Truck won't stay running on rear tank?

[apextrans]

I know the tank is full. It runs ok for a few minutes then I start getting these power surges.....like its running on NOS or something. Come to a stop & it idles rough. I pull away still running crappy, it clears out then just acts like its out of fuel & dies. If I switch to the front tank, it will start back up and run crappy for a few seconds then smooths out. It has done the surge thing a few times on the front tank though. Is this the begining of IP or injector failure? I don't have the means to test injectors. I know the IP has been leaking a little prior to the turbo install this past spring. Why would it only act up when its on the rear tank though? Is it something else?

 

[DeepRoots]

i get the same thing when I start running out of fuel.
so I'd guess there is probably an air leak in the line from the rear tank up.

does it do it when the rear tank is full? if so I'd guess the leak is out of the tank.

just my guess,
drew

 

[wwwabbit]

Check for air first. Another thought is when my tank selector failed, it did it part way, so it allowed some fuel to come from the tank, but none to return to the tank. The "from" was restricted too, so idle and low RPM was good, but at higher RPM's it was starving for fuel (plus return was blocked so that put everything funny all the way around.

 

[rancherman84]

check the two fuel(or four for dual tanks) lines that are between the tanks and switching valve,the lines off of the tanks are hard plastic then they switch to steel and back to hard plastic where they hook to the switching valve,mine had rotted out at the steel parts along the frame rail,at idle the truck would surge and stall,but after a little throotle it would be fine,just remember,you could have the air leak and no fuel leak,mine was so small until i started poking and pulling the lines the fuel leak was hardly noticed

 

[pafixitman]

Did you fuel up recently? Different station? Mine got the surges and I recalled I had run out of power service coming back from SC. Added a healthy dose and all was well.

 

[apextrans]

Man, I wish this had happned while it was warmer out!! I got alot of "outside under the truck" time ahead of me I guess. I don't know what the tanks look like as far as rotting. I guess I'll check the plastic & steel lines first. Is it common for the switching valve to go bad? Someone locally suggested that too. I have done about 1000 miles in the truck in the last week, which is more than I drive it in 2 months, and have fueled at a few different places. I trust the fuel at those places because those are the truckstops where I fuel my Peterbilt. But, the last two fill ups have been at the usual local place. This all started after the long runs? How much is the switching valve? Oh, the power surges are very strong. Could there also be fuel system problems? I would LOVE for the truck run like it does when it surges!!

 

[pafixitman]

Scott,
I know with my surges, it was about 600 rpm jump. And yes, it is cold outside!

 

[apextrans]

So far tanks look ok. I didn't pull the bed off, but had it off when the truck was painted. Have to check the lines next. Drew, the tanks is full so you're saying the tank itself could be sucking air?

Isn't there a pickup pump in each of the tanks? Could the rear pickup be bad? The gauge doesn't register on the dash either (been that way since I had the truck) Prices on the switching valve is pretty pricey.

 

[towcat]

My vote is on the switching valve. Your year truck should have plastic lines except where the tank is at. If you were reporting these problems with the feul level below 1/4 tank, then your feul pickup foot would be suspect. When my switching valve died, the resulting pressure was high enough to blow off my return lines at the plastic fittings.

 

[DeepRoots]

I said:
"does it do it when the rear tank is full? if so I'd guess the leak is out of the tank"

english doesn't seem like it should be my first language
I meant, outside of the tank, not 'out of the tank'
either way, I was just relating to my truck doing the same thing when it starts to run low on fuel (bout 145miles into it)

dp

 

[apextrans]

I said:
"does it do it when the rear tank is full? if so I'd guess the leak is out of the tank"

english doesn't seem like it should be my first language
I meant, outside of the tank, not 'out of the tank'
either way, I was just relating to my truck doing the same thing when it starts to run low on fuel (bout 145miles into it)

dp

I'm with ya now. I thought you meant the tank itself. What a PITA that would be. Towcat, if it is the switching valve, is there any way to test it before dropping $150 -200.00 (non returnable after plugging in) to be sure? Where is this thing mounted? Chiltons doesn't mention it. Thanks again guys

 

[wwwabbit]

On the inside of the frame rail, driver side, about middle to rear of the door if I remember right. I got one from a u-pull wrecker for $20 that worked. You might find something like that.