Wiring diagram for an electronic fuel puml circuit

[Tommmmd]

Looking for a wiring diagram that shows the coil - fuel pump - pressure switch - solenoid wiring. I'm getting wrapped around the axle on what should be a very simple circuit, to figure out why I am not getting voltage to my fuel pump.
Engine runs just fine, thankyou, with the priming bulb.

Tom

[JOHN COOKSON]

Have you tried bypassing or shorting across the OPSS?

TRUE GRIT

[Carl-T705]

If you haven't got pressure to the pressure side of the switch, the current will not flow through the switch

[Tommmmd]

fuel pump wiring

Yes I did, but the fuel pump did not activate when I turned the ignition on as it has before when I jumped the OPS, and still no voltage.

Thx, Tom

[Marian Claire]

Electrical stuff is not my best but have you checked the ground for the fuel pump? Dan S/V Marian Claire

[JOHN COOKSON]

Yes I did, but the fuel pump did not activate when I turned the ignition on as it has before when I jumped the OPS, and still no voltage.Thx, Tom

Sounds normal to me - or maybe I'm missing something.
The OPSS is a "normal open" switch.
There should be no voltage to the fuel pump unless A)the key or switch is on AND B)the oil pressure is up.
Some engines have a wire from the starter that is cojoined with the wire to the fuel pump so electricity is supplied to the fuel pump while the engine is being cranked before it starts and the oil pressure rises.

TRUE GRIT

[Tommmmd]

fuel pump wiring

Yes
1) ignition is on
2) switch is jumped
3) wired both to the starter solenoid and the coil.

solenoid - OPS - Fuel Pump - coil
(which looks odd to me, why I'm looking for a wiring diagram)

Power thru the single wire, ground thru the mounting bracket.

no voltage.

Why is it wired to both the starter & coil? Mind you, its been wired like this since I bought it 10 years ago, & yes, its been run a few times. I have had need to jump the OPS before & its run fine with gator clips & wire. Never had reason to check the voltage.

Removed the alternator to get it rebuilt this winter, periodic maintenance.

Still, looking for a wiring diagram. I have a few examples, but not much detail for an electric fuel pump.

May have to keep hopping below to squeeze that bulb!

Tom

[JOHN COOKSON]

Tom
Here's the wiring diagram from my late model A4 owner's manuel.
A fuse between coil + and the OPSS would be an excellent idea.

TRUE GRIT

[Tommmmd]

wiring diagram

Thx much for the diagram. My fuel pump is wired on the coil side of the OPS. I should check there is no in-line fuse, could explain no voltage. I spent all my time looking on the solenoid side for faults.

Tom

[Tommmmd]

Wiring diagram

Thx again John, I am A DA. You hit the nail, I had installed an inline fuse on the fuel pump 8? years ago & had forgot. Sure enough, that was it.

I took the alternator off & may have sparked it sometime checking the connections, It is charging just fine, so no other damage done I can tell.

Tom