Low fuel pressure at rail swapped to newer gen tank

ELIJAH SHADOWEN

MEMBER
1996 JEEP CHEROKEE
4.0L
6 CYL
2WD
AUTOMATIC
192,000 MILES

I have the vehicle listed above. I know it's a weird one only one to have that certain style fuel tank and zj pdc. Well, had bad fuel so swapped tanks from a 1997 Grand Cherokee. Now I have low pressure at rail swapped a newer pump from my 1999 parts Jeep still low pressure. Bypassed the external filter still low pressure. Any ideas on what could cause this? It'll idle fine at 25-30 PSI, but soon as I get in the throttle she stumbles and shuts off.

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good evening,

The pressure all comes from the pump. The pump you are using is the issue and needs a new pump, not another used pump.

Fuel Pressure

Engine at idle speed .................... 338 kPa ± 14 kPa (49.0 psi ± 2 psi).

As you can see the pressure needs to be higher for the fuel system to work correctly.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Get yourself a new fuel pump and that should get you going.

Roy

FUEL TANK DRAINING AND REMOVAL/INSTALLATION PROCEDURE

WARNING: The fuel system is under constant pressure, even when the engine is OFF. Always release fuel pressure before servicing any fuel system component.

REMOVAL
Perform the fuel system pressure release procedure.

1. Disconnect the negative battery cable.
2. Remove the filler cap. Using a gasoline storage/siphon tank or acceptible substitute, drain the fuel tank.
3. Raise and support the vehicle.
4. Disconnect the fuel fill hose, and vent hose from the filler neck.
5. Disconnect the fuel pump module wire connector. Remove any tie straps securing the connector harness to the fuel hoses.

Fuel Filler Neck Hoses
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6. Disconnect the fuel tank vent hose from vent tube.
7. Disconnect fuel supply hose at pump module.
8. If equipped, remove skid plate.

Fuel Tank With Skid Plate (XJ)
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9. Remove fuel tank shield.
10. Center a transmission jack under the fuel tank.

Fuel Tank Assembly Removal/Installation (XJ)
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11. Remove the tank support strap nuts. Move the straps away from tank.
12. Lower fuel tank on transmission jack.

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