Fuel System - Pump Nozzle Shuts OFF/Tank Slow to Fill
TSB SB04-02-S004Vehicle is Difficult to Fill with Fuel or Filling Station
Pump Shuts Off Before Tank is Full or Fuel Spits
Back/Out When Filling the Tank
Affected Vehicles
2003-2004 Isuzu Ascender (7-Passenger / 5-Passenger) models.
Service Information
This bulletin provides information on two different conditions.
Condition 1:
Some customers may comment that their vehicle is difficult to fill with fuel or when filling, the pump continuously shuts off before the tank is full.
Possible Cause:
This condition may be caused by the variability (fuel flow rates, type of fuel fill nozzle, fuel properties) at the filling stations. There is a potential to develop an increase in back pressures internal to the fuel fill neck. This back pressure trips the fuel nozzle prior to filling the tank, or results in a hard to fill condition.
Condition 2:
Some customers may comment that when filling the fuel tank, a small amount of fuel may spit back/out.
Possible Cause:
This condition may be caused by the equalization of pressure between the fuel tank and the fuel fill neck that does not react quickly to the variance in the pressure when the fueling station fuel nozzle trips off.
Correction:
Replace the fuel tank filler upper pipe assembly and lower hose assembly. The new upper pipe has been redesigned to provide smoother flow conditions within the section and the new lower hose has been redesigned to include a checking feature. Use the procedure listed below.
Service Procedure
1. Remove the fuel fill cap.
2. Remove the fuel fill pipe housing.
3. Remove the fuel fill pipe bracket nut (see figure 1).
4. Raise and suitably support the vehicle, refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
5. Remove the fuel fill pipe ground strap bolt.
6. Cut off the ground strap ring terminal and tie strap.
7. Loosen the fuel hose clamp (see (1) in figure 2).
8. Remove the fuel fill upper pipe from the vehicle (see (2) in figure 2.
9. Install the new fuel fill upper pipe into the vehicle, use P/N 8-88983-256-0 for 2003 model year vehicles or P/N 8-15131-043-0 for 2004 model year vehicles.
10. Tighten the fuel hose clamp to 2.5 N.m (22 lb in).
11. Wrap the excess length of ground strap around the fuel hose as necessary.
12. Install the fuel fill pipe ground strap bolt in its original location.
13. Loosen the lower fuel hose clamps (see (3) in figure 2).
14. Remove the lower fuel hose from the vehicle (see (4) figure 2).
15. Install the new lower fuel hose into the vehicle, use P/N 8-15131-046-0.
16. Tighten the clamps to 2.5 N.m (22 lb in).
NOTE:
Make sure that the lower hose assembly is positioned properly. The updated lower hose assembly contains an internal "flapper" valve that moves on a floating hinge. The hinge should be in the 12 o'clock position once the lower hose is installed. Since the hinge is not spring loaded, the "flapper" valve may stay open if the hose is mis-positioned during installation which may cause a repeat concern.
17. Lower the vehicle.
18. Install the fuel fill pipe bracket nut and tighten to 10 N.m (89 lb in).
19. Install the fuel fill pipe housing.
20. Install the fuel fill cap.
Parts Information
Warranty Claim Information
Use the labor operation shown.
Disclaimer