HELP! Where is the lift pump?????fass 150/150

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propilot

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Ok everyone, please hold the laughter back. (LOL) I have a 04 2500 HD LB7.
I keep loosing prime after about an hour of the motor not running. after it starts, it will run for about a minute and then die of fuel starvation. i reprime the the system on the filter and it will start and run great. no problems excellerating hard or at idle. i think the lift pump is on its way out. Is the lift pump in the tank, or is it mechanical? Is it part of the fuel guage sending unit? there are only 2 wires going to my fuel tank. also i have a fass 150/150 pump system i want to put on it. reading the directions it doesnt say anything about removing the lift pump. thats why i wonder if it is in the tank. if it is in the tank, will the lift pump abstruct the fass pump system from bringing the fuel out of the tank? also, the fass pump kit gave me a filler neck with a return pipe thats about 1 inch to small for the filler tube. has anyone run into that problem or did they just send me a wrong part? the truck is mostly stock, except edge with juice, bd manifold, electric radiator fans, banks air intake and 5" turbo back exaust. i also run no-mor friction in everything. that stuff really works. it gets 18mpg in town and 22 hwy.

Any feed back would be greatly appreciated. Thanks
 
dont know on a chevy follow the fuel lines if it wasnt in the tank you would see it, the two wires that go to the tank should only be for the fuel guage
 
You'll be looking a long time to find a factory lift pump on the early Duramax powered trucks...They didn't have one..LOL
 
Well, i have found out that if i park the truck up a hill with the nose high, the it will loose prime, if its down hill (nose down) it will not loose prime. and runs great. so im starting to think its a check valve problem. but i have no idea where the check valve would be on this thing.

so is the fuel pump (not the injector pump) mechanical or does the injector pump provide the suction for the fuel from the tank.

does anyone know where i can find a sevice manual for this thing. cant find anything for this truck at the auto stores!!

thanks for the feed back fellas
 
it provides suction you might have a loose fuel filter or a bad gasket on the filter its worth checking the filter
 
propilot said:
Well, i have found out that if i park the truck up a hill with the nose high, the it will loose prime, if its down hill (nose down) it will not loose prime. and runs great. so im starting to think its a check valve problem. but i have no idea where the check valve would be on this thing.

so is the fuel pump (not the injector pump) mechanical or does the injector pump provide the suction for the fuel from the tank.

does anyone know where i can find a sevice manual for this thing. cant find anything for this truck at the auto stores!!

thanks for the feed back fellas
Click to expand...

Injection pump is electronic..(Often referred to as the CP3)

The filter heads have been known to have issues on these trucks, and I believe there is a check valve in the head assembly...I could be wrong about that though.

Helm makes the complete service manual for your truck. They're very through...But also expensive. Your local dealer can get you one, but I believe they're around 200 dollars new.
 
"Injection pump is electronic..(Often referred to as the CP3)". <--- mine is gear driven (CP3) and crates a suction from the tank, unless I have my Lift pump turned on. Lift pumps on Chevy's are an aftermarket add on. You might be having a problem with the WIF sensor on the bottom of the fuel filter not sealing all the way (Pass side near firewall). The filter itself, or the priming vent might also be leaking.
 
The fuel pump and the injector pump are 1 unit.
Check valve is in the filter head.
www.Helminc.com these are the factory service manuals.
Sounds to me like the filter head is leaking.
 
On a common rails they're a high pressure pump, not a injection pump.
 
:bangWell, I changed the filter and the o rings, still having the same propblem. nose up, it looses prime. nose down, no problems.:bang.

if i take the filter head off, can i get to the check valves and clean them out really good. i used a whole 16 oz can of sea foam 2 tanks ago. when i changed the filter, it was full of crud and stuff. the old filter is about 2500 miles old. im wondering if some crudd got into the check valves and keeping them open. any way to clean these things.

the feed back i have gotton from everyone is great and i relly appreciate it. keepem comming please. Jon
 
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propilot said:
:bangWell, I changed the filter and the o rings, still having the same propblem. nose up, it looses prime. nose down, no problems.:bang.

if i take the filter head off, can i get to the check valves and clean them out really good. i used a whole 16 oz can of sea foam 2 tanks ago. when i changed the filter, it was full of crud and stuff. the old filter is about 2500 miles old. im wondering if some crudd got into the check valves and keeping them open. any way to clean these things.

the feed back i have gotton from everyone is great and i relly appreciate it. keepem comming please. Jon
Click to expand...

Sounds to me like your filterhead is shoot. That happens. I would look into getting a new or used filter head. Or you could just go to a lift pump with an aftermarket filter setup(which is what I did). I completely removed the OEM filter head and check valve. No issues sense. I mounted pump and a standard filter head under the cab. I used a Wix replacement of a Standard Cat fuel filter.
 
:banghead::bangWell, i took the 3 month old filter head off, disassembled it cleaned it thourally, put it back togeather, put new hose clamps on it, got it running, parked it nose high waited 2 hours and it died again after 30 sec of running. primed it up again and parked it nose down waited all night started it up in the morning and it kept running with no problems. Any sugestions????? im running out of ideas areas to go.

could the pump be going out. where would i look for an air leak????

Help.

thanks, JON
:bang
:banghead:
:frown:
 
Does anyone know if the fass 150/150 flter system have a way to keep the system primed when not running. i.e. does it have a check valve or flapper valve like the stack filter head does. im thinking of bypassing the stock filterhead with my fass syatem i havent installed yet. im waiting on my filler neck from fass. they sent me the wrong size with the kit.

thansks
Jon
 
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