, that has the teeth.) Test that for resistance - not sure what it's supposed to be but i'm sure you can find out on the internet.

If that's within spec, check your coil packs, one bad coil pack = fried ECU

 

[Valv]

I have spark on all 6 coils.....before getting into something more expensive I rather chek simple things.

Where is the fuel pump relay, I want to bypass it.

 

[Valv]

Problem solved, I just unhooked battery for 1/2 hour, and left ignition key ON to discharge ECM.

When reconnected car started right away with no problem..........

Go figure.........

 

[epj3]

That's kind of odd - might be the fusible link then.