DME not activating the fuel pump relay

[Crow1970]

Hi All,

I'm ready to throw gas on it and light it on fire, what I have is a 93' 325ic E30, here's a list of all the checks I've made. It does have a new fuel pump and I've jumpered the relay and it spins.

(1) Battery disconnected checked continuity between DME pin 3 and socket 85 of the fuel pump relay, had a reading of .4 ohms so it seems that is fine.

(2) Checked continuity of the relay itself seemed to be ok with an ohm reading of .4 - .5

(3) Checked the ground at the fuel pump relay socket 85 and is good (this is before I plugged the DME back in.

(4) Plugged the fuel pump relay back in and with the key on I have voltage of +13.20 at socket 85 (To my understanding the DME grounds socket 85
when cranking.

(5) While cranking the engine I received a voltage of +.084 (Shouldn't this be a complete ground on socket 85 when cranking and why is there a small amount of voltage present?)

I appreciate any feedback and help you can throw my way.

Thanks

-John

[AndrewBird]

Check for +12V at #30. This is power to the relay for the pump. If you don't have power here, then you have a bad fuse, or bad wiring somewhere along the line.

Also check for +12V at #86 while the key is in the run and/or start positions.

You are seeing voltage at #85 when cranking because you are reading the voltage from #86 through the relay.

With the ECU unplugged and the relay out, you should not see ground at #85. If you do, you have a short somewhere between the relay and the ECU.

I attached a diagram of the fuel pump relay for clarification.