I have a 05 crew 6.0 auto 4x4 doolly. It has the trip and mileage computer in the insturment cluster. I have a 100 gal aux tank that the truck assessories dealer told me not to tie into my factory gauge because it will screw up the computer. well every time i run on that tank after a while the check engine light comes on. I took it to the dealer and the told me it was a over fill condition in the fuel tank. so we figured out thats what was causing it. It was under warranty no charge. well the 2nd time it did it I took it in again not knowing what it was and it was a overfill condition. This time it was not under warranty $75.00. Does anybody know the cure for this condition? Evenfully the check engine light goes out buy it self after a tank runs through the main tank but I hate driving with check engine light on It drives me nuts.
AUX tank problems with my 2005. help
- Thread starter edsf460
- Start date
CHPMustang
Senior Member
Any possibility of running an independent fuel level gauge for the auxiliary tank to get away from the stock tank issues?edsf460 said:
Bill
95_stroker
Jefe
I guess I am confused, is the 100 gal tank tied into the factory guage or not?
Joe G
SDD Junior Member
edsf460 said:
Sounds like someone screwed up the installation. I have an 05 F350 with a 45 gallon tank in the bed tied to the stock fuel gauge. I have a switch on the dash to switch from one tank to the other. Both work perfectly.
Joe
Tail_Gunner
CRJ & ERJ A&P Mech.
I also have a 100 gal aux. tank in the back. I have a separate gauge for the aux tank. I got a digital gauge that reads in percent. So a gauge that read in percent for a 100 gal tank is basically telling you the actual approx quantity of fuel in the aux tank.
As for tieing in the aux fuel tank into the truck's fuel system, I put a "Y" fitting into the filler neck's vent line. I installed an electric fuel pump that transfers fuel from the aux tank to the main tank's vent line. I also put in a fuel filter ahead of the transfer pump to protect the pump from foriegn "crud". By doing things this way, I was able to minimize cutting into metal fuel lines and didn't have to worry about plumbing in some P.I.T.A. transfer valve.
It has worked very well. The one significant short coming is having to VERY CLOSELY monitor the transfer to prevent overfilling the main tank. I use a kitchen cooking timer on the sun visor to time transfers.
The main tank fuel gauge is very slow to come up when the main tank is getting refueled. You may have noticed this at a regular gas station. The trick is to know about how many gallons down you are when the needle is on the "Full" mark, 3/4 mark, 1/2 mark etc. In my case when the gauge is right on the full mark, the main tank is about 9 gallons down from completely full, 3/4 mark is about 15 gallons down. For my transfer pump, I use 1 minute= 1 gallon. So if the main tank says 3/4, I transfer fuel for about 15 minutes.
As for tieing in the aux fuel tank into the truck's fuel system, I put a "Y" fitting into the filler neck's vent line. I installed an electric fuel pump that transfers fuel from the aux tank to the main tank's vent line. I also put in a fuel filter ahead of the transfer pump to protect the pump from foriegn "crud". By doing things this way, I was able to minimize cutting into metal fuel lines and didn't have to worry about plumbing in some P.I.T.A. transfer valve.
It has worked very well. The one significant short coming is having to VERY CLOSELY monitor the transfer to prevent overfilling the main tank. I use a kitchen cooking timer on the sun visor to time transfers.
The main tank fuel gauge is very slow to come up when the main tank is getting refueled. You may have noticed this at a regular gas station. The trick is to know about how many gallons down you are when the needle is on the "Full" mark, 3/4 mark, 1/2 mark etc. In my case when the gauge is right on the full mark, the main tank is about 9 gallons down from completely full, 3/4 mark is about 15 gallons down. For my transfer pump, I use 1 minute= 1 gallon. So if the main tank says 3/4, I transfer fuel for about 15 minutes.
Last edited:
W4RLR
High Tech Hillbilly
Joe G said:
As long as both tank sizes were EQUAL, or nearly so, that should work. He has a 100 gallon tank. I think that is the cause of his problem. I'm pretty sure that the computer is programmed for the approximate size of the installed fuel tank(s) from the factory. I have a 30 gallon tank in my truck. If I add another 30 gallon tank, and a double pole double throw switch to the dash to change tanks and route the fuel sender signal to the dash gauge, I could double my range and not bother with reprogramming the computer. If the 100 gallon tank could be split in half with two senders, and a three position switch to include the factory tank, that might solve the problem, assuming the truck has a 45 gallon factory tank. IMHO.
W4RLR
High Tech Hillbilly
You could also rig an electric pump that would transfer fuel between your auxiliary tank and your main tank. If you have a spare upfitter switch, wire the pump to this switch. Transfer fuel as if you were actually making a fuel stop. The truck would not know the difference, and the gauge would slowly come up. Do this when your truck is at rest and your main tank is nearly empty, and monitor the fuel gauge. When the gauge reads nearly full, turn the switch to off. You can do this when you're taking a rest break or a food stop.
