I'm at a loss. maybe you guys will know.

[upstate6.9]

Ok so here is the deal.. my truck keeps dying after running for awhile. Runs the filter out of fuel or close to it after about 30 min to an hour. I can't seem to figure it out for the life of me... it's a pain in the .... now that winter is here it's how I make money and with the lack of shoulders to pull over on when it cuts out I'd like to fix it lol..

Here's some background. I inherited the truck from grandpa he bought it New in 84 and I believe it has the snow fighter pack with a hydro Fisher plow. Has around 84 and change on the clock it's whole life has been in New Hampshire, Connecticut and upstate ny. Only ever used for dump runs plowing and hauling wood. Been taken care of fairly well.

Anyway it sat for last 5yrs after the lift pump went. New pump, battery, filter hit the key and she ran off a 5gal jug. Replaced all the fuel lines and so on. No cold start issues at all. 8 deg out this morning 2 cycles of the gp's an she fired off with a few sec of cranking. Only ever have issues after it runs for awhile. Could the heat from the exhaust be messing with the fuel in the lines? ( I've only seen that in old gassers) When I 're did the lines I followed the old path which do go near the exhaust but not super close. All my clamps are tight. I don't think I'm sucking air in anywhere. And it has 3/4 to full tank.. I'm looking for a 55gal tank for in the bed incase my tank is shot.

Sorry for the long story lol any help will be much appreciated

 

[Clb]

There is a lot of info on these issues already posted.
But are you at 1/4 tank? Showerheads
Does it have fuel? Bad gauges.
Does it switch tanks? Fsv
Why the 5 gal jug?
Either the fuel is not coming up from the tank.
The switching valve could be an issue.
Of the lift pump is shot( brand new china is known to fail)
After this it gets interesting.
Get it inside and dry' start at the tank and go forward, check everything.
Get a fsm, or book.

 

[upstate6.9]

It only has the front tank.. rear tank was Swiss cheese. Fsv is no longer on the truck.. it has almost a full tank of fuel.. Why the 5 gal jug.. was only used when I first started it after it sat for yrs. It has since been several months only now that I'm using it more often I noticed it dies after running for awhile (empty the filter) but 're primes and fires.. no problem. It cold starts very easy and runs strong. The lift pump is the mechanical pump that is recommended by several members.. I understand that doesn't mean I didn't get a faulty one.

There is a lot of info on these issues already posted.
But are you at 1/4 tank? Showerheads
Does it have fuel? Bad gauges.
Does it switch tanks? Fsv
Why the 5 gal jug?
Either the fuel is not coming up from the tank.
The switching valve could be an issue.
Of the lift pump is shot( brand new china is known to fail)
After this it gets interesting.
Get it inside and dry' start at the tank and go forward, check everything.
Get a fsm, or book.

 

[Dsl_Dog_Treat]

Was the rubber line at the lift pump replaced at time of pump replacement? Need to do a flow test from the Schrader valve off the filter head to see what's going on there. My guess is you're going to find that new lift pump has failed or a hardened cracked rubber line because the IP is sucking the filter dry so it's not getting enough fuel under load. I had a brand new Carter mechanical lift pump fail 660 miles into a family vacation after dealing with a cracked line to the lift pump. Never leaked a drop of fuel but introduced enough air that the IP was starving.

 

[icanfixall]

You seem to be sucking air. Can't telll you from where either but. Please replace the snort rubber hose from the frame rail to the lift pump. If that rig has the original hose I'm sure its cracked and sucking air. Then I suspect the failed new lift pump issue. some new lift pumps are terrible these days.

 

[upstate6.9]

I'll go back over the lines and triple check them.. I was a bit frustrated this morning when I did the op after having to mess with it making the job longer and colder than it should of been.. so here is a bit more detail..

Fuel line is new from tank to pump. Clamps are tight.. The fsv is gone as well as the rear tank (looked like Swiss cheese) lift pump is new (I know that doesn't mean it's not the problem) New fuel filter.. has between 3/4 to full tank according to gallons not gauge.

What is driving me crazy is. It starts up super easy. (8deg this morning 2 cycles of the gp and it kicked off) runs fine I can drive it around plow. Do 55 down the rd easy. Then after about a hr give or take it'll sputter out. I can crank it to 're prime and when the filter is full it'll spit fuel out the Schrader across the engine. And 're fire without a issue. And then 45min later does it again.

Is it possible that the heat from the exhaust manifold is causing it? I've seen that happen on old gassers didn't think diesel would do the same.

I guess I just need to find a in bed tank and get another lift pump asap..

 

[Clb]

How are ya verrifing the fuel filter is dry?
Try the heat soak trick...
Pour some cool h2o over the ip to cool it down, when it dies. Altho this usually happens after shutdown and restarting.
What size line from tank? Did you check the returns all the way back ?
Try some low psi air front to back ( behind the lift pump).
I've got aunt's in oswego, and wauntau(sp?)l.I.

 

[typ4]

I just repaired a sending unit for a friend that had a pinhole in the steel line where it comes out of the tank. Just a thought.

 

[subway]

I just repaired a sending unit for a friend that had a pinhole in the steel line where it comes out of the tank. Just a thought.

That's actually what I tracked my stubborn air leak down to. Out of curiosity how did you repair it? I tried throwing some epoxy on it during vacation when I was 600 miles from home but it didn't work.

I was thinking of cleaning it up with some acid to eat the rust and trying to silver solder it.

Sent from my SPH-L720 using Tapatalk

 

[F350camper]

only other thing i can think of is Make sure you have the correct fuel cap and that it is still venting properly.

 

[typ4]

That's actually what I tracked my stubborn air leak down to. Out of curiosity how did you repair it? I tried throwing some epoxy on it during vacation when I was 600 miles from home but it didn't work.

I was thinking of cleaning it up with some acid to eat the rust and trying to silver solder it.

Sent from my SPH-L720 using Tapatalk

Thats what I did.Silver solder.

 

[ironworker40]

Leave fuel cap off and see if it still does it. If it stops then pull vent on tank and check it and hoses for spider nests and replace fuel cap. What did you use for new fuel lines and as already posted what sizes did you use? I would go ahead and change lift pump again or go electric.

 

[Agnem]

Best way to troubleshoot this... hook up a fuel pressure gauge where the fuel line feeds the IP. If you can't monitor your fuel pressure, everything you do is just a guess and probably a huge waste of time. You need to do this because.... if the IP is original, it could have a deteriorated governor band, and all these efforts to make sure it is getting fuel will not help at all. A Stanadyne IP with the symptom you describe could certainly be just that. Pretty rare these days, but the early pumps were built that way.

 

[upstate6.9]

What am I looking at for pressure at the ip? The same 5 to 7psi I should be getting out of the lift pump.

Best way to troubleshoot this... hook up a fuel pressure gauge where the fuel line feeds the IP. If you can't monitor your fuel pressure, everything you do is just a guess and probably a huge waste of time. You need to do this because.... if the IP is original, it could have a deteriorated governor band, and all these efforts to make sure it is getting fuel will not help at all. A Stanadyne IP with the symptom you describe could certainly be just that. Pretty rare these days, but the early pumps were built that way.

 

[upstate6.9]

As for the lines same size as stock 3/8ths I think.. rubber connections and the nice hose clamps that don't pinch. I'll give it a shot without the cap on see if it changes anything...

Anyone in Oswego county with a decent size tank I can stuff in the bed? Lol