RetroTek EFI - electronic fuel pump problem

[65 Fastback]

I have the RetroTek EFI system on my new 347 stroker. Sunday I had the engine started and running, but the alternator bearing was SCREAMING, so I couldn't bring the engine up to operating temperature. I pulled the alternator and ordered a new PowerMaster 1-wire alternator. So I replaced my alternator Wednesday, but the battery was too low to turn the engine over. Thursday night I hook up some jumper cables to my Explorer and the engine turns right over but the electronic fuel pump never comes on.


The only thing I have done since the engine was running Sunday was to replace the alternator - and now the electronic fuel pump won't come on - it ran fine on Sunday. The first thing I did was check the fuses - all fuses good.

OK, so I ran some tests on the electric fuel pump today.

- If I add a ground to the pump (-) terminal, I still cannot energize the fuel pump from the ignition.

- With the new ground in place, if I jump from a 12V source to the fuel pump (+) terminal, the fuel pump is energized.

- Now if I remove the additional ground from the fuel pump (-) terminal and jump the (+) terminal with 12V and the ignition in the off position - the fuel pump does not energize.

- But if I remove the additional ground and jump (+) with 12V and the ignition in the on position, the pump energizes.

So I know the pump is good. So do I have a short in the wiring harness, a bad ground or is the computer bad?

Any guidance or other testing procedures appreciated.

Thanks,
Tim

[camcojb]

how does Retrotek control the pump? Most of the aftermarket systems just control the ground to the fuel pump relay to turn the pump on and off. The pump has it's own ground, and when the computer grounds the relay it sends 12v to the pump.

Your testing of jumping the pump direct should have turned it on, but it didn't unless you added a separate ground. At that point I'd say your pump ground is bad, but you got it to work with an extra 12v jumper, no extra ground, and the key on. That makes me think the computer controls the ground of the pump somehow (not just the relay like all the others I've seen), or there is a problem in the wiring that gives a ground circuit to the pump if the key is on.

Can you tell us how they wire the pump?

Jody

[65 Fastback]

Thanks for the quick reply Jody.

This is the RetroTek "returnless fuel line" system. There is just a fuel supply line, no return line. The computer pulses the fuel pump to maintain the correct PSI.

The fuel pump is wired directly from the computer, one ground and one 12V supply.

Tim

[camcojb]

Thanks for the quick reply Jody.

This is the RetroTek "returnless fuel line" system. There is just a fuel supply line, no return line. The computer pulses the fuel pump to maintain the correct PSI.

The fuel pump is wired directly from the computer, one ground and one 12V supply.

Tim

so the computer supplies both power and ground to the pump? Sounds like that's where I would be looking. Check all the computer grounds, make sure one wasn't removed with the alternator R&R. For the heck of it check your config section in the computer software and make sure the pump is enabled, how long for it to run with key on, etc. in case disconnecting power for the alt swap reset or cleared something (shouldn't have, but if the grounds look good that's the next thing I'd check).

Jody