Dual Tanks, Switch and Fuel Gauge

[IDIDREW]

Truck: 1992 F250 XLT Ext. Cab Dual tanks

I thought I was running low on fuel ~1/4 tank left indicated on the gauge. So I switched from the rear tank to the front tank and the fuel gauge did not change position.

I went to the Gas Station, and started to fill the rear tank, and the pump clicked off after a couple gallons. I thought that was an error so began to fill once again, it clicked off right away. Rear tank was full.

I then began to fill the front tank, it took 14 or so gallons.

Should the Fuel gauge change position depending on which tank you select, front and rear? Is this a signal that the fuel tank switch is bad? Any further testing that can be done?

Thank You!

 

[79jasper]

It should switch when you switch tanks.
Search here, many threads on the tank selector valve.

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[IDIDREW]

The tank selector valve is a submissive device to the switch correct?

My initial thought was to Diagnose the switch first and valve second. I am hoping the valve is ok and the switch is the issue (wishful thinking).

Sending unit could also be the culprit but I would think the fuel gauge would drop if the switch was working and the sending unit was bad.

My initial diagnosis is this: Fuel is being consumed from the front tank, this means the fuel selector valve is set to the front tank (regardless of switch position). Either the switch is bad (not signaling the valve/sending unit to use fuel from the rear tank) or both the valve and the switch are bad. My hypothesis is that both need to be replaced.

OEM Tank Selector Valve ~300
Switch ~30-50 (amazon, rockauto, etc)
Sending Unit ? (haven't priced it out yet)

 

[79jasper]

Typically the valve fails before the switch.
The valve itself is what swaps tank readings.

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[madpogue]

http://userpages.chorus.net/elephant/FuelTankSelector.pdf - for a 1995, but it's pretty-much the same. Switching motor (as evidenced by the diagram) is based on polarity. Easy test is to run 12V directly to those two terminals, reversing polarity, and listen for the valve to operate.

 

[tradergem]

The last time I had to replace my fuel tank selector valve, I didn't have time to wait for a $300 original ford part and ended up using a $70 universal tank selector valve from Oreilly's.
The only real problem with the universal tank selector valves is that they have hose barb fittings not the quick connect fittings for our trucks still using the original fuel lines.
I used some steel quick connect fuel repair lines from Dorman and cut them to length and used them to connect to the universal tank selector valve with short pieces of rubber fuel lines and hose clamps. Also note that some of the universal tank selector valves use a different electrical connector that you have to buy separately.
Good luck.

Jim

 

[Mike Linger]

I'm going to replace my fuel selector valve tonight. I am not excited about diesel fuel running all over my face as I do the change. I think I'll unbolt the valve from the frame first and let it hang down while I do the connector changeover to the new one. I guess I'll smell like diesel for a while but from what I understand they actually make a cologne for men called Diesel. Hhhmmm, wonder if it smells better than what's in my tank.