Hummer H1 (2002+). Manual - part 41

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Fuel, Emissions, and Exhaust 3-25

5745159

Fuel Level Transmitter/Pump/Vents/ Access
Plate Replacement

The fuel level transmitter, vents, and access plate can all be
serviced once the tank is out of the vehicle (Figure 3-34).

If the fuel tank requires replacement, be sure to replace all nec-
essary gaskets, O-rings, seals, and strainer with new parts. Coat
fitting threads with Loctite PST before installation.

Tank Cleaning

In cases where the tank was removed for correction of contam-
ination, remove the transmitter, fuel pump, and access plate for
maximum access. Use a soap and water solution and low pres-
sure steam gun. Be sure to clean out the fuel supply and return
lines as well. The tank can be dried with compressed air or al-
lowed to air dry as desired.

Figure 3-34: Fuel Tank and Components

FUEL TANK

FUEL LINE

FUEL LEVEL

GASKET

INNER REAR STRAP

SHIELD

VENT FITTING

AND INSULATOR

TRANSMITTER

SUPPORT

BRACKET

ACCESS PLATE

INNER FRONT STRAP

AND INSULATOR

MAIN

PLUG

SHIELD

INSULATOR

BOTTOM

OUTER

ACCESS PLATE

O-RING (12)

FRONT STRAP

RETAINER

FUEL TANK

BOTTOM

STRAP

OUTER

REAR

STRAP

SPACER

VENT LINE

ACCESS PLATE

FUEL

TANK

JUMPER

HARNESS

STRAINER

FITTING

GASKET

SPACER

INSULATORS

3-26

Fuel, Emissions, and Exhaust

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Main Fuel Tank Installation

NOTE: If tank was replaced, or if transmitter, pump, fitting, or
access plate was replaced, verify that components are properly
seated and secured. Refer to Fuel Level Transmitter and Tank
Access Plate Service procedure in this section.

Position tank on jack and raise tank just enough to permit
installation of wires and lines.

Connect fuel lines as follows:

Push lines onto tank supply and return tubes. Note
that fuel supply tube is larger in diameter than the
return tube.

Push line onto tank tube until it snaps or clicks into
place.

Pull on lines to verify secure attachment.

Connect wiring and vent lines. Also connect rollover valve
line.

Install filler neck-to-tank hose on fuel tank. Secure hose
with new clamp if required.

Position tank and install bolts and nuts that attach tank
upper to lower retaining straps. Tighten strap bolts to 23-
27 lb-in. (3 N•m) torque.

NOTE: If the upper and lower straps touch after bolt tighten-
ing, replace the straps. They are stretched or distorted and will
not adequately secure the tank.

Install propeller shaft.

Connect tank vent lines.

Lower vehicle

Install filler neck and connect ground strap.

10. Install filler neck housing and connect vent line.

11. Refill tank.

12. Start engine and verify proper operation. Repair any leaks

if necessary.

AUXILIARY FUEL TANK

Removal

Drain auxiliary fuel tank. Drain tank with air powered por-
table drain equipment.

Remove tank filler neck housing from wheel house.

Remove bolts attaching auxiliary tank fuel filler neck and
housing to body.

Disconnect filler neck at tank and vent line at housing.

Support auxiliary tank with floor jack positioned under
tank skid plate.

NOTE: Do not loosen or remove the bolts attaching the tank to
the skid plate. The tank and skid plate will be removed as an
assembly.

Remove bolts and nuts attaching tank skid plate to left and
right frame brackets and rear crossmember.

Lower tank enough to reach fuel lines. Then disconnect
fuel lines, fuel level transmitter wires, and vent line. Mark
lines and wires for assembly reference.

NOTE: The fuel supply and return lines are equipped with
quick connect fittings. To disconnect, first lift and remove the
fitting retainer from each fitting. Then pull the fittings free of
the tank fuel tubes.

Lower the jack and remove the tank from under the
vehicle.

Replace fuel level transmitter and access plate
(Figure 3-34). Refer to next procedure in this section.

Installation

If new tank is being installed, transfer tank skid plate to
new tank.

Place tank on floor jack and position it under vehicle.

Raise tank enough to reach feed lines.

Attach vent line and fuel level transmitter wires.

Connect fuel lines. Push each line onto tank tube. Secure
lines with retainers. Be sure retainers are firmly seated in
line fittings.

Raise and align tank skid plate with frame brackets and
rear crossmember.

Install tank attaching bolts and nuts and tighten securely.

Install filler tube housing and fuel filler cap.

Install filler tube shield in wheelhouse.

10. Refill fuel tank.

11. Verify tank operation and fuel level reading.

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Fuel, Emissions, and Exhaust 3-27

5745159

Figure 3-35: Auxiliary Fuel Tank Components

TANK

FUEL LEVEL

GASKET

JUMPER

AUXILIARY

SKID PLATE

FRAME

ACCESS PLATE

O-RING (8)

ROLLOVER

ACCESS PLATE

FUEL

ACCESS

PLATE

TRANSMITTER

STRAINER

HARNESS

FUEL TANK

GASKET

VALVE

RETAINER

MOUNTING

BRACKETS

3-28

Fuel, Emissions, and Exhaust

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FUEL LEVEL TRANSMITTER AND TANK ACCESS
PLATE SERVICE

Removal

Remove screws, lockwashers and fuel level transmitter
from tank access plate (Figures 3-34 and 3-35).

Remove locknuts, washers, access plate and gasket from
tank.

Remove access plate retainer and O-rings from tank.
Discard O-rings.

Check fuel level transmitter operation as follows:

Hold transmitter in the upright or empty position
(Figure 3-36).

Using an ohmmeter, check resistance value at terminals.
Resistance should be 268 ± 20

Hold transmitter in the inverted position simulating a full
tank. Resistance should fall to 19.3 ± 8

Figure 3-36: Fuel Level Transmitter in

Upright or Empty Position

Installation

CAUTION: Do not overtighten access plate or transmitter fas-
teners. Gasket damage and improper sealing could result.

Thoroughly clean all gasket surfaces.

Place new O-rings on access plate retainer studs and
position access plate retainer in tank (Figures

3-34

and 3-35).

Set gasket and access plate over studs and onto tank.

Apply liquid teflon thread sealant to studs and loosely
install washers and locknuts until no clearance exists
between access plate, gasket and tank.

Snug access plate locknuts in small increments and in a
systematic circular pattern. Tighten locknuts until gasket
bulges or until maximum torque of 72 lb-in. is obtained.

Apply liquid teflon thread sealant to transmitter mounting
screws.

Secure gasket and transmitter to access plate using same
method as indicated for access plate above.

Cap all tank fittings and perform leak check. Apply leak
check solution or soapy water around access plate and
transmitter gaskets and fasteners. Pump 3 p.s.i. of
compressed air into tank and verify absence of leaks.

Quick Connect Fittings

Quick connect fittings are used at the main tank fuel tubes,
auxiliary tank fuel tubes, and at the fuel tank selector valve.

Two types of fittings are used. One type is an all plastic push
on style with removable retainer. The second style is a metal,
one-piece fitting with an internal tension clip to retain it. The
plastic fitting retainer only requires a screwdriver and needle-
nose pliers to remove. The metal fitting requires a release tool,
such as J–37088-A, in order to disconnect it.

The metal fittings are used at the main tank. The plastic, two-
piece fittings are used at the auxiliary tank and fuel selector valve.

Metal Fittings

To disconnect, slide the release tool onto the line and into
the fitting.

Press the tool inward to unseat the internal clip and pull
the line off the fuel tube.

To reconnect, just push the fitting onto the line until it
snaps or clicks into place.

Pull on the fitting afterward to verify proper seating.

Plastic Fittings

To disconnect, raise the retainer tab with a small flat blade
screwdriver and remove the retainer with needlenose pliers.

To reconnect, push the fitting onto the tube, insert the
retainer through the fitting sides, and seat it firmly.

Be sure the retainer seats behind the fuel tube flange.

Pull on the fitting afterward to verify proper seating.

GASKET

SCREW

LOCKWASHER

TRANSMITTER

FLATWASHER

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