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I’m going to guess that the fuel system was regulated at the pump and the return looped behind the pump and back into the supply. This is just based on some other flow dynamics that I’m familiar with on unrelated pump systems. Maybe the FPR was gutted to send all pressure back to the pump which was then regulated and dumped into the supply side?
Glad you got it home. I was gonna say, I would have purchased enough fuel line to run it back to the house with them plumbed into a jug in the bed. It’s no fun working away from home/tools/shelter/heat.
You’re on the downhill stretch now.
Its that or the return was mostly non functional. The return pipe i think was jammed right up to the fuel regulator piston, and this prevented most flow.
When i took it off to do the seal, this allowed movement in the piston, probably because the pipe moved or wasnt right against the piston.
I think the truck shut down when the piston sleeve/insert thing popped out, resulting in no fuel pressure/the pump couldnt draw from the tank properly, because there was a steady flow of return fuel. The pump would then draw fuel out of the bowl and tank, and probably caused issues (which i think this caused the surging sounds). This was worsened as i tore stuff apart and the pump needed to prime.
This is my guess. Seems like its more of a paradox than a functional system. Regardless, im dropping the factory tank tonight to get it ready and run new rubber lines, and then ill ditch the second tank.
This is an excursion so i didnt want to do the ol gas can fuel tank in fear diesel would spill in the interior. The girls would never step foot into it again unless i got only the best detail. The truck does have 2 tanks, so i had my pick to which one i used to get home lol. Its all 3/8 rubber fuel line so all i had to do was add some barbed couplings and hose clamps.
Once there was fuel pressure, it fired right up.
That icp is leaking bad now. It is visibly leaking out. Hopefully that gets here very soon. I still need to find a pig tail. Having trouble find a brand name one. They are mostly the dormans, and i think i have had enough issues with dorman stuff on this vehicle (though its rated very well on multiple sites).
In a sense, its good all these issue came up when they did. This should keep the truck moving for years to come. It was always on the list to look at it deeper, but if it aint broke....
I thought the pump is supposed to make on the order of 100psi before regulation?
It had a vegetable oil conversion, which means a second tank (for diesel) and then the stock tank was used for the alternative fuels. You start and get the motor warm on diesel, then switch to the alternative fuel. You had to remember to switch it back to get the alternative fuel out of the fuel system before shutting down. There are way better systems out there today.
I personally just used it for extra fuel capacity as there were a fair amount of cost savings as fuel prices varies across provinces. I had no interest in the labour/mess involved using alternative fuels. I bought the truck because it ran pretty good and it was cheeeaaappp for this kind of truck in my area. Diesel was about 40 cents more a liter (maybe 1.4 bucks a gal eqiv) so it was worth it. Personal best was 650 miles with some towing and driving reasonable. That would be about 200liters of diesel.
I wanted a project truck that i could build just the way i wanted it. Also the excursion works very well for our family. Most of the engine BS is done. There will be a gen 3 stage one kc turbo soon. Did a coil swap in 2024. Its all about the interior this year. I need new front seats, and i want the ventilated ones. Im a wizard with wiring and apparently you can get it all working with an arduino. I also want an APU (lifepo4 battery, small inverter, solar panel) for camping and some other accessories (diesel cab heater and diesel coolant heater), and sound deaden the interior more. Reaposlter the middle seats and maybe add heat. New carpet. Get some 120v power, and i want to change the center console for something better with room for aux switches and more functional.
In theroy, i could still use the second tank as a slip tank. So instead of switching tanks, i can run a second pump and fill the factory tank. It would be an extra 24gals or so.
How would you do this? Tee up into the filler neck somehow? What pump would you use (a low pressure pump obviously of some form)? Its only a 3/8 line so it will probably take 20 or so minutes to move all the fuel. I can use the old wiring from the conversion. There is even a timer relay, so i wont forget to stop the transfer.
Got the truck running on the factory tank full time. Pickup was worse than i remember, so i came up with something (don't laugh). I still have the hot fox hooked up. I feel the truck runs better when its as cold as Mars here. Beats buying a new pickup.
I'm of the opinion that if you're never going Veg oil fuel again, just remove all that crap and restore back to just using the main tank. Some work now, but much simpler living from then on while dealing with the fuel station. Unless you have a real need for more fuel storage. How is the Aux tank filled now and does it have a level sender? That could figure into the decisions that you have to make.
My personal experience is that I needed more fuel capacity than the factory tank and purchased an auxiliary tank that fits into the bed of the truck and it came with an automated transfer system that monitored the main fuel tank's level and topped it up as I was driving without me having to keep an eye on it. Very convenient and gave me a LOOONNGG way to be between fill-up.
I do not want to run vege oil. This isnt to argue the merits of running alternative fuels. I just want to run diesel.
The idea would be that the second tank would still be used for fuel, but instead of have a manifold thing switching tanks, im thinking that if the aux tank fed the factory tank, i still get the extra capacity but not the reliability draw backs. The aux tank has a filler neck in the fill port like the stock tank, and it does have a functional gauge.
The idea popped in my head when i drained the aux tank to the stock tank to remove the fuel. I used the other fuel pump that was removed and some 3/8" line and got me thinking. If i could tee it into the stock filler neck (its not stock, its all rubber hose, so making a tee would be easy). It wouldn't be automatic, and ideally i would have some sort of safety. I could use a sbc to make the transfer automatic i suppose, but i was thinking manually. I have some switch legs under the truck already from the old manifold i could utilize for the pump. Im thinking like a carb pump or something that doesnt need to build any pressure.
As mentioned, i do use the extra fuel capacity. I can goto very remote places with the tt, and i frequent a province where diesel is significantly more money, so i can save a few bucks by having more fuel (and laughing at crowded gas stations on a long weekend along the highways).
Remember too that this is an excursion so no option for a slip tank.
Last edited by Hellraiser456; Jan 29, 2026 at 09:48 AM.
I used to have a 1974 Chevy Suburban with the 454 gas guzzler engine
I lived in West Texas and worked in the Natural Gas pipeline business.
my gross pay was $600/month, and my wife's family was in Ft. Wayne, IN....
we would travel up there and back a lot.
I built a fuel tank the full width of the rear compartment, it held 49 gallons of gas.
that tank had a fitting inserted in the left, rear corner, and a Valve that I could turn on/off with a Switch.
when the OEM fuel tank gauge got real low, I turned ON the solenoid and let the Drip Gas fill up the fuel tank. I put a Vapor Lock line from the Filler Neck down thru the floor, to allow the tank to suck in Air,as the fuel was used up.
Worked a charm, as long as, you didn't let it over-flow the bottom tank.
I filled the inside tank with DRIP GAS, the stuff that settles out of a Natural Gas pipeline as it travels miles underground.
the Hot Gas is warm, and the earth is cool, so the moisture drops out, called "drip" and settles in underground tanks, pipeliners would drive a tank truck to the Drip, open a valve and drain the Drip Tank, take it to the Compressor station and sell it to the Refineries.
Last edited by John in OkieLand; Jan 29, 2026 at 10:29 AM.
My 2002 4x4 Silverado 4.8 gets 13.5 mpg whether I'm loaded or not. Having a 454 would only cost me 1mpg if I could go on the memory of my 460 F-250s that I had before I bought the big truck. The 550 diesel only does 14-15 on a good day if I'm not trying to keep up with 75 mph freeway traffic and keep it at 65.
So IMO engine displacement doesn't mean much in the long run.
