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Lift Pump Not Working, Where to Start

I agree the fuel system pressure have to be build up.
I would also make sure that the LP is on all the time during this process.
Start by bleeding the LP to FFM first and keeping the LP on crank the engine with some GP out with some pause to cool starter.

Make sure both batteries are strongly charged.
 
Alright pulled the glow plugs on the driver's side and loosened and cracked all 4 injectors on the same side. Cranked numerous times. Had my son crank while I watched and no fuel is coming out of the injectors. Lift pump is definitely working. Can hear it and fuel squirts out the bleeder valve when opened.
 
Disconnect the line from the metal tube, put the clear line end into an empty bottle.
crank it over as if to start. See if it flows freely. If so, your return line to the tank is plugged.

If it does not flow freely out the ip return while trying to start - you either have blockage of fuel supply or bad ip.

so the test after that would be removing the input fuel line to the ip. Check flow and pressure at that location.
BE 100% IT IS NOT THE LINE FROM THE FFM TO THE IP!!! That line being bad has caused SO MANY people to replace a good ip.
That is the reason I scream always have a fuel pressure gauge tapped at the ip inlet with no rubber line after the tap.
 
Btw- that fuel looks like crap in the pic. Once you solve the fuel flow issue, or during, pull a quart sample into a glass jar and let it settle a day to see what is in it causing that horrible color.
 
Will L. said:
Disconnect the line from the metal tube, put the clear line end into an empty bottle.
crank it over as if to start. See if it flows freely. If so, your return line to the tank is plugged.

If it does not flow freely out the ip return while trying to start - you either have blockage of fuel supply or bad ip.

so the test after that would be removing the input fuel line to the ip. Check flow and pressure at that location.
BE 100% IT IS NOT THE LINE FROM THE FFM TO THE IP!!! That line being bad has caused SO MANY people to replace a good ip.
That is the reason I scream always have a fuel pressure gauge tapped at the ip inlet with no rubber line after the tap.
Click to expand...

Are you saying not to test the line from the FFM to the IP? Or are you saying to make certain that line is not bad?

Right now it has the elbow fitting to the IP with the rubber line from the FFM connecting to that.

Fuel has been sitting in the tank for the 2 years the truck has been in my backyard.
 
What is important to make it run is fuel should flow out the ip return at almost the same rate going into it. The injectors all barely use a shot glass worth of fuel at idle in about a minute.

Massive flow through the ip from inlet to return is required to make the pump operate.
 
There's also a screen in the IP fuel inlet fitting itself, have you checked that for contamination? I see you upgraded the hose fitting that goes into the IP, the screen is part of the fitting that your sweep 90 screws into.
 
DieselAmateur said:
There's also a screen in the IP fuel inlet fitting itself, have you checked that for contamination? I see you upgraded the hose fitting that goes into the IP, the screen is part of the fitting that your sweep 90 screws into.
Click to expand...

That fitting is from a Feed The Beast kit, albeit the rubber hose version.
 
Alright, I think we’re narrowing this down. First pic is after disconnecting clear return line from hard return line then cranking the engine for like 10 seconds. Second pic is the fuel pressure gauge connected directly to the fuel hose from the FFM to the IP after cranking for 10 seconds.

B1A49B87-DA89-4F4A-BA82-A7872A96F61D.jpeg0D63AD4A-8C4E-4EEA-AD9B-5D7998B4674B.jpeg
 
I'm talking about this fitting, it has a screen over it and sits in the IP. You can see the screen standing up in the background on the housing neck. Did you do away with this fitting when installing the FTB kit? I've never seen one plugged, but it could be gummed up from fuel sitting in it for a long time
 

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The compound meter looks familiar. I got one just like it... :woot:

So no fuel flow through the IP. That bottle should be like full after 10 sec of cranking.
 
DieselAmateur said:
I'm talking about this fitting, it has a screen over it and sits in the IP. You can see the screen standing up in the background on the housing neck. Did you do away with this fitting when installing the FTB kit? I've never seen one plugged, but it could be gummed up from fuel sitting in it for a long time
Click to expand...

I will pull this tomorrow....after I finish with the carpet extractor. It could have been eliminated when the Feed the Beast fitting was installed. It does not look like a screen, based on the size of the holes in it.
 
The pressure coming out the ffm means he is getting fuel out through that screen most likely.
How long to fill that bottle where you have the pressure gauge hooked up?
Show a clear pic of that just to make sure.

Something is happening where the ip is not letting fuel flow through properly.

I am short on sleep right now and can’t analyze how to test flow through the ip- but should be a lot of flow out that ip return line.
Could swesr there is something to check before condemning the ip..
 
Feed the IP out of a 5 gal bucket including the return line. This eliminates the entire fuel system on the vehicle. It's IP vs. bucket, one loose known good lift pump, and two known hoses. (Another forum just had a small diesel genset with a 1980's DB2 stop running in seconds due to a restricted return line. Of course they rebuilt the IP first just to be sure it was something else cheaper.) If all else fails you have a 5 gal bucket of fuel to burn it. :angelic:

So with the shut off solenoid removed you had good fuel flow out of that hole with the lift pump running? I thought you did and that's fuel past all the screens. RIP for the IP if so.

The screen in the IP is a ? as well as the last ditch screen in the FFM.

I assume you are tapping off the water drain for lift pump pressure. I did the same. The rubber hose flapper on the inlet to the IP was a real PIA to find.

BTW: The screen is set down over here...

screen.JPG
 
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