Need help with Fuel pump relay ground...

[nextelbuddy]

just got my S52 engine started today but only after i manually grounded the brown ground wire from the fuel pump relay.

im using an E36 vanos harness with the custom harness adapter from e30polak on here.

can anyone tell me where the fuel pump relay on the engine harness is grounded to so i can find the ground and see whats going on with it?

[nextelbuddy]

just got my S52 engine started today but only after i manually grounded the brown ground wire from the fuel pump relay.

im using an E36 vanos harness with the custom harness adapter from e30polak on here.

can anyone tell me where the fuel pump relay on the engine harness is grounded to so i can find the ground and see whats going on with it?

been searching the forums all weekend with no resolve.

just trying to figure out what it means when the fuel pump relay does not engage with the key in ACC position but will when i manually ground the brown wire from the relay.

[jlevie]

The fuel pump relay receives a ground from the DME when the DME sees timing data from a rotating engine.

[nextelbuddy]

The fuel pump relay receives a ground from the DME when the DME sees timing data from a rotating engine.

ok with that said then theres only 2 things that could cause this.

bad wiring signal between the DME to the fuel pump relay ground via the engine harness or possibly EWS?

i do have a silver label 413 with a TRM chip with EWS delete and read on the forums there was no need to cut anything such as green #7 wire on the driver side plug.

[Adrian_Visser]

Is the pump running when you are cranking the starter? The fuel pump will only run when the engine is turning over. Read Jlevie's answer carefully.

The fuel pump relay receives a ground from the DME when the DME sees timing data from a rotating engine.

The fuel pump not running with the engine off and the key in the acc. position is normal.

[nextelbuddy]

Is the pump running when you are cranking the starter? The fuel pump will only run when the engine is turning over. Read Jlevie's answer carefully.



The fuel pump not running with the engine off and the key in the acc. position is normal.

that doesnt make sense then.

if the DME needs a timing signal to send a ground to the relay then why when i manually ground the relay then start the engine, the engine runs fine.. if there was no timing data/signal getting to the DME then how could the engine run properly when i ground the relay?

obviously my cam and crank sensors are working fine otherwise the engine wouldnt run as well as it does or at all.


all i know is that with out manually grounding the relay i can not start the engine it just cranks and cranks no fuel

ground the relay and engine starts fine.



definately not trying to argue with either one of you and i apologize if it seems that way. i appreciate any and all help given.

[gobuffs]

BMW DMEs complete the ground to the fuel pu
pump. It does not send 12v to the pump. If you are manually grounding the relay you are doing what the DME should be doing.

[Kingb]

What Adrian is saying is that the signal coming from the dme to the relay could be at fault. I always jump the relay when starting the engine after it was just put in. Grab a multimeter and schematic and check your wire from the relay to the dme

[lexx]

Ever find a solution to this? im having the same problem with the DME sending a 12v signal thru pin 1 to the fuel pump relay

[99em1]

Is the pump running when you are cranking the starter? The fuel pump will only run when the engine is turning over. Read Jlevie's answer carefully.



The fuel pump not running with the engine off and the key in the acc. position is normal.

You mean the run position (pos 2) for prime? Then yes. Otherwise fuel pump only runs with DME input.

It's not your crank sensor. And your cam sensor can't cause a no start so rule that out too.

Take a multimeter and see what your DME is sending to your main relay, and subsequently the fuel pump relay.

Unless you know you are getting the right signals to those relays, it's a waste of time to make guesses otherwise as that path has no end.

[nando]

check continuity from Pin 1 of the ECU connector to terminal 85 of the relay.

[lexx]

We disconnected everything, played with the main relay a bit, and put it all back together. Somehow the ECU was sending a 12v signal thru pin 1. Must have had something crossed. Ive got spark and fuel now....still no start :(