Lift pump relay, alternate trigger

[grib]

I've got an ECM that no longer powers the lift pump on an 02 24v Cummins HO.

 

I replaced the VP44 and hotwired the aftermarket lift pump (airdog raptor) to test. Manually supplying power to the lift pump and bleeding injectors did the trick, so now I need to wire it in properly.

 

I read the article on RF noise with aftermarket lift pumps, so I'll modify the harness with a .1 Mfd Orange drop capacitor and modify the pump when I have it out again.

 

 

Given that my ECM lift pump circuit is DOA, where should I grab a trigger voltage to engage the lift pump relay?

 

I am looking at the light green and black wire carrying ignition power at F18 in the first diagram in the engine wiring diagrams post.

 

Is that the best circuit?

 

 

 

[dripley]

Any key on circuit will work. The bad thing is if you have a wreck and rupture a fuel line the pump will keep pumping until you cut if off. The ECM will shut it down if the motor stops turning. Just something to think about.

Edited June 23, 2019 by dripley

[grib]

Fair enough. I should probably use the automatic shutdown relay output for normal operation, and add a momentary manual switch in the cab to run the lift pump after fuel filter changes, etc.

That would mean the trigger comes from the dark green and orange wire from terminal 87 of the ASD.

 

 

There is also something labeled "fuel pump relay" that seems appropriate. That output is red and light green in the PDC (87).

 

This is a common enough problem that it is worth getting right (particularly in view of the safety concerns).

[IBMobile]

1 hour ago, grib said:

There is also something labeled "fuel pump relay" that seems appropriate. That output is red and light green in the PDC (87).

That relay is for the VP44 injection pump.  The red/light green wire powers the pump circuitry. 

[grib]

Thanks, IBMobile and dripley.

 

I think the ASD + manual switch approach is the wisest.

 

It will be a touch more opaque from a troubleshooting perspective than running directly off the Fuel Pump Relay (which is labeled Fuel System Relay on my PDC cover - item 51), but has a safety advantage.

[JAG1]

Also it is important to complete what is called The W-T Grounding Mods in the articles section at the top of the forum. This will help save further damage to expensive electronics. Many have done it and all reported excellent results.