tank switching

[franklin2]

is there a write up on the mechanical tanks Swhich mod?

Take a look,, I think there is at the top subforum.

The cheaper valve from autozone will work, but it's not a direct replacement. Needs a little bit of modifications to the line fittings and the wiring to make it work, but functionally it's the same valve.

The other guys are correct you can hear the valve when it works. Mine makes a pretty good thump when it switches that I can hear in the cab if the engine is not running.

 

[ericwade381]

Idioit how's that look now. Thanks!

 

[IDIoit]

atta boy!

 

[ericwade381]

Ok guys so I can hear the click when I switch tanks but my gauge doesn't move... so I wonder is my gauge bad or is It not switching

 

[The Warden]

Ok guys so I can hear the click when I switch tanks but my gauge doesn't move... so I wonder is my gauge bad or is It not switching

I've been having the same problem for about a year and a half now. It happened suddenly and I lost readings for both tanks, so I ruled out the senders (I've since electrically verified that the senders are working as they should), and someone suggested that the seals went bad and flooded the valve with diesel fuel, so that the internal electrical connections for the sending units weren't making contact. I replaced the valve, and still no reading from either tank.

I'm not sure what the problem is, but I suspect that, in my case, the instrument voltage regulator went bad (none of my other electric dash gauges ever worked)...but, IIRC '87 and newer trucks don't have an IVR, so I honestly don't have any idea what the problem might be in your case. If you find anything, please post your findings...

 

[ericwade381]

yes mine is doing the exact same thing. Not sure really if it is switching to the rear tank or not I do hear it click when the motor is off however my fuel gauge is not reading anything still at the same point where I had filled it up last

 

[IDIoit]

FWIW, i had a problem with both of my tanks in my old 90 F350.
my selector switch was garbage.
i paid the 260ish bucks for a new valve, and all of my problems went away....

 

[ericwade381]

Is the valve a pain to replace etc

 

[IDIoit]

I would be lying if I said no lol
The top likes are the worst, and the diesel fuel all over ya

 

[ericwade381]

I noticed to however my coolant temp gauge is not really working either could this be related

 

[IDIoit]

they never really do lol not related.

 

[franklin2]

If you want to do some testing, you can go down to the valve and unplug it. Find the yellow/white wire, this one goes to the gauge in the dash. Get a piece of wire and attach one end to a known good ground, and with the key in run, touch the grounded wire to the yellow/white wire terminal. The fuel guage should slowly swing to empty or full, depending on what year truck you are working on. Once you take grounded wire off, the gauge should slowly swing back the other way. If it passes this test, the gauge and the wire to the valve are good.

You can plug it back in, look at what tank the valve is supposed to be pulling from, go back to that tank, pull the wiring off the tank, and do the same grounded wire test to see if the gauge still swings back and forth. If it does, then you know the problem is inside the tank.

 

[The Warden]

I noticed to however my coolant temp gauge is not really working either could this be related

Do your oil pressure gauge and volemeter work?

It might be worth your time to pull the instrument cluster and make sure all your connections are happy and corrosion-free, ESPECIALLY if the oil pressure gauge and voltmeter are also dead. But, it might be worth looking at even if they do work.

Did the coolant temp gauge fail at the same time? Like IDIot said, the two circuits don't have anything in common with each other, except at the instrument cluster...so, if there isn't an electrical problem in the cluster, they're not going to be related. But, I believe the cluster's worth looking at...

 

[Zaggnutt]

Stop filling up both tanks and you will figure out which tank you are on.

OLDBULL has the ticket on the replacement. I was working on mine for a couple weeks on and off before I removed it. It's not hard to do. It is helpful to remove the tank guard and straps for better access. There is rubber fuel line on the ends of the metal line where they connect to the selector. If you don't want to get a diesel bath you can use clamps to pinch off the fuel.

I did a long write up on the ball valve switch over. Never have to f@#k with that valve selector again. FYI, when mine was malfunctioning I could still hear it "working" so I wouldn't rely on that test.

 

[IDIoit]

just do what i did, and delete the GD front tank and install a 33 gal rear tank