78 f-250 problems
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Senior User
Joined: Oct 2001
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78 f-250 problems
my fuel tank switch doesn't seem to work properly.just bought the truck on sat.noticed when i went to check the reserve tank that it went to zero even though i filled it.does this switch actually switch the tanks or is it a indicator of some kind.i'm afraid to run out of gas on the regular one and not have a reserve.or maybe it doesn't matter and it goes to the other tank by itself.i don't know diddly!!! any info someone???.......CARS!!!!arrrr!!! ...another problem for me is the trans,it doesn't shift automatically like it should.i have to let up on the gas and it does fine.yes,it's a automatic.what part do i need and is it difficult to install.would it be a power valve??? do i have to have the tranny off?...just starting learn.have a toyota corolla and just about nothing goes wrong with that.just really frustrating.any input/.... by the way,thank you guys for answering my other question the other day.joe
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Joined: Feb 2000
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From: Palm Bay, Florida
78 f-250 problems
I had a simmiliar problem with my '78 F150 a few years back, I found it to be the tank selector valve which is located on the drivers side just inside the frame about 1/2 way back it has 1 wire going to it, and the fuel lines of course, it is set up for 3/8" lines, but an aftermarket valve in 3/8" is(was)hard to find so I used a common 5/16" & snugged the NEW 3/8" hose down onto it, I'm not saying to "jerry-rig" your truck, may be the 3/8" valves are available now, I know the factory ones are high dollar.
On your transmission: Change the filter&pan gasket, (they come as a kit)clean the inside of the pan well, install a NEW modulator valve, its the bell shapped thing outside the trans case in the passingers side, check ALL of your vacuum lines on your engine for cracks/leaks, replace as nessessary, and check/replace the short rubber vacuum lines at both ends of the metal line running to the modulator, this should inprove your shifts. Rick
On your transmission: Change the filter&pan gasket, (they come as a kit)clean the inside of the pan well, install a NEW modulator valve, its the bell shapped thing outside the trans case in the passingers side, check ALL of your vacuum lines on your engine for cracks/leaks, replace as nessessary, and check/replace the short rubber vacuum lines at both ends of the metal line running to the modulator, this should inprove your shifts. Rick
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78 f-250 problems
[updated:LAST EDITED ON 14-Dec-01 AT 00:54 AM (EST)]If the sending unit isn't functioning properly inside the reserve tank-the fuel gauge will not work or give erronous readings.....the swing arm inside the tank is hooked to a variable resistor and as the fuel level inside the tank rises and falls the resistance will increase or decrease which in turn varies the voltage being sent to the fuel gauge---which in turn is hooked to your billfold and will only Decrease the amount of money you have to buy More parts to fixup your truck!!!!!!!!!!!!!fd------I should add that the switch that switches from one tank to the other also switches the functioning of the fuel gauge to that tank as well-----I don't know what year ford incorporated this system into their trucks---on older trucks the fuel switch---just switched the flow of fuel Only---fd
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78 f-250 problems
If you run out of fuel to carb after you switch the tank(with both tanks having fuel in them)it is faulty fuel valve.
If you still have fuel getting to the carb after switching but,the gauge bottoms out to empty,then it is a Faulty Fuel Sending Unit.
Usually,if the sending uunit fails the Valve will Still switch tanks.
Try replacing the switch first from a donor truck.
They are know to go bad.
Dennis
It's Almost Time Everyone.
https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=314&.jpg
78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles
If you still have fuel getting to the carb after switching but,the gauge bottoms out to empty,then it is a Faulty Fuel Sending Unit.
Usually,if the sending uunit fails the Valve will Still switch tanks.
Try replacing the switch first from a donor truck.
They are know to go bad.
Dennis
It's Almost Time Everyone.
https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=314&.jpg
78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles
78 f-250 problems
