Fuel Pump Replacement

[WahooSteeler]

Fuel pump died, picking up a Delphi FE0108 tomorrow. Has anyone installed one of these? Wondering if it's a direct fit or needs modification like the Bosch unit. 

[WahooSteeler]

I realized that I still have the Renix XJ pump that I used temporarily when I had TriStarr refurb my FSU. I've tried to sell it with no luck, so is it safe to say I could use that as my replacement pump? 

[WahooSteeler]

Before I pull my existing sending unit, I am trying to troubleshoot other possibilities to make sure the pump is getting power since my assumption that it is dead is because the truck died while driving it and I don't hear the pump coming on. I back probed from the harness side of the fuel pump and am getting 4v with the key on or when trying to start. Should I be getting more voltage??

[Ωhm]

7 minutes ago, WahooSteeler said:

I back probed from the harness side of the fuel pump and am getting 4v with the key on or when trying to start.

Do this voltage reading again but this time disconnect fuel pump motor.

[WahooSteeler]

11 minutes ago, Ωhm said:

Do this voltage reading again but this time disconnect fuel pump motor.

 

If you mean for "fuel pump motor" to disconnect the fuel pump harness, 6.3v. And fyi, my battery is low from multiple attempts to start. 

[Ωhm]

2 minutes ago, WahooSteeler said:

If you mean for "fuel pump motor" to disconnect the fuel pump harness,

Yes that.

 

What is battery voltage?

[WahooSteeler]

4 minutes ago, Ωhm said:

Yes that.

 

What is battery voltage?

 

12.8v

 

[Ωhm]

Your dropping voltage somewhere. Bypass (jumper) fuel pump ballast resistor. Take voltage reading at fuel pump harness connector again. Swap relays around. Take voltage reading at fuel pump harness connector again.

[WahooSteeler]

6 minutes ago, Ωhm said:

Your dropping voltage somewhere. Bypass (jumper) fuel pump ballast resistor. Take voltage reading at fuel pump harness connector again. Swap relays around. Take voltage reading at fuel pump harness connector again.

 

How do I bypass the ballast resistor? Jumper between the two wire clips? Which relay is for the fuel pump? I pulled those earlier and they appeared ok, i.e. no corrosion, and I sprayed them with contact cleaner. 

[Ωhm]

6 minutes ago, WahooSteeler said:

Jumper between the two wire clips?

That it.

 

 

6 minutes ago, WahooSteeler said:

Which relay is for the fuel pump?

Relay Block Pin_4 has ORN (orange) wire.

 

[WahooSteeler]

5 minutes ago, Ωhm said:

That it.

 

 

Relay Block Pin_4 has ORN (orange) wire.

 

 

Looking down at it from over the pass fender, which of the 4 relays should it be? Having a hard time getting the relay "tray" unclipped from the holder and don't want to break the tabs. Fyi, I am charging the battery with another car right now, voltage is 7.3v at the harness with or w/out the ballast bypassed. 

[Ωhm]

3 minutes ago, WahooSteeler said:

Having a hard time getting the relay "tray" unclipped from the holder and don't want to break the tabs.

Yea, take your time there. Don't want to break any tabs.

 

4 minutes ago, WahooSteeler said:

Looking down at it from over the pass fender, which of the 4 relays should it be?

Fuel pump relay will have that ORN wire in Pin_4 of the 4 relay blocks.

[fiatslug87]

RENIX 4.0L Relay Center

[WahooSteeler]

Ok. Couple of questions before I proceed.......

 

How much voltage is needed to the pump? Even at only 4v wouldn't the pump come on? 

 

I have some brand new relays that are 30/40 amp I was going to use for the door locks. What amp relays are in the relay tray, i.e. can I just try the new relays? 

[WahooSteeler]

Thanks slug. Swapped w/AC clutch relay, still 7.4v, left fuel pump relay block empty, still 7.4v. Add'l info.......I recently added the extra ground at the tail light, but not at the fuel pump harness. 

[Ωhm]

2 minutes ago, WahooSteeler said:

I have some brand new relays that are 30/40 amp I was going to use for the door locks. What amp relays are in the relay tray, i.e. can I just try the new relays?

I only meant to swap your current relays around. If fuel pump relay was a problem then swap in a different one.

 

4 minutes ago, WahooSteeler said:

How much voltage is needed to the pump? Even at only 4v wouldn't the pump come on?

Electric dc motors that don't spin are a direct short to ground. That why I asked to disconnect the fuel pump connector. No current flow in circuit. Now we're looking for battery voltage along the fuel pump circuit.

[Ωhm]

4 minutes ago, WahooSteeler said:

still 7.4v, left fuel pump relay block empty, still 7.4v.

Is that with engine cranking?

[WahooSteeler]

Swapped all existing relays in to the fuel pump relay block, no change in voltage even with the relay block empty. 

 

Voltage actually drops when cranking by @1v. 

 

Can I put 12v power direct to the fuel pump harness and see if it comes on? 

[Ωhm]

3 minutes ago, WahooSteeler said:

Can I put 12v power direct to the fuel pump harness and see if it comes on?

That should work.

[WahooSteeler]

1 minute ago, Ωhm said:

That should work.

 

So 2 wires from positive and one from negative to the ground wire in the harness? I was going to use a jump box. 

[Ωhm]

1 minute ago, WahooSteeler said:

So 2 wires from positive and one from negative to the ground wire in the harness? I was going to use a jump box.

I'm lost here. Don't understand your hookup.

[WahooSteeler]

Sorry. 3 wires on the harness, was going to simply clamp wire with jumper cables hooked to the battery. Should the positive wire go to the purple, the orange/black, or both? And should the negative wire go to the black ground wire in the harness? 

[Ωhm]

2 minutes ago, WahooSteeler said:

Should the positive wire go to the purple, the orange/black, or both?

Purple wire is fuel pump sending unit (IP gauge). Orange/black is fuel pump motor.

 

3 minutes ago, WahooSteeler said:

And should the negative wire go to the black ground wire in the harness?

Yes

[WahooSteeler]

2 minutes ago, Ωhm said:

Purple wire is fuel pump sending unit (IP gauge). Orange/black is fuel pump motor.

 

Yes

 

Got it.....

[WahooSteeler]

23 minutes ago, Ωhm said:

Purple wire is fuel pump sending unit (IP gauge). Orange/black is fuel pump motor.

 

Yes

 

She spins........was hoping it didn't, would rather just have to swap out the pump than trace wires lol.