At a loss with this lift pump issue.

4x4dually

4x4dually

Moderator
VP44 motor...in a school bus, but basically the same as a 1-ton.

Installed new lift pump. Ran for one bus route, then died back at the barn. Fuel filter canister empty. Filled, primed, started it up and the new pump appeared to be leaking on the top. Removed the new pump and tightened the three screws on top of the pump on the cover, checked all fittings, new banjo washers all the way around, re-installed pump. Sent bus out this morning and it died again. I'm at a loss. WTAF?!?!?

Water separator filter is tight and not leaking. Full tank of fuel in the bus. No drips of leaks that we can see. The new pump came with a pig tail so I installed it and tapped it to a DMM. LP is getting full voltage when running and on starter bumps. 12.8-13.5 VDC. I wigged all wiring from ECM plug 1 to the LP. Doesn't seem to be intermittent on the wiring side, at least not from moving them. Removed the tapped pig tail and sent it out.

Any idears?
 
If it's just the lift pump, why not do the go to fix for the trucks. Put a fass/airdog on it.

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4x4dually said:
I'll let you go to the school board and request a PO for a FASS for a bus. :hehe:
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Use the crusty engineer money and buy it yourself and donate it! Or some of that government subsidy money you big farmers/ranchers are swimming in! ?

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J-Pipes said:
Use the crusty engineer money and buy it yourself and donate it! Or some of that government subsidy money you big farmers/ranchers are swimming in! ?
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You've lost your mind. I've already donated days worth of my time so that my kids and other kids can have a bus to ride. This state has completely f-ed the schools. All this casino and pot tax money the state promised, that some of us saw was a joke and voted against that shit, has never shown up. Schools are broke....at least small, rural schools are. And farm/ranch subsidies? You've gone full retard. With 17 cows we don't qualify for much.
 
I had a funky issue on my 01 where I had voltage but no current. Ran a new wiring harness and issue solved
 
thatguy69 said:
I had a funky issue on my 01 where I had voltage but no current. Ran a new wiring harness and issue solved
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I guess that's a possibility. I was only reading voltage. When trying the starter bump, it pumps fast and furious. I cracked the fuel filter cap and it went everywhere. I just don't know if it's consistent. Might have to wire an idiot light to the cab and drive it around as suggested in a text.
 
4x4dually said:
You've lost your mind. I've already donated days worth of my time so that my kids and other kids can have a bus to ride. This state has completely f-ed the schools. All this casino and pot tax money the state promised, that some of us saw was a joke and voted against that shit, has never shown up. Schools are broke....at least small, rural schools are. And farm/ranch subsidies? You've gone full retard. With 17 cows we don't qualify for much.
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??? it was in jest!

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Apparently, this morning, it started right up. And about 10 seconds later, it lost fuel and died.

There must be an air leak somewhere allowing the water separator or/or fuel filter to bleed back to the tank over night.

I did have to replace the LP inlet fitting with a JIC 37 deg flare when we did it. There wasn't a 45 deg flare anywhere in the country that I could find. Maybe it isn't seated good. It's on the suction side of the LP so while running it should be ok, but while setting, I can see it bleeding back maybe.
 
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There is a campaign available for the bus. Cummins campaign # c0504 This is only for transit bus, school bus, and emergency vehicles.

It addresses a stall condition due to low fuel inlet pressure. This bus does qualify, and Cummins will do the work free of charge. I'll try and email you the file. If I can't make that work, all you'll need to do is call your local Cummins dealer or distributor with your ESN (46057391) and let them fix the bus.
 
Snedge said:
There is a campaign available for the bus. Cummins campaign # c0504 This is only for transit bus, school bus, and emergency vehicles.

It addresses a stall condition due to low fuel inlet pressure. This bus does qualify, and Cummins will do the work free of charge. I'll try and email you the file. If I can't make that work, all you'll need to do is call your local Cummins dealer or distributor with your ESN (46057391) and let them fix the bus.
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Hey, the wife is supposed to be calling your shop to pay for that compressor anytime now. She said she forgot about it before...

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4x4dually said:
Apparently, this morning, it started right up. And about 10 seconds later, it lost fuel and died.

There must be an air leak somewhere allowing the water separator or/or fuel filter to bleed back to the tank over night.

I did have to replace the LP inlet fitting with a JIC 37 deg flare when we did it. There wasn't a 45 deg flare anywhere in the country that I could find. Maybe it isn't seated good. It's on the suction side of the LP so while running it should be ok, but while setting, I can see it bleeding back maybe.
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Does it have any of those pos quick couple connections in the fuel line further upstream?
 
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