Dual Tank Problems
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Dual Tank Problems
Howdy FTE friends. I have a 1990 F150 Custom, L6, with dual tanks.
The front tank operates normally but doesn't register on the dashboard, which is likely a faulty fuel tank sending unit. When I switch over to the rear tank it sputters out after 2-3 seconds, which is likely a bad fuel pump. The rear tank does register on the dash however.
While troubleshooting today I switched to the rear tank and it died out as expected. Upon switching back to the front pump though I can't get the engine fire up. How do I get her to pull from the front tank again? Thanks gurus.
The front tank operates normally but doesn't register on the dashboard, which is likely a faulty fuel tank sending unit. When I switch over to the rear tank it sputters out after 2-3 seconds, which is likely a bad fuel pump. The rear tank does register on the dash however.
While troubleshooting today I switched to the rear tank and it died out as expected. Upon switching back to the front pump though I can't get the engine fire up. How do I get her to pull from the front tank again? Thanks gurus.
Posting Guru
Joined: Nov 2009
Posts: 1,187
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From: Lynnwood Wa.
Welcome to be he forums. Try switching the tank selector back and forth a few times and try again. Wait until tomorrow hopefully subford will chime in I do not remember how to do the test right off. Search for fuel pump self test.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Your right about a bad sender in the front tank and maybe a bad fuel pump in the back tank.
If the front pump is running a for one second when you turn the key to run but will not start but will try to start if you spray starting fluid in the throttle body then I would say you need to replace the rear pump. You would then have an open valve in the rear pump.
But if you can hear the rear pump run for one second when you turn the key to run then your whole problem may be you have a bad front pump or more to the point bad valve in the front FDM.
As Crewcabber said above if the pumps are not running at all you may have a bad selector switch on the dash.
In other words we need more information from the tests that you may run. As in fuel pressure checks, do the pumps run, does it start on starting fluid, do you have a loading test light to check for power and so on.
If the front pump is running a for one second when you turn the key to run but will not start but will try to start if you spray starting fluid in the throttle body then I would say you need to replace the rear pump. You would then have an open valve in the rear pump.
But if you can hear the rear pump run for one second when you turn the key to run then your whole problem may be you have a bad front pump or more to the point bad valve in the front FDM.
As Crewcabber said above if the pumps are not running at all you may have a bad selector switch on the dash.
In other words we need more information from the tests that you may run. As in fuel pressure checks, do the pumps run, does it start on starting fluid, do you have a loading test light to check for power and so on.
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It will run for a few seconds on starter fluid, but I am not hearing either pump kick in when I turn the key, so I am going to replace the selector switch and see if that takes care of the issue. If that does not work I will precede with some other tests.
I am thinking the switch might be the culprit as I drove it normally for about 45 minutes just prior to trying to switch to the rear tank, so I am fairly confident that the front tank and pump are working correctly. But I guess crazier things have happened. I'll post the success or failure of the switch when I get it in a few days. Thanks.
I am thinking the switch might be the culprit as I drove it normally for about 45 minutes just prior to trying to switch to the rear tank, so I am fairly confident that the front tank and pump are working correctly. But I guess crazier things have happened. I'll post the success or failure of the switch when I get it in a few days. Thanks.
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I replaced the original switch with a new one directly from Ford for $45 and it fired up! As a bonus, I switched to the rear tank and the fuel pump kicked in flawlessly. Two birds with one stone! Thanks for the help Subford and Crewcabber.
-Part number E7TZ9A050A (on the actual switch it reflects E7TZ9A050AC)
-My 1990 Custom was manufactured in 89' which made a difference in the part
-Part number E7TZ9A050A (on the actual switch it reflects E7TZ9A050AC)
-My 1990 Custom was manufactured in 89' which made a difference in the part
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