Dual Tank blues....

IDIDieselJohn · Jan 5, 2012

Howdy guys!

I got an annoying problem. I have no idea if my dual tank switch actually works in my van.

I went for a ride around the block, and it ran out of fuel at the other end of the block, fuel gauge was right on 1/2 mark.

Had to tow the damn thing with a 2wd F150...yeah that was interesting in snow covered roads!

Alright, so heres what I know...

I drove 2 hours to go get this van, and drove the van back that 2 hour trip, all highway. When we left where I bought it, BOTH tanks were at 1/2. originally the REAR tank was selected, but I switched to the FRONT tank to drive home.

All the way home, the gauge never moved! Once home I'm like ***? I then selected the REAR tank again, and now the Rear tank was damn near empty!

So is it possible that the selector valve is stuck on the rear tank.....but still reads for witch ever one is selected?

And heres a twist to all this, the gas gauge is ALWAYS live in this van, even with key off, turn signals, wipers, radio, everything works without turning the key on, so obviously someone has played with the wires under the dash..... could this be related? I have to keep the batteries disconnected to keep them from draining.

A little help would be very appreciated, never messed around with Dual tank problems before, I searched, but didn't find a similar problem to mine that has a clear answer.

(I did it get it running again by filling up the half empty fuel filter, and cracking open some lines, and dumped a 5 gal jerry can in the FRONT tank...)

bike-maker · Jan 5, 2012

Thats what mine did when it gave up, except the gauge read off of the rear tank, pulled from the front tank, and returned into the rear tank, overflowing the tank and dumping diesel everywhere.
i permanently fixed the problem by switching to manual valves.

GreenDiesel · Jan 5, 2012

Not sure if this will be any help but, I once had a problem of my selector valve returning fuel to the wrong tank.

I drove around for 150 miles and my front tank only showed I had used 1/4 tank. Thought I was getting 40MPG lol, until I switched to the rear and it was almost empty :O

It was showing the level of the front tank, but I think it was drawing from the rear and returning to the front...?? Who knows..

I poured some ATF in both tanks and that seemed to clear it up.. for now

Perhaps something was stuck in the selector valve

IDIDieselJohn · Jan 5, 2012

bike-maker said:
Thats what mine did when it gave up, except the gauge read off of the rear tank, pulled from the front tank, and returned into the rear tank, overflowing the tank and dumping diesel everywhere.
i permanently fixed the problem by switching to manual valves.

How do you convert to manual valves?? :dunno

bike-maker · Jan 5, 2012

I wish i would have taken more pics when i did it, lots of people have asked about it. Ill post up some of the pics i have when i get home later today.

itsacrazyasian · Jan 5, 2012

IDIDieselJohn said:
How do you convert to manual valves??

i used two 3 port marine click stop valves. mine are on the transmission tunnel. Got mine from west marine.

NTOLERANCE · Jan 5, 2012

I had a similiar thing, the fuse blew.

91idi · Jan 5, 2012

I had a wood chip causing mine tsv to not work. Took it off and spayed wd40 in it and switched back and forth till I saw something fall out (stupid wood chip)

OLDBULL8 · Jan 6, 2012

So is it possible that the selector valve is stuck on the rear tank.....but still reads for witch ever one is selected?

And heres a twist to all this, the gas gauge is ALWAYS live in this van, even with key off, turn signals, wipers, radio, everything works without turning the key on, so obviously someone has played with the wires under the dash..... could this be related? I have to keep the batteries disconnected to keep them from draining.

A little help would be very appreciated, never messed around with Dual tank problems before, I searched, but didn't find a similar problem to mine that has a clear answer.

Not to difficult to remove and clean the FSV. You just have to clamp off the lines (3/8") from the tanks or you'll drain them and fuel will run down your arm.
Go here for the FSV and wiring diagram. The selector may be stuck part way. Wiring is generic, but close to any truck.
http://community.webshots.com/user/oldbull8?

Click to expand...

bike-maker · Jan 6, 2012

I got some 3-way ball valves from McMaster-Carr and installed them on the floor of the cab just to the left of the drivers seat. I extended the fuel lines from where the FSV was to the new ball valves.
You can wire a switch in place of the FSV and use the switch to select which fuel tank is read by the fuel gauge.

CaptTom · Jan 6, 2012

OLDBULL8 said:
So is it possible that the selector valve is stuck on the rear tank.....but still reads for witch ever one is selected?

And heres a twist to all this, the gas gauge is ALWAYS live in this van, even with key off, turn signals, wipers, radio, everything works without turning the key on, so obviously someone has played with the wires under the dash..... could this be related? I have to keep the batteries disconnected to keep them from draining.

A little help would be very appreciated, never messed around with Dual tank problems before, I searched, but didn't find a similar problem to mine that has a clear answer.

Not to difficult to remove and clean the FSV. You just have to clamp off the lines (3/8") from the tanks or you'll drain them and fuel will run down your arm.
Go here for the FSV and wiring diagram. The selector may be stuck part way. Wiring is generic, but close to any truck.
http://community.webshots.com/user/oldbull8?

Click to expand...

Thanks for the ref OB8. Those detailed pics are great. The ports are obviously 3/8 (Sup) and 5/16(Ret) in the photo's too. The side with only 2 ports is obviously engine side and tank side has the 4 bibs. Very useful pre-work reference.

I was going to put in my Purolater this weekend, the photo's helped out a lot. I have all the marine grade A1 fuel hose, fittings, clamps and pump. Now just need to fab up the mount----I'm going inside rail with stone guard. I'd like to mount it as high as possible to avoid stones and sheering it off a speed bump. Also, inside rail less obvious to passer-by's who may have and eye out to drain my system for their own use by removing the bowl.

Had to ix-nay on the street elbows though. All the ones I found in 1/8" bronze had a restricted hole, far smaller than the standard 90's. I didn't want to drill them up for better flow either. Never know if casting is bad, risk thin walling them. Going from a 1/8" port to 3/8" line freaks me out a little, if it wasn't for the rated flow above the mechanical, I would've stayed mechanical.... although fuel in oil freaks me out more.

Sorry about the hi-jack

Click to expand...

IDIDieselJohn · Jan 7, 2012

Tom, don't worry about the hi-jack, I catch my self doing it to.

Alrighty, went exploring under my **** office today,

The FSV works great, and only works with the key ON. While my dad was switching between tanks, I was under listening to it, and can clearly hear a ZIIIP sound as soon as you flick the switch.

I also tryed turning key off, while it was on front tank, selected rear tank, nothing happened, turn key back ON, and it ZIIPED to rear tank as soon as the key went on.

So that works.

Found a fuse box diagram also, and all fuses work, including the one for the tank selec.

Now, I did notice the 2 hoses closest to the frame on the valve have been tooken off at some point as they have pretty fresh looking gear clamps.

Heres what I don't get, the 2 TOP hoses go the front tank, and the 2 BOTTOM ones go the rear tank (witch looks new). But the 2 hoses that look like they've been removed recently, are 1 for each tank.

Could the hoses be messed up?

Heres a pic, again, 2 TOP hoses go to rear tank, 2 BOTTOM hoses facing rear, go to front tank.

Does this look ok?

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Dual Tank blues....

IDIDieselJohn

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bike-maker

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GreenDiesel

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IDIDieselJohn

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bike-maker

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itsacrazyasian

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NTOLERANCE

I'm the cotton swab

91idi

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OLDBULL8

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bike-maker

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CaptTom

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IDIDieselJohn

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