'93 F150 dual tanks not working
08-30-2011, 10:16 AM
#1
Junior Member
Thread Starter
Join Date: Aug 2011
Location: Oklahoma
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
'93 F150 dual tanks not working
I have a '93 F150 5.8L with dual tanks. When I flip the switch it just dies and wont start up until I switch it back to the rear tank. The fuel gauge will change when I flip the switch so I know its working but I don't know what is not working. Any ideas?
08-30-2011, 11:22 AM
#3
Junior Member
Thread Starter
Join Date: Aug 2011
Location: Oklahoma
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
Alright Thanks Is there any way to double check the fuel pump is bad before I replace it? I am a college student on limited funds so I just want to be sure before I replace it.
08-30-2011, 11:38 AM
#4
broke white boy
you can with the truck off switch to the front tank. then with the door open and head leaning out. or you under the truck with a friend at the key turn the key on BUT dont start the truck. you should hear the pump kick on and run for about 3 seconds.
that is the free check.
if the pump does not kick on turn off the key and hit the flat spot on the tank a few times pretty good. then try again.
but my experiance with these trucks 9 out of 10 times the pumps are junk and you have to replace them.
that is the free check.
if the pump does not kick on turn off the key and hit the flat spot on the tank a few times pretty good. then try again.
but my experiance with these trucks 9 out of 10 times the pumps are junk and you have to replace them.
08-30-2011, 12:45 PM
#6
Senior Member
Join Date: Jul 2011
Location: USA
Posts: 628
Likes: 0
Received 0 Likes
on
0 Posts
Both fuel pumps are powered by the fuel pump relay but ensure there is voltage at the fuel pump connector anyway, before replacing the fuel pump. There is a 95% chance it is the fuel pump going out on those systems but you can never be too careful, rats get hungry too. 
Be lucky the check valve hasn't went bad where one pump pumps all the fuel into the other tank and vice versa, that happened to my dad's truck. If I had to drop the fuel tank again, I would probably cut out a access panel with oxy/acy torch so it wouldn't have to be dropped ever again. That is, when every last drop of fuel has been eradicated completely, first!
Be lucky the check valve hasn't went bad where one pump pumps all the fuel into the other tank and vice versa, that happened to my dad's truck. If I had to drop the fuel tank again, I would probably cut out a access panel with oxy/acy torch so it wouldn't have to be dropped ever again. That is, when every last drop of fuel has been eradicated completely, first!
Last edited by bluecar5556; 08-30-2011 at 06:32 PM.
08-30-2011, 12:49 PM
#7
Old Bastard
Originally Posted by bluecar5556
Both fuel pumps are powered by the fuel pump relay but ensure there is voltage at the connector anyway, before replacing the fuel pump. There is a 95% chance it is the fuel pump(s) going out on those systems but you can never be too careful, rats get hungry too.
Be lucky the check valve hasn't went bad where one pump pumps all the fuel into the other tank and vice versa, that happened to my dad's truck.
Be lucky the check valve hasn't went bad where one pump pumps all the fuel into the other tank and vice versa, that happened to my dad's truck.
Trending Topics
08-30-2011, 01:25 PM
#8
Senior Member
Join Date: Jul 2011
Location: USA
Posts: 628
Likes: 0
Received 0 Likes
on
0 Posts
Last edited by bluecar5556; 08-30-2011 at 01:38 PM.
08-30-2011, 02:23 PM
#9
Originally Posted by kc0rey
The fact that he has a working fuel gauge on that tank, means he has power at that pump.
08-30-2011, 02:37 PM
#10
Senior Member
Join Date: Jul 2011
Location: USA
Posts: 628
Likes: 0
Received 0 Likes
on
0 Posts
The fuel tank selector switch is (2) DPDT switches linked together, one DPDT switches the fuel gauge sending unit and the other switches the fuel pumps, as illustrated above. Just because the fuel gauge switch from one rheostat to the other, does not mean the other fuel pump switch isn't worn or faulty that terminate at the fuel pumps. Makes sense, those contacts have to switch a several amp payload (fuel pump) vs. a very small current passing through a rheostat and energizing the windings inside the fuel gauge to move a very light armature.
This is why I am stressing to test the voltage at the fuel pump before replacing it. The fuel tank selector switch could have a bad contact, here.
This is why I am stressing to test the voltage at the fuel pump before replacing it. The fuel tank selector switch could have a bad contact, here.
Last edited by bluecar5556; 08-30-2011 at 02:46 PM.