HI! new post and a Fuel Tank Problem
09-21-2014, 04:49 PM
#1
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HI! new post and a Fuel Tank Problem
Hi y'all
this is my first post. thanks in advance for any help!
I have an '86 f150 efi 2wd. it's in decent shape with a tired motor that i'm planning on driving into the ground and putting a fresh crate motor in eventually.
I am a medium level amateur mechanic with most of my experience being on infuriating british cars (i grew up in australia and my dad and i had a collection of Triumphs...). I can definitely change parts out, but my diagnostic abilities leave a bit to be desired.
here's my problem it's in the dual fuel tank set-up. let me try and detail:
1. the vehicle works mostly fine. it starts and runs and drives no problem.
2. the front tank works fine.
3. the selector switch appears to work fine. when i switch it to the rear tank, the gauge shows the tank level apparently correctly.
4. when switching to the rear tank, the vehicle runs fine for a some time then seems to starve of fuel. returning the switch to the front tank works fine.
5. when the vehicle has been running on the front tank and is then parked, after several minutes, fuel starts leaking from the back tank (which is showing empty on the gauge). it appears to be coming from the top of the tank and running down. after some time the leak slows and eventually stops.
6. it seems that with the vehicle running, the leak disappears
7. i have tried operating the vehicle without the fuel cap on the back tank and this appears to have lessened the problem if not fixed it.
any help would be greatly appreciated
this is my first post. thanks in advance for any help!
I have an '86 f150 efi 2wd. it's in decent shape with a tired motor that i'm planning on driving into the ground and putting a fresh crate motor in eventually.
I am a medium level amateur mechanic with most of my experience being on infuriating british cars (i grew up in australia and my dad and i had a collection of Triumphs...). I can definitely change parts out, but my diagnostic abilities leave a bit to be desired.
here's my problem it's in the dual fuel tank set-up. let me try and detail:
1. the vehicle works mostly fine. it starts and runs and drives no problem.
2. the front tank works fine.
3. the selector switch appears to work fine. when i switch it to the rear tank, the gauge shows the tank level apparently correctly.
4. when switching to the rear tank, the vehicle runs fine for a some time then seems to starve of fuel. returning the switch to the front tank works fine.
5. when the vehicle has been running on the front tank and is then parked, after several minutes, fuel starts leaking from the back tank (which is showing empty on the gauge). it appears to be coming from the top of the tank and running down. after some time the leak slows and eventually stops.
6. it seems that with the vehicle running, the leak disappears
7. i have tried operating the vehicle without the fuel cap on the back tank and this appears to have lessened the problem if not fixed it.
any help would be greatly appreciated
09-26-2014, 09:52 AM
#4
Senior Member
Just drop the rear tank and take a look?
I changed my rear tank without any help... removed all the under trunk spare tire mounting stuff (has a spare in the bed) as I replaced the old
tank with a 39 gallon rear tank. Just used a flat board and floor jack as my "helper"... when tank is dropped down (easy if empty) you get to the wiring and lines on the top.
Of course my slightly older truck does not have fuel injection... but it appears to be a similar amount of work....
Side tank is even easier to remove/replace.
tank with a 39 gallon rear tank. Just used a flat board and floor jack as my "helper"... when tank is dropped down (easy if empty) you get to the wiring and lines on the top.
Of course my slightly older truck does not have fuel injection... but it appears to be a similar amount of work....
Side tank is even easier to remove/replace.
Last edited by Roger Mabry; 09-26-2014 at 09:54 AM.
12-02-2014, 08:44 PM
#5
Some times on the older trucks the rubber in the fuel lines is so old and weak the rubber line may collapse and starve your motor of fuel.May be a bad fuel selector valve on the drivers side rail?. Sounds like your having to drop the tank and have a close look. Good luck.