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replaced lift pump and doing bleeding procedure...

M

mhixson

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Messages
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Location
Mount Vernon, WA
I've replaced my lift pump with an ACDelco EP158. Hooked everything back up, installed new fuel filter, attached hose to vent on cap, unscrewed vent 1/2 or so. Now I'm turning my key to run and listening to the pump cycle. It does and glow plugs cycle too. I have keyed up many, many times now and I'm still not getting any fuel out the hose. How many times does it take to cycle the pump? I would say the FFM was almost half full of fuel when I inserted the fuel filter so it seems like it'd be full by now.
I'm getting to the point of removing the fuel line from the front of the lift pump and attaching one going to a bucket just to see if the pump is actually moving fuel.
Any other suggestions?
 
A bunch if using the key. But never again leave fuel in the ffm when replacing the filter or removing for inspection.
Always begin by draining it 100%.
The dirty unfiltered fuel gets past the filter. Doing it once can wile the pump.
Drain it now. Lift the filter and reseat it, and begin cycling the key again.
The drain isn’t there to look cool.
Long term buy a relay harness from Leroy with the switch so the ops doesn’t burn out and you just flip the switch with the bleeder loose. When the bubbles stop tighten it and turn off the switch. Worth the money for the headache.
 
I hate to be the one to say this, but verify you installed the lift pump in the correct orientation. one end should have "OUT" scribed on the pump.

you can install it backwards and it will fit. the side marked OUT points towards the engine. these pumps also cannot self prime, they are designed to push fuel but cannot suck unless they have fuel there at the line coming out of the tank. if there is a large enough air bubble trapped in the line before the pump that also might be your issue.

if you are certain the pump is installed correctly, and there is ample fuel in the tank, try unscrewing the fuel line from the pump on the engine side of the pump and using your hand to cover the filler neck use your air compressor blow gun to give the tank some pressure, not much, but enough you begin to see a little fuel coming out of the pump. Too much pressure can rupture the tank. re-connect the line and try again to prime the system.

I have found that on my truck when the tank is near full, the fuel will siphon out from the lines at the lift pump, but if the tank is low on fuel, it does not.
 
Last edited:
Orientation
IMG_9127.jpeg

Draining fuel from FFM; open the small T-handled valve on the Thermostat Housing and run the lift pump. If the rubber hose leading downward is still attached, you’ll want a catch can or, extend the hose to one. Otherwise, diesel puddle time.
This is also a good location for a temp fuel pressure gauge.
You’ll also pull/push the air from the lines while running the pump.

If your truck is a 96/97, there is a lift pump lead between the firewall and the Under Hood Fuse Box.
IMG_9130.jpeg

Jump power to the lead from the A or B aux. power terminals at the under hood fuse box.
IMG_9131.jpeg
 
Sorry, I missed this part of your original post “… removing the fuel line from the front of the lift pump and attaching one going to a bucket just to see if the pump is actually moving fuel.”

Yes, do this to confirm the new pump is operational.
Then the line up to the FFM can be purged of air. Filter bleeder or T-valve.
IMG_0154.jpeg
Photo credit @TurbineDoc
 
Paveltolz said:
Orientation
View attachment 87286

Draining fuel from FFM; open the small T-handled valve on the Thermostat Housing and run the lift pump. If the rubber hose leading downward is still attached, you’ll want a catch can or, extend the hose to one. Otherwise, diesel puddle time.
This is also a good location for a temp fuel pressure gauge.
You’ll also pull/push the air from the lines while running the pump.

If your truck is a 96/97, there is a lift pump lead between the firewall and the Under Hood Fuse Box.
View attachment 87288

Jump power to the lead from the A or B aux. power terminals at the under hood fuse box.
View attachment 87287
Click to expand...
That's where I installed a fused, safety toggle switch on the firewall.

It was very handy.

I'm always surprised that wire isn't mentioned more on the 6.5 diesel pages. They're always talking about jumping the relay and stuff.

I never see anyone else mention using that wire.

I think that wire is on 1996 and newer.
I know it was on the 98 Suburban and a friends 1999 dually
 
The drain valve in my wheel well was slower than a seven year itch so I disconnected the hose to it and drained the FFM all the way. As expected, its rather dirty. Should I pull the FFM off, clean it, and replace all of its hoses?
Also, I can feel the little round screen over the center piece inside the FFM. Any tricks to remove that without damaging it (with the FFM still on the truck)? I know its a cheap little part, but I'd like to extract it as is to see if it is already damaged and how dirty it is.
Thanks again, everyone.
 

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  • ffm.jpg
    ffm.jpg
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mhixson said:
The drain valve in my wheel well was slower than a seven year itch so I disconnected the hose to it and drained the FFM all the way. As expected, its rather dirty. Should I pull the FFM off, clean it, and replace all of its hoses?
Also, I can feel the little round screen over the center piece inside the FFM. Any tricks to remove that without damaging it (with the FFM still on the truck)? I know its a cheap little part, but I'd like to extract it as is to see if it is already damaged and how dirty it is.
Thanks again, everyone.
Click to expand...
I'd squirt it with some brake clean and call it good.

Get a snake light/ camera or attachment for your phone - if you have a smart phone.

I use an old electric fuel pump / retired lift pump, to clean out stuff like that.

I used to primarily use SeaFoam. I've found that brake clean, cleans better.
 
Will L. said:
Heater hose pliers VERY carefully can pop the final screen.
Yes brake clean but I rinse with a lil clean diesel afterwards all out the drain. Don’t want that cleaner in the ip.

View attachment 87301
Click to expand...
After brake clean I frequently use Amsoil metal protector, Marvel or Sea Foam.

Just because they're handy.

If I get Brake Cleaner on paint or plastic, I always squirt with something more friendly. MP, plastic lube, electronic lube or Simple Green
 
Paveltolz said:
Orientation
View attachment 87286

Draining fuel from FFM; open the small T-handled valve on the Thermostat Housing and run the lift pump. If the rubber hose leading downward is still attached, you’ll want a catch can or, extend the hose to one. Otherwise, diesel puddle time.
This is also a good location for a temp fuel pressure gauge.
You’ll also pull/push the air from the lines while running the pump.

If your truck is a 96/97, there is a lift pump lead between the firewall and the Under Hood Fuse Box.
View attachment 87288

Jump power to the lead from the A or B aux. power terminals at the under hood fuse box.
View attachment 87287
Click to expand...
I tried this and nothing happened. What could be the problem?
 
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