Changing fuel pump any advice?
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You'll find a link about changing the fuel pump in the TTA FAQ List near the top of this forum 
Also, there is a page on GNTTYPE.org on this subject if you can find it....
Good Luck
Also, there is a page on GNTTYPE.org on this subject if you can find it....
Good Luck
tim87tr
Obsession or Digression?
- Joined
- Sep 19, 2001
- Messages
- 1,295
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I did it last year, it took me a weekend, or a total of 20 hours (I am a newbie on mechanical things...)
I followed this description, you cant go wrong if you follow this:
Note: Disconnect the battery in the engine compartment to avoid any
possible
sparks as you're going to be messing around with gasoline...good idea to
have fire extinguisher for backup safety.
1. First thing is to get two jack stands and jack up the rear of the car
as
high as you can...I had my jack stands on the second hole from the
bottom or
as high as my floor jack would raise the car. Put the jack stands under
the
left and right side rear frame rails.
2. Open the gas tank filler door and remove the 3 screws that hold the
white
door to the interior black plastic cup...remove the white door. Unscrew
the
3 screws that hold the black plastic interior cup into the rear quarter
panel. You should now have nothing around the gas tank filler neck and
be
able to see down the filler neck to the gas tank.
3. Remove both rear tires/wheels.
4. Next step is to drop down the muffler from it's mounts on the body.
Driver side has one bolt through a hanging rubber bracket...passenger
side
requires 2 bolts be removed from the mounting bracket that bolts into
the
frame. Carefully lower down the muffler....don't let it fall on you! I
also
unbolted the exhaust pipe from the back of the catalytic (removed two
nuts
holding exhaust pipe flange to catalytic). This is important as it
makes it
a lot easier later if you can move your exhaust pipe/muffler out of the
way
and you won't be able to if it's still bolted to the catalytic.
5. With the muffler hanging down, you can now access the small hex
screws
that hold the thin metal exhaust shields below the gas tank and above
the
rear axle. Remove all these screws and the two separate thin metal
shield
plates from the car.
6. Slide a floor jack under the center of the rear axle and slightly
support
the weight of the rear axle on the jack.
7. There is a flat bar that goes across the rear of the car...it's
bolted to
the driver's side frame with 3 bolts and the other end is attached to
the
passenger side with one long bolt. Remove these bolts and remove the
bar.
This bar is what some of the small hex screws from the exhaust metal
shields
screwed into.
8. The remaining horizontal bar that bolts to the frame on the driver
side
and to the axle housing on the passenger side should also be removed at
this
point.
9. Unscrew the main rear metal brake line from the flexible hose that
goes
to the distribution block on the axle. Remove the flexible brake line
retaining clip that holds it to the metal frame bracket...the flexible
brake
hose should be free from the frame as it could be damaged when you lower
the
axle housing later if it was still attached to the driver side frame
bracket. Some people have said you don't have to un-do the brake
line...but
I recommend you un-hook it and just bleed your rear brakes later to
avoid
damaging any brake lines.
10. Jack up the rear axle slightly to take pressure off the stabilizer
bar....unscrew the 9/16 long bolts that hold the rear stabilizer bar to
the
frame brackets on both the driver and passenger sides. The bolts can be
hard to get off as they rust pretty badly....if you break it,
replacement
poly bushings and bolts are still available/in stock at dealers as they
fit
a lot of years.
11. With stabilizer bar ends disconnected, remove the lower retaining
nuts
on the driver and passenger rear shocks. Carefully slide the shocks out
of
the rear axle mounting holes. Be sure the axle is supported on the
floor
jack as the axle can swing down now as the shocks no longer hold it up.
12. Slowly lower the floor jack to get the tension off the coil
springs...
let the axle drop as far as it can go...don't get nervous when the rear
coil
springs fall out....they are easy to reinstall and just sit on the axle
pads.
13. Find the 4 metal fuel lines by the driver side frame. Two lines
have
screw clamps, one line has a tension clamp and the main pressure line
has to
be unscrewed with wrenches. Remove only the lower clamps on the three
lines
and slowly unscrew the main pressure line to relieve any pressure in the
line. Slide the lines upward off the metal lines coming along the
frame...all fuel lines should be above/disconnected from the metal frame
lines.
14. Slide your exhaust system (muffler/pipe) as far to the passenger
side of
the car as possible above the rear passenger brake rotor assembly...this
will help provide clearance as the tank is removed by sliding down and
towards the passenger side wheel. Unscrew/remove the gas filler cap.
15. At this point, you're ready to unscrew the two long bolts that hold
the
gas tank retaining straps to the underside of the car. I made a point
to
drive my car to almost an empty gas tank to keep the weight of the gas
tank
as low as possible as I was doing the disassembly myself and it's no fun
when you have a heavy/filled gas tank. The tank will be heavy and hard
to
handle if you have a lot of gas in it!!!
16. Remove the two retaining bolts and let the gas tank straps swing
down...be sure and not bend the straps as it makes them much harder to
reinstall...support the gas tank with your hands and slowly slide it
towards
the passenger side of the car. You will need to slide it as far to the
passenger side as you can and then downward to clear a metal lip on the
frame in the gas neck filler area. Don't force anything and don't bend
the
filler neck....it's tight but it should come out with slight
rotations....move the exhaust pipe out of the way for extra clearance to
enable the tank to drop out.
17. With tank out of the car...be sure and wipe/blow off any dirt or
dust
around the fuel sending unit so it doesn't fall in the gas tank when you
remove the sending unit/pump.
18. Remove the sending unit by carefully rotating the round retaining
ring
counter-clockwise. I used a large flat bladed screwdriver and tapped it
with a hammer to slowly rotate the ring and enable the fuel sending unit
to
be removed.
19. With the retaining ring opened, carefully/slowly pull the sending
unit
& fuel pump assembly up and forward to allow the unit to clear the
splash
baffles in the gas tank and come out of the tank. The factory fuel pump
sock is long and a little tough to pull through the gas tank opening but
go
slow and work gently. You don't want to bend your fuel sending unit
float/rod as it will cause your gas gauge to read incorrectly.
Hopefully, at
this point, you have your first look at your old, weak fuel pump that
will
work much better with your new Walbro 340 in it's place!
20. The factory fuel pump can be removed by cutting the black wire and
gray
wire that go into the stock GM pump...the old pump is removed by pulling
downward and out. It will slide out of the pulsator assembly (the
pulsator
looks like a miniature master brake cylinder)...the pulsator slides onto
the
metal fuel line on the sending unit and the other end slides onto the
plastic output port on the fuel pump.
21. Plug the new black and red wiring harness onto the new fuel
pump...it
can only plug in one way... measure the wire length to ensure they can
reach
the just-cut factory gray & black wires...strip off about 1/4 inch
insulation on the ends of the new red & black wires and also on the old
gray
& black wires...use the supplied wire connectors and crimp the black
wire
from the new pump to the black wire coming from the sending unit
ground...crimp the new red wire from the new pump to the gray (power)
wire
from the factory wiring.
22. I re-used the pulsator and slid the new pump outlet into the bottom
of
the pulsator...some folks discard the old pulsator and install a short
1-2
inch neoprene hose and 2 clamps in it's place between the new pump and
metal
fuel line...some feel that the pulsator seals can go bad and cause
potential
start-up problems until the pump re-primes pressure in the line...so
they
use the neoprene line with clamps to eliminate that possibility. Many
folks
have re-used pulsators with no problems...however, John Pearcy
recommends
using the neoprene hose approach instead of the pulsator.
23. I also removed the rubber jacket that went around my old GM fuel
pump
and re-installed it around the outside of the new pump before I slid the
pump into the pulsator. Push the new fabric fuel sleeve/strainer on the
bottom of the new pump and be sure it's tight on the pump. Check your
pump
wires and be sure they can't come in contact with the rod/float on the
gas
gauge. I used a black plastic zip tie to hold the wires to the metal
fuel
line and ensure that they can't touch the float and eliminated the risk
of
my fuel gauge being messed up by contact with the wires.
24. Be sure the rubber o-ring seal is still in the groove on the top of
the
gas tank sending unit access hole...carefully slide the new pump/gauge
assembly into the tank at about a 45 degree angle and be sure it clears
the
interior baffles as it goes back into the tank. The sending unit should
easily sit on the tank after re-installation...hold the sending unit
down
and rotate the retaining ring clockwise by tapping lightly with a flat
blade
screwdriver and hammer until the ring stops rotating at the metal stops.
25. You should be good to go with gas tank re-installation by reversing
the
removal procedure outlined above. Be sure to re-install your coil
springs
in their rubber upper retaining cups before re-jacking up the
axle....remember to bleed rear-brakes to remove air in lines...remember
to
hook up all 4 fuel lines at frame rail. I also recommend you install a
new
fuel filter at the same time you're under there to ensure the best fuel
flow.
Daniel
I followed this description, you cant go wrong if you follow this:
Note: Disconnect the battery in the engine compartment to avoid any
possible
sparks as you're going to be messing around with gasoline...good idea to
have fire extinguisher for backup safety.
1. First thing is to get two jack stands and jack up the rear of the car
as
high as you can...I had my jack stands on the second hole from the
bottom or
as high as my floor jack would raise the car. Put the jack stands under
the
left and right side rear frame rails.
2. Open the gas tank filler door and remove the 3 screws that hold the
white
door to the interior black plastic cup...remove the white door. Unscrew
the
3 screws that hold the black plastic interior cup into the rear quarter
panel. You should now have nothing around the gas tank filler neck and
be
able to see down the filler neck to the gas tank.
3. Remove both rear tires/wheels.
4. Next step is to drop down the muffler from it's mounts on the body.
Driver side has one bolt through a hanging rubber bracket...passenger
side
requires 2 bolts be removed from the mounting bracket that bolts into
the
frame. Carefully lower down the muffler....don't let it fall on you! I
also
unbolted the exhaust pipe from the back of the catalytic (removed two
nuts
holding exhaust pipe flange to catalytic). This is important as it
makes it
a lot easier later if you can move your exhaust pipe/muffler out of the
way
and you won't be able to if it's still bolted to the catalytic.
5. With the muffler hanging down, you can now access the small hex
screws
that hold the thin metal exhaust shields below the gas tank and above
the
rear axle. Remove all these screws and the two separate thin metal
shield
plates from the car.
6. Slide a floor jack under the center of the rear axle and slightly
support
the weight of the rear axle on the jack.
7. There is a flat bar that goes across the rear of the car...it's
bolted to
the driver's side frame with 3 bolts and the other end is attached to
the
passenger side with one long bolt. Remove these bolts and remove the
bar.
This bar is what some of the small hex screws from the exhaust metal
shields
screwed into.
8. The remaining horizontal bar that bolts to the frame on the driver
side
and to the axle housing on the passenger side should also be removed at
this
point.
9. Unscrew the main rear metal brake line from the flexible hose that
goes
to the distribution block on the axle. Remove the flexible brake line
retaining clip that holds it to the metal frame bracket...the flexible
brake
hose should be free from the frame as it could be damaged when you lower
the
axle housing later if it was still attached to the driver side frame
bracket. Some people have said you don't have to un-do the brake
line...but
I recommend you un-hook it and just bleed your rear brakes later to
avoid
damaging any brake lines.
10. Jack up the rear axle slightly to take pressure off the stabilizer
bar....unscrew the 9/16 long bolts that hold the rear stabilizer bar to
the
frame brackets on both the driver and passenger sides. The bolts can be
hard to get off as they rust pretty badly....if you break it,
replacement
poly bushings and bolts are still available/in stock at dealers as they
fit
a lot of years.
11. With stabilizer bar ends disconnected, remove the lower retaining
nuts
on the driver and passenger rear shocks. Carefully slide the shocks out
of
the rear axle mounting holes. Be sure the axle is supported on the
floor
jack as the axle can swing down now as the shocks no longer hold it up.
12. Slowly lower the floor jack to get the tension off the coil
springs...
let the axle drop as far as it can go...don't get nervous when the rear
coil
springs fall out....they are easy to reinstall and just sit on the axle
pads.
13. Find the 4 metal fuel lines by the driver side frame. Two lines
have
screw clamps, one line has a tension clamp and the main pressure line
has to
be unscrewed with wrenches. Remove only the lower clamps on the three
lines
and slowly unscrew the main pressure line to relieve any pressure in the
line. Slide the lines upward off the metal lines coming along the
frame...all fuel lines should be above/disconnected from the metal frame
lines.
14. Slide your exhaust system (muffler/pipe) as far to the passenger
side of
the car as possible above the rear passenger brake rotor assembly...this
will help provide clearance as the tank is removed by sliding down and
towards the passenger side wheel. Unscrew/remove the gas filler cap.
15. At this point, you're ready to unscrew the two long bolts that hold
the
gas tank retaining straps to the underside of the car. I made a point
to
drive my car to almost an empty gas tank to keep the weight of the gas
tank
as low as possible as I was doing the disassembly myself and it's no fun
when you have a heavy/filled gas tank. The tank will be heavy and hard
to
handle if you have a lot of gas in it!!!
16. Remove the two retaining bolts and let the gas tank straps swing
down...be sure and not bend the straps as it makes them much harder to
reinstall...support the gas tank with your hands and slowly slide it
towards
the passenger side of the car. You will need to slide it as far to the
passenger side as you can and then downward to clear a metal lip on the
frame in the gas neck filler area. Don't force anything and don't bend
the
filler neck....it's tight but it should come out with slight
rotations....move the exhaust pipe out of the way for extra clearance to
enable the tank to drop out.
17. With tank out of the car...be sure and wipe/blow off any dirt or
dust
around the fuel sending unit so it doesn't fall in the gas tank when you
remove the sending unit/pump.
18. Remove the sending unit by carefully rotating the round retaining
ring
counter-clockwise. I used a large flat bladed screwdriver and tapped it
with a hammer to slowly rotate the ring and enable the fuel sending unit
to
be removed.
19. With the retaining ring opened, carefully/slowly pull the sending
unit
& fuel pump assembly up and forward to allow the unit to clear the
splash
baffles in the gas tank and come out of the tank. The factory fuel pump
sock is long and a little tough to pull through the gas tank opening but
go
slow and work gently. You don't want to bend your fuel sending unit
float/rod as it will cause your gas gauge to read incorrectly.
Hopefully, at
this point, you have your first look at your old, weak fuel pump that
will
work much better with your new Walbro 340 in it's place!
20. The factory fuel pump can be removed by cutting the black wire and
gray
wire that go into the stock GM pump...the old pump is removed by pulling
downward and out. It will slide out of the pulsator assembly (the
pulsator
looks like a miniature master brake cylinder)...the pulsator slides onto
the
metal fuel line on the sending unit and the other end slides onto the
plastic output port on the fuel pump.
21. Plug the new black and red wiring harness onto the new fuel
pump...it
can only plug in one way... measure the wire length to ensure they can
reach
the just-cut factory gray & black wires...strip off about 1/4 inch
insulation on the ends of the new red & black wires and also on the old
gray
& black wires...use the supplied wire connectors and crimp the black
wire
from the new pump to the black wire coming from the sending unit
ground...crimp the new red wire from the new pump to the gray (power)
wire
from the factory wiring.
22. I re-used the pulsator and slid the new pump outlet into the bottom
of
the pulsator...some folks discard the old pulsator and install a short
1-2
inch neoprene hose and 2 clamps in it's place between the new pump and
metal
fuel line...some feel that the pulsator seals can go bad and cause
potential
start-up problems until the pump re-primes pressure in the line...so
they
use the neoprene line with clamps to eliminate that possibility. Many
folks
have re-used pulsators with no problems...however, John Pearcy
recommends
using the neoprene hose approach instead of the pulsator.
23. I also removed the rubber jacket that went around my old GM fuel
pump
and re-installed it around the outside of the new pump before I slid the
pump into the pulsator. Push the new fabric fuel sleeve/strainer on the
bottom of the new pump and be sure it's tight on the pump. Check your
pump
wires and be sure they can't come in contact with the rod/float on the
gas
gauge. I used a black plastic zip tie to hold the wires to the metal
fuel
line and ensure that they can't touch the float and eliminated the risk
of
my fuel gauge being messed up by contact with the wires.
24. Be sure the rubber o-ring seal is still in the groove on the top of
the
gas tank sending unit access hole...carefully slide the new pump/gauge
assembly into the tank at about a 45 degree angle and be sure it clears
the
interior baffles as it goes back into the tank. The sending unit should
easily sit on the tank after re-installation...hold the sending unit
down
and rotate the retaining ring clockwise by tapping lightly with a flat
blade
screwdriver and hammer until the ring stops rotating at the metal stops.
25. You should be good to go with gas tank re-installation by reversing
the
removal procedure outlined above. Be sure to re-install your coil
springs
in their rubber upper retaining cups before re-jacking up the
axle....remember to bleed rear-brakes to remove air in lines...remember
to
hook up all 4 fuel lines at frame rail. I also recommend you install a
new
fuel filter at the same time you're under there to ensure the best fuel
flow.
Daniel
