90 f150 , no fuel delivery - Ford Forums

02-04-2006, 18:01

90 F150 .. dual tanks (rear tank leaks , never used)

Truck was run with next to no gas and likely ran dry. Chugged out appx
1000yds from home. Added 3gals but no life. Mechanic frien took a very
fast look and determined that theres no fuel pressure at the engine.

We hear the tank fuel pump run, but someome told me there's TWO?

Anyways, crawling over it tomorrow, whats a good sequence of things to
check to find the problem?

Thanks, Mike

02-05-2006, 07:01

On 4 Feb 2006 17:00:10 -0800, "mpdsville1@yahoo.com"
<mpdsville1@yahoo.com> wrote:

>90 F150 .. dual tanks (rear tank leaks , never used)
>
>Truck was run with next to no gas and likely ran dry. Chugged out appx
>1000yds from home. Added 3gals but no life. Mechanic frien took a very
>fast look and determined that theres no fuel pressure at the engine.
>
>We hear the tank fuel pump run, but someome told me there's TWO?
>
>Anyways, crawling over it tomorrow, whats a good sequence of things to
> check to find the problem?
>
>Thanks, Mike

Your '90 has a pump in each tank. They also had problems
with the tank switching valves getting stuck directing fuel
to the wrong tank. It is quite likely that since you never
used that tank, the valve is now stuck for the one you have
been using. The fuel pump cannot pump thru a closed valve.
The switching valve is where I would look for the problem.

Lugnut

02-05-2006, 17:01

Thanks Lugnut.. I did see posts in this NG related to
the switch valve, but i mentioned the dual tanks and
the fact that one tank is holed on purpose. We NEVER
use the tank switch since one is dead. If the switch valve
is stuck, then i'm betting is stuck in the position its
been in for the last year. I wont ignore its existence but
my gut says its a longshot.

02-05-2006, 18:01

There are actually 3 fuel pumps on the truck. The low pressure one is in the
tank. The one on the frame rail (it's pretty obvious) steps the pressure
up.

The low pressure pumps provide enough pressure to actuate the valve that
switches between tanks. It's made so that it seals in the fuel return line
to the tank that the fuel came out of. It should be obvious why that's
needed. Any leaking from one tank to another is normally not a concern, but
on your truck it might be.

<mpdsville1@yahoo.com> wrote in message
news:1139185867.563493.116130@f14g2000cwb.googlegroups.com...
> Thanks Lugnut.. I did see posts in this NG related to
> the switch valve, but i mentioned the dual tanks and
> the fact that one tank is holed on purpose. We NEVER
> use the tank switch since one is dead. If the switch valve
> is stuck, then i'm betting is stuck in the position its
> been in for the last year. I wont ignore its existence but
> my gut says its a longshot.
>