Dual tank problem
New User
Joined: Dec 2005
Posts: 14
Likes: 0
Ouch! Well I have 2 problems, first my motor starts missing (bad) after it warms up ( i am showing low fuel pres. when it starts missing) and second my fuel tanks will not switch. It shows the front tank when I switch but will not take gas from it. I have replaced the back tank and the filter,and pumps lo and hi. I have replaced all the sensors and the computer box and dist.with its imc that fits on it. it has new wires plugs and cap and rotor, and coil I just can not find the problem ? I am ready to shoot it but then I would have a biger problem LOL Boatbum
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
tuntloan, check the rear tank pump to verify that it is operating. It sounds like it isn't coming on and the high pressure pump keeps drawing from the front.
boatbum, have you checked the computer for codes? Just to make sure, you said you replaced all three fuel pumps and are still having a fuel pressure issue?
boatbum, have you checked the computer for codes? Just to make sure, you said you replaced all three fuel pumps and are still having a fuel pressure issue?
New User
Joined: Dec 2005
Posts: 9
Likes: 0
OK, anyone know where the selector valve is located on the 300 6? I fixed my float issue today in the front tank- guage reads correctly now. Still can't pull fuel from the rear tank. As soon as I switch it, the truck dies. Guage reads about 1/2 tank on the rear.
So is this a rear tank pump issue, or a selector valve issue?
So is this a rear tank pump issue, or a selector valve issue?
New User
Joined: Dec 2005
Posts: 14
Likes: 0
boatbum 4.9 fix
My 4.9 6cyl is fixed, I put in a new (tank frame switching unit from ford $120.00 in) the one that uses pressure from the lo pres. tank pump to switch to the next tank.and it did not help ,so I checked the Dash (3 way)switch to see if it was ok and it was ,next I checked the volts at the switch and found no electrical on the In bound center wire. this would keep the lo pres. pumps from getting the volts to run them. I ran a jumper 12 volt to the dash (3 way)tank switch at the power wire and the problem was gone. YEHAW!! It was a bad power wire at the switch. I still have bad gas in the old tank but the truck now switches tanks and runs great on the new tank. I just need to drain the old tank. Hope this helps Boatbum
New User
Joined: Dec 2005
Posts: 14
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Thanks 4 the help I found a bad (in put) wire at the 3 way toggle gas shift switch on the dash. I got 0 volts after the motor had started missing and o fuel pressure started.
It (after jumping 12 volt to it) it now shifts tanks and you can sit a cup of water on the hood at Idle with no shake. The truck has 90.000 miles on it ! Thanks for the Help Boatbum :-)
It (after jumping 12 volt to it) it now shifts tanks and you can sit a cup of water on the hood at Idle with no shake. The truck has 90.000 miles on it ! Thanks for the Help Boatbum :-)
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Originally Posted by broncoguy75048
Glad to hear your problem is fixed, boatbum. I will check mine out to see if I have the same issue. BTW, I cannot find the selector valve anywhere. Where is it located?
New User
Joined: Dec 2005
Posts: 9
Likes: 0
So what changes the tanks, and if I can't get fuel from the rear tank, is that a pump problem?
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Senior User
Joined: Aug 2004
Posts: 134
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From: Tennessee
Great Illustration above a few post, I have the same one. It is in error though now as I seen the filter it spoke of and took mine apart to discover that there no longer is a replacement filter and the large O ring that gets larger after opening up the darn thing took me all day to find, I found one at a plumbing store. The new valves are no longer servicable is what Morristown Ford Dealer told me.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Originally Posted by broncoguy75048
So what changes the tanks, and if I can't get fuel from the rear tank, is that a pump problem?
You also may have a bad pump, switch to this tank and listen at the tank or filler as someone turns on the key, it should run for one to two seconds.
New User
Joined: Dec 2005
Posts: 10
Likes: 0
check and see if u can here the rear pump come on when u turn the key on. if not than the main pump (just ahead of the supply reservoir) may be drawing from the closest tank (front). it will run just off the main. so maby the pump in the tank is bad.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Originally Posted by 32ford
check and see if u can here the rear pump come on when u turn the key on. if not than the main pump (just ahead of the supply reservoir) may be drawing from the closest tank (front). it will run just off the main. so maby the pump in the tank is bad.
Senior User
Joined: Aug 2004
Posts: 134
Likes: 0
From: Tennessee
I actually pulled the hoses for both tanks and then flipped the switch, both were fine, yet with a full front tank the first week I bought the truck and running out the rear to check fuel mileage if would not pick up tank in front. Had to put a gallon in rear, the it would switch to the rear.
I now run the rear tank only for the weight of the fuel and would really like remove the front tank so I can run the exhaust down both sides and stop them just behind the cab instead of the full exhaust I have now.
I now run the rear tank only for the weight of the fuel and would really like remove the front tank so I can run the exhaust down both sides and stop them just behind the cab instead of the full exhaust I have now.
Last edited by raysvan; Dec 25, 2005 at 07:11 AM.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
Originally Posted by raysvan
I actually pulled the hoses for both tanks and then flipped the switch, both were fine, yet with a full front tank the first week I bought the truck and running out the rear to check fuel mileage if would not pick up tank in front. Had to put a gallon in rear, the it would switch to the rear.
I now run the rear tank only for the weight of the fuel and would really like remove the front tank so I can run the exhaust down both sides and stop them just behind the cab instead of the full exhaust I have now.
I now run the rear tank only for the weight of the fuel and would really like remove the front tank so I can run the exhaust down both sides and stop them just behind the cab instead of the full exhaust I have now.
If you just want the rear tank just do away with selector valve and front tank.