Fordnatics List Archive

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Clifton Koch)

Welcome to part 2 of my fuel delivery upgrades to my car. Part 1 was
a MAF/30# injector conversion, and this will cover a larger fuel pump
installation.

I had nabbed a write up that someone else posted once that was quite
good on this subject, but I did have some slightly different
experiences, so I decided to write this.

The car is an '88 Mustang GT which had just been converted to MAF and
is using 30# injectors. Next up is installing a 155lph fuel pump.

I had wanted to check the fuel pressure before and after the upgrade,
but found I didn't have a gauge that the pin would go deep enough in
the schrader valve to open it and I wanted to get this done, so I blew
it off.

First, I drove the car around until it was on fumes, or at least I
thought it was. Mustangs gauges suck, but I repeat myself, and I can
drive for a couple of days with my fuel gauge sitting on E. If I fill
the tank when the fuel light first comes on, I put in about 10 gallons
(it's supposed to be a 15 gallon tank, right?), but I digress. I had
meant to toss a gas can in the car when it was really getting low, but
I forgot. I made it home, and the tank still had about a gallon in
it. I'm not sure how much of that gallon could have actually been
pulled in by the pump.

The first order of business is to disconnect all of the lines going
to the tank. These consist of a fuel output, a fuel return, a vent
line, and an electrical connector. All of the fuel lines are towards
the front of the vehical. To remove the flexible fuel outlet line from
the hard line going to the engine, you need to remove a small clip
which slides into the connector and keeps the line from being blown off
from the fuel pressure. This is very easy to do, and the line slides
right off. Be careful, as some gas may leak out when you do this (it
did on mine). Oh, yes, you should relieve any fuel pressure from the
system at the schrader valve first (which I had done). The connector
on the return line is a bit tougher. It requires that you push in on
tabs on both sides of the connector with a fair amount of force while
pulling the connector off at the same time. A pair of right angle
needle nose pliers worked well for me, but it took a bit of finesse.
The vent line just pulls off.

There is a single electrical connector towards the back of the tank
which needs to be disconnected. This Ys off on the tank to go to the
fuel pump and fuel level sender.

Now you just have to loosen the straps and the tank will come free,
but be *careful*. The other write up said his tank stayed in place
when the straps were loosened. Mine did not. It started lowering
immediately as I started loosening the straps. You should support the
tank when loosening the straps. I used a floor jack. Once the straps
are loose, the only thing left connecting the tank is the filler tube.
It goes into the upper side of the tank through a rubber grommet.
Things will go a bit easier if you remove the straps to get them out of
the way, which are held in place by a free floating pin on the one
side. You can get the pin out by pushing through the small hole on the
side of the pin housing with a small screwdriver and pushing it out the
other side. I didn't attempt to remove the filler tube, as it didn't
look like it'd be possible to do with the tank in place. If it is
possible, it'd probably make this job a fair amount easier. I never
removed the plastic lower cover from the tank through any of this. I
just moved them as a unit.

Anyway, I lifted up on the tank and kicked the jack out of the way.
A little shimmying back and forth got the tank to slide off of the
filler tube. And suddenly I was holding a tank too close to the middle
with gasoline racing towards the outer edge. It of course picked the
edge that had the now gaping open filler hole. A bit spilled out, but
not too bad. Actually it was worse than that. Apparently I got too
much weight on or twisted the tank too much when disengaging it from
the filler tube grommet. The rubber grommet has a thick conical outer
surface with a very thin inner sealing area. The inner sealing area
ripped, which kept me from getting the job finished in one evening.
Either be really careful when pulling the tank off or plan on replacing
this gasket. If the filler tube can be removed with the tank in place,
this shouldn't be a problem.

Once the tank is out, it's easy to work on. The fuel pump assembly
is loosened by turning a locking ring on the top of the tank. It
takes a bit of contorting and twisting of the fuel pump assembly to get
it out. It helps if you look in through the filler hole so you can see
what the assembly looks like. There's a small rubber nipple on the
fuel return line that appears to direct gas over the fuel pump for
cooling that's easy to knock off when removing the assembly, so watch
for that. I bought the fuel pump only, so the old pump had to be
removed from the assembly, the electrical connections removed, and the
crimp on clamp used to connect the high pressure fuel line cut off.
Remember to re-clamp the fuel outlet hose when reassembling. I almost
didn't. In order to get the old fuel pump out of the assembly, the
filter needs to be removed, but note the direction it's attached. The
assembly has a sort of U shaped piece of metal that the pump sits down
it, which is connected to the upper part of the assembly by 4 hex
screws. Removing these screws and opening up the U allows the pump to
come out.

The new pump was exactly the same dimensions as the old one. The new
fuel filter was a bit different, though. The old filter was a sort
of flat rubber screen. The new one looked sorta like a stiffened nylon
tube. The filter is a press fit, and look at the direction that the
original filter fit on the original pump to get the orientation of the
filter correct. Replace the electrical wires, and put a clamp on the
short fuel line going from the pump to the hard line on the assembly.

Now just snake the assembly back into the tank. Again, it's best to
look though the filler hole so you can see what you're doing. Also
watch that the rubber nipple stays in place when putting the assembly
back in. Then just turn the locking ring back into place, and you're
done.

To get the tank back on the car, I again used the floor jack. Be
really careful if you use a floor jack, as it wouldn't be hard to
crush the tank. I was watching the tank bottom very carefully as I
lifted it. I balanced the tank on the jack and got it as high as it
would go (it won't be positioned right for the floor pan hump until the
filler tube is engaged), lifted the one side and engaged the filler
tube. I put a bit of WD-40 on the tube as a lubricant, and worked the
filler tube into the rubber grommet. I then had to move the tank
around a bit until it fit snuggly into the rear floor pan, and
re-attached the straps. Then I reconnected the fuel hoses, put the
outlet line retainer back in, and reconnected the power connector.
After adding some gas, the car started right up.

The new pump might be a bit louder than the old one, but it's also a
lower pitch, so I think it's a little less noticeable than the old
one. So far I haven't had any problems, and the fuel delivery system
of my car should be ready to supply plenty of fuel for a supercharger
without doing anything silly like cutting off fuel return fuel lines or
some such nonsense. I never cared for that practice because the fuel
in the return line is partially responsible for cooling the fuel pump.

Be sure to join me for the next episode: The supercharger <evil
grin>. Coming to a mail list near you soon (within the next few
weeks, I hope).

Cliff

- -----------------------------------------------------------------------------
Cliff Koch
Motorola Cellular Infrastructure Division
(email redacted)