1994 F150; 4.9L; Automatic. Front gas tank pumps but does not register on gas guage; rear gas tank does NOT pump but does register on gas guage. No electrical hum when I crank and tank switch is on rear tank. Is this a matter of a new sending unit on front tank and pump on rear tank or could there be some other solution to get both tanks to work.
Note: I just bought this truck (114k miles on it) a couple of months ago and was told by the seller that it had set up for several years and not been run. Is it possible that the gas in the tanks have varnished up the components and that they may break free one day or is that just dreaming??
Thanks.

i think your first assumption is correct,possible sending unit faulty or stuck or wiring issue.definitly the pump in the rear if you hear no hum.the rear is the main tank & is the one most comonly used.check,fuses &pump relays & the wiring at the tanks with a test light if you have the juice there with the key on..time to drop the tanks.i had a 95 & rear pump went out approx same amount of miles.i also would alternate the tanks to keep things operating normaly.but some dont.

I prefer to use a volt/ohmmeter for electrical troubleshooting but
that's asking -way- to much I've found.

A good fuel pump will run with a little 9v "transistor radio" battery.

------------------

I messed with a pump one day for at least a couple hours before
I got the varnish loosened up enough to get it to run with a 9v
battery. It's just something a tinkering fool will spend time doing.

That fuel pump can't be trusted, its value is weighed against the
trouble it is to pull a fuel tank, see? Won't hurt to carry it in a
tool box, but that's about it.

Rockauto sells top-quality-fuel pumps and is cheap if the rest of
the sending unit is still good. BTDT it's pretty cool.

Alvin in AZ

lol Alvin,but yes i am in incorperating the volt meter in my trouble shooting. the test light in SOME cases are quicker for me.

BuzzGun79 said:

lol Alvin,but yes i am in incorperating the voltmeter in my troubleshooting.
the test light in SOME cases are quicker for me.

Click to expand...

Sorry, for my sorryassedattitude. :/

I've been preaching analog volt/ohmmeter usage on the internet since the
early 90's (newsgroups, automotive and others) and feel like I've made no
progress. :/

I started the...
"hard knives are better edge holders and easier to resharpen both" idea and
others took up the concept and made a difference. Even the smaller knife
companies started making their knives harder because the idea got wide
spread enough to make a difference in sales. Believe it?

But promoting the use of a "complicated" tool like an analog volt/ohmmeter
hasn't panned-out so good. LOL After they claimed not to know how to
use one (as an excuse) I've offered it a jillion times to teach 'em how right
on the newsgroup or website forum (not just me doing all the teaching,
others jumped-in and seconded the motion) but have had -no- takers. Not
one. Why would they rather stick with the "gambling method" of electrical
troubleshooting? Where'd they get their way of doing it from?

It's like it's divided between two camps, those that already use a meter for
electrical troubleshooting and those that won't even try it.

I've seen a bunch of times where the suggestion of buying and using a fuel
pressure gauge or vacuum gauge (and other even more expensive tools)
was picked up and used, but a cheap analog volt/ohmmeter? Nope.

Got any ideas as to why that is?

Alvin in AZ

electrical, whether in your house or for automobiles, has always been a scary issue to resolve for most people. I think it goes way back to when you had your first electrical shock experience, and for most of use that was when we were little tykes, lol !!