Engine/Transmission (1994 - 1998) Lift pump question

[Flinty]

Just bought another '97 12v. It was a little hard to start and get to idle but with a little throttle it would pop right off, then keep your foot on the throttle for 5 sec and it would find it's stride. Well I'll be darned if that thing didn't die in my drive when I got it home.

Now... the rubber boot on the L. P. primer button is cracked and broken and when I push it there is no resistance offered. Usually when I change the filter on my other one I'll give it quick repetitive strokes with a broom stick into an already pre-filled filter and in short order the by pass valve is squealing. With the new truck- nothing.

I'm putting this out to you guys in hopes of advice=shortcut. The truck sat for a year, has 208k, 5spd, was a little putzy off the line but once the boost came up the power was acceptable. Injection pump hasn't been messed with unless they used another break-off screw and painted it (doubtful). I am the third owner. #2 bought it, decided he didn't need it after all, parked it, sells it 14mo. later to me.

I have Joe's write up and will go that route if no one chimes in.

My first step was a front crank seal and kdp, now I have to get it to start. Sheez!

 

[WDixon27]

when i got my truck some tool had removed the spring and check ball from the of valve so effectively it had no fuel pressure, it was a pain to cold start unless you gave it a few strokes of the primer but warm it would fire off fairly well, but at 300+k miles the lift pump was just about dead anyway, that and all of the various air leaks from the crappy seals on the fuel connections and in the lines going to the afc i am suprised it ran as well as it did

 

[JFaughn]

I would call ?? Mike at Precision Diesel & Turbo , some thing like that , he does not have a web site , that seems to be the only way I can keep track of contacts , bookmarks/favorites , he still may be less than $150 for a lift pump , overflow valve & shipping , thats my guess on what you need .
Fuel pressure test !
Testing saves money , guessing costs money .

 

[tgordon]

Mine did that and it was the lift pump. Now about 100k later sometimes starts hard, but if I give it fuel it will start right up but sometimes when I let it go to idle it will die. I think this time it is either the pump againor the dreaded fuel line rotting. If it is the latter of the two I am thinking I might replace all of it with rubber for ease of instalation.



Troy

 

[Joe G.]

Your idle is too low. The adjustment screw head get polished after a while so the idle drops a little. It should be 800 with the AC on.

 

[Flinty]

I built this contraption to pressurize the tank, etc. With 5psi, the electrical plug on the fuel heater revealed a steady drip. This part will surely find it's way to the round file. I could hear air escaping from the top of the tank. Is this normal via a vent? Thanks for the attention so far.

 

[Joe G.]

There is a pressure relief valve on the fuel tank module.

 

[Flinty]

The sludge on the pre-filter is an indication of the junk found in the bowl. Yet another fuel heater gone to the dogs. Neglected fuel system as a whole. The one pin on the fuel heater was completely fried.

 

[Joe G.]

The black on the fuel filter is a normal stain from the asphault in fuel. It's not a problem. The filter is keeping it from your injection pump which is the whole idea in the first place.



Crap in the pre-filter can be a problem if it gets to the lift pump so it's a good idea to clean it at least once a year.



As you can see, the fuel heater can make you walk. Worthless thing even if it does work.

 

[tgordon]

Joe, I belive the idle is fine, but some times to get it to start I have to tap on the throttle and it will take right off, or start and die as soon as it returns to idle. I am thinging fuel screen plugged, or cracked line in the fuel system as this problem seems to have no ryhm or reason other than if I park with the front of the truck up hill it is worse and I thought somebody else had said that was an indication of the fuel line leak problem



Troy

 

[Joe G.]

If it dies and starts easy with a little bit of pedal then you should set the idle up a bit. The up hill harder starting is a most likely bad fuel hoses. If the hoses have never been replaced or are from a auto parts store they will eventually have to be replaced with good diesel rated hose. The hoses may look fine and have no obvious leak, but still are bad.

 

[JFaughn]

When I had a number of symptoms , one of witch was the up hill / low tank issue , a new lift pump & overflow valve , fix it .
Fuel pressure test .

 

[Flinty]

Fired the truck up last night. I bled #1 & #3, started on the second try. New lift pump, new filter, new screen, fuel heater eliminated. Idle @ 850. Happy day.