my question is this ive got dual tanks on the truck and the selector under the radio ive owned the truck about a month and im afraid to switch it to the front tank being that its on the rear

also my tach doesnt work (injector pump houseing sensor right?)
fuel guages dont work either
im only getting power with key on engine cold to the shut down solenoid on the inj pump (temp switch under alternator right?)

and as well the truck will only start with a sniff of ether being that the glow plugs and relay are non op i did the test light test on a few glow plugs and none lit up so

but when i jump the solenoid i get 12v to each glow plug terminal on the harness

ive switched the tanks with it running for a quick second because i dont want to run the lines dry if the front tank doesnt work so what are my options here switch the tank and see what happens how will i know it switched?

i know i jumped off topic a few times but like i said im new to a 6.9 diesel not cars in general i can do just about anything and have a general idea how they work plus i got a book but some things are better answered by the pros ya know

again i appreciate any replys that i get i havent posted till now because the search option on this site works wonderful and has gotten me this far with the truck

Joe DiMassi

 

I'd put a few gallons of fuel in the front tank and try the switch - you should also see the fuel gauge drop some when you do switch tanks. The only way to know for sure it did actually start sucking from the front tank is to drive the truck and observe the fuel gauge, if it's going lower then all is good. Now to actually fixthe fuel gauges, drop the tanks and see if the floats haven't filled with fuel and sunk to the bottom - one of mine was bad like that, so I took the brass float out and put a small bottle of pills in its place (sans the pills of course), it makes for a good float and won't fill with fuel and sink cause it can't develop pinholes in the solder that ain't there to begin with.

Glowplugs - your controller probably failed and friend the plugs - install the manual switch many others here have in their trucks, and replace glowplugs as needed (you'll have to pull them to verify they're good or shot).

 

yea fuel guages dont move at all not even a flicker and both tanks were filled when i picked the truck up i verified that by filling them myself back tank took $8 front took about $10 im been just using the back tank (thats whats switched to but havent filled tank to see if its been using it) how big are the tanks on that truck front tank (34 gal) rear tank (19)?

 

Both tanks were 19 from the factory. Have you checked the fuses? There is one that runs the fuel gagues and fuel slector valve. You should hear a faint zipping sound from the fs valve when the switch is moved from one tank to the other.

 

Yeah, with ignition on but the engine off and with the door closed (so the chime under the dash stays quite) if you stick your head out the window you can hear the FSV buzzing when you switch from tank to tank. Or have someone work the switch for you, while you have you're under the truck to hear the thing better.

Your gauge not registering any fuel could be either sending units, or floats, or even connections on top of tanks - connectors are easiest to clean, then for the floats and senders you'll have to drop the tanks. And then I already told you the trick with the medicine bottle as a float, if you don't wanna spend the $10-15 for a factory Ford one...

 

thanks for the replys no droppijn tanks luckily its a rollback baed i can get at both ill let yous know how i make out with the guages

 

Oh yes, I forgot that you can lift the bed and get to the senders on top of the tanks - must be nice! lol

 

it doesnt look like they were ever touched i say that because alot of times you will see aftermarket stickers such as air tex etc. terminals look clean i am gonna pop the sending units out when i get the load off the bed hopefully tomorrow and then wit an assistant ill move the float and see i mean as soon as i hold it ill know if it has fuel in the float had same prblem with the trucks at work and it was the 8 dollar brass float

 

got to flip the tank switch back and forth with an assistant with just the key on and i did not hear anything no buzzing or nothing? is there fuses to be checked? i was looking at the switcher on the frame didnt hear anything coming from it or doing anything..... still havent got the sending units off yet been really humid lately and its hard getting around after acl reconstruction

 

Yes there is a fuse that is for the fuel gagues and the selector valve, located in the cab fuse box. I don't recall which one it is though.

 

My 90 won't switch from the front to the back tank and the gauges are mesed up on both.
I understand how to fix the sending units but I am going to watch and see what advice you get about the Front/rear tank switch.

 

i think i forgot to include something im still unsure which tank is pullin fuel i filled both tanks when i bought the truck and have only put 125 miles on the truck so i havent topped tanks off again to see which tank is pullin fuel

when i do ill get to update yas as well....hopin my inlaw gets the welder and mc trailer off the back then i can hobble with the sending units and such i dont mean to drag this thread out but im just getting my ducks in a row and will update as im playin with it thanks again guys

 

I looked this morning, and the fuse for the fuel sel. valve is the red 10 amp fuse located under the flasher. It is in the second row from the left side 2 fuses down from the round flasher. Same position in both the 85 and the 90. If this fuse is blown it will affect the fuel gagues and the tank select valve. Hope this helps.

 

well i went and checked the fuses and there all good....... fuse box got quite a few black burn marks on it and quite a few 30 amp fuses haha wish i wouldnt have looked and its not hooked to anything just hangin kinda chillen by the wires ill keep ya posted guys thanks for all the help this far

 

Along the same line as jdimassi, I have an 86 f250 w/6.9. The fuel gauge registers only on tank. I thought it might have been the valve but still dont know. The switch under the radio seems to work as the power coming to the valve itself switches as i move the switch in the cab. I read the part here about the floats getting full of fuel. Ant ideas as to really pinpoint the problem I am having without pulling the tank? could the fuel gauge it self not be wired right. I know its just a lot of circuitry behind the gauges so does the signal from the tanks separate somewhere prior to the gauge. Thanks for any help.