Dual tank problems

[jobob307]

I have a 98 1 ton with dual tanks. The problem is it pumps fuel out of the front tank over flow. But of course only when it feels like it. And of course the stealership wants 1500 to fix:eek:

[grancito]

When you switch tanks, ¿do you just hit the change button or hold it down for a couple of seconds? The switch over is driven by a motor and changes the fuel return as well. You could be getting a partial change over and hence pumping fuel from one tank to the other.

[jobob307]

There is no switch. It is NOT like the 6.2 from the eighties. It has dual tanks but is supposedly all automatic. When it worked you could fill one tank and by the time you left the pump it would have moved the fuel to the other tank and the gauge would read half. I know it's weird I have never seen another one like it. The stealer wants to put in a new dash cluster, both tank sending units, and a fuel control box.

[grancito]

Sounds complicated, too many automatic things these days, I´m suprised that we are not all broken down in the dessert.

[jobob307]

Well I got some time to work on this truck again. I found out it has 2 lift pumps one for each tank and also still think it is the front tank sending unit causing the problems.

[grancito]

with 2 lift pumps there must be a system choosing which tank will be pumped from. I agree partly with the "stealer" senders and control box, but one at a time. Try checking the resistance of each sender, but you need to know the fuel level in each tank is the same.

[jobob307]

I agree I ordered a front tank sending unit today. When checked with a meter it read open all the time.

[grancito]

That's good. Quick, and cheaper than the other alternatives.

[tree.stalker]

I have a 98 1 ton with dual tanks. The problem is it pumps fuel out of the front tank over flow. But of course only when it feels like it. And of course the stealership wants 1500 to fix:eek:

Did you have any luck with fixing the problem. I have a 98 1 ton also but it will not pump from the rear tank.

[GM Guy]

Operators manual says fill front tank 1st, back tank 2nd. I think that fuel is always pulled from front tank, and the second tank keeps the front topped off until 2nd tank is empty. Bet there is a computer box involved somewhere.
i would only suspect computer box, not dash & sending units.

Dads 1998 chassis cab gasser has 22 gal front tank, and 18 gal rear. when @ 1/4 tank, front tank will take about 10 gal, back will take full 18 gal.

[torque454]

Do they not have room for one big tank? Lot of extra stuff to go wrong having two small tanks. Doesnt really make alot of sense.

[GM Guy]

No kidding! all that extra stuff just for 6 gallons?! :eek: A regular pickup can have a 34 gallon tank, and the twin tank chassis cabs are only 40 gal!