Question about 1991 GMC S-15 Jimmy

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FUEL PUMP DRAINING FUEL BACK INTO TANK WHEN ENGINE IS SHUT OFF

I HAVE A 1991 GMC JIMMY WITH A 4.3 THOROTTLE BODY . (TBI), IM HAVING TROUBLE WITH IDLE AND STARTING, WHEN I SHUT ENGINE OFF OR IT QUITS, I CAN HERE FUEL DRANING BACK INTO TANK, IS THIS NORMAL OR DOES THE FUEL PUMP HAVE A CHECK VALVE BUILT IN TO IT THAT IS SUSPOSE TO PREVENT THIS.

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  • JWOSBORNE Jan 07, 2009

    IT DOES HAVE A PRESURE REGULATER

  • John Jon May 11, 2010

    fuel presure regulator valve "if" equiped!?

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  • Master
  • 2,692 Answers

The fuel is in a continous loop being available at  all times to the TBFI. It has the return path so it can always return to the tank via the return line. Np check valve as the pump runs all the time.

Posted on Jan 07, 2009

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1 Answer

Where is the fuel pump relay on a 1991 gmc jimmy


Thye fuelpump relay is located to the right of the brake booster. this is for a 1991 gmc jimmy (s-15)

I have enclosed a diagram to help locate the relay.

The most common reason for no fuel pressure on these trucks is not the relay but rather the fuelpump itself. the pump is located inside the fuel tank.

There is also a problem with the wiring to the fuel pump, you will need to locate the top of the tank and then off to side of tank is wiring .
This wiring comes off the top of the tank, you will need to check and there is connector problems..
there is one or two ground wires that come off wiring to top of tank which run to frame, check to make sure the grounds are good. if you end up with a bad pump you will see a notice to rewire a new fuelpump connector. hope this is helpful. good day.3_4_2012_1_29_16_am.gif

Mar 03, 2012 | 1991 GMC S-15 Jimmy

2 Answers

Fix fuel pump


Removal & Installation To Remove:
  1. Properly relieve the fuel system pressure.
  2. Drain the fuel tank through the filler pipe.
  3. Support the fuel tank.
  4. Remove or disconnect the following:
    • Negative battery cable
    • Filler neck
    • Shield and tank straps
    • Fuel lines and vapor hose from pump and tank
    • Electrical connection from fuel pump
    • Fuel tank
    • Fuel pump/sending unit assembly by turning the locking ring (located on top of the fuel tank) counterclockwise using a spanner wrench
    • Fuel pump from the fuel lever sending device
To Install:
  1. Install or connect the following:
    • Fuel pump in tank with new seal around opening
    • Tank and connect fuel lines and vapor hose
    • Tank to the frame
      1. Torque to: 33 ft. lbs. (45 Nm)
    • Shield
    • Fuel filler neck and clamp
    • Negative battery cable
  2. Refill the tank.
  3. Run the engine and check for leaks.
View of the in-tank fuel pump assembly. 7924jg21.gif

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Nov 06, 2010 | 1997 GMC Jimmy

1 Answer

Where is fuel pump located


Electric Fuel Pump REMOVAL & INSTALLATION CAUTION
The 220 TBI unit has a bleed in the pressure regulator to relieve pressure any time the engine is turned off, however a small amount of fuel may be released when the fuel line is disconnected. As a precaution, cover the fuel line with a cloth and dispose of properly. Fig. 1: Electric fuel pump - TBI engines 84905028.gif
  1. With the engine turned OFF, relieve the fuel pressure at the pressure regulator. Refer to the fuel relief procedure in this section.
  2. Disconnect the negative battery cable.
  3. Raise and support the rear of the vehicle on jackstands.
  4. Drain the fuel tank, then remove it.
  5. Using a hammer and a drift punch, drive the fuel lever sending device and pump assembly locking ring (located on top of the fuel tank) counterclockwise. Lift the assembly from the tank and remove the pump from the fuel lever sending device.
  6. Pull the pump up into the attaching hose while pulling it outward away from the bottom support. Be careful not to damage the rubber insulator and strainer during removal. After the pump assembly is clear of the bottom support, pull it out of the rubber connector. To install:
  7. Connect the fuel pump to the hose. NOTE: Be careful that you don't fold or twist the strainer when installing the sending unit, or you'll restrict fuel flow.
  8. Install a new O-ring on the pump assembly and then position them into the fuel tank.
  9. Turn the locking ring clockwise until its tight.
  10. Install the fuel tank and connect the battery cable.
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Oct 13, 2010 | 1988 GMC Jimmy

1 Answer

4.3 TBi code Z cuts out at idle. Please Help!!


Try cleaning the IAC VALVE in the opening in the throttle body with throttle body cleaner,clean well or replace IAC VALVE ( idle air control ) .

Mar 27, 2010 | 1992 GMC Jimmy

1 Answer

Where is the fuel pump relay for a 1991 gmc jimmy?


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  • REPAIR INFO bc_arrowbullet1.gif
  • COMPONENT LOCATIONS bc_arrowbullet1.gif
  • COMPONENT LOCATIONS RESULTS
Relay - Fuel Pump 1991 GMC Truck S15 Jimmy 2WD 4.3L TBI 6cyl The Relay - Fuel Pump Under hood, driver side, upper firewall, mounted in relay block

Jul 02, 2009 | 1991 GMC S-15 Jimmy

3 Answers

My gmc s-15 jimmy 4x4 wont stay running. When i try to crank i have to press the gas pedal and keep it pressed otherwise it will shut off. What can be causing this


These trucks were equipped with a TBI, (Throttle Body Injector). This looks like a modified Carburetor with two large fuel injectors placed over a two barrel throttle plate and venturi body. You need to check the base gasket on this TBI Unit. The base gaskets were notorious for becoming brittle and cracked . If you remove the air cleaner and open the throttle plates you may see a chunk of black hanging out down below the throttle plates. If you see this, this is the base gasket and it cracked and needs to be replaced.
The Idle Air Control Solenoids were also an issue on these truck too. This is a round part that will have a plug on it normally near the base of the TBI Unit. This will just require a quick replacement.

The last thing that it might be is the electronically controlled EGR Valve. This valve used to cause some trouble from time to time, and I know there was a warranty campaign on these parts. the valve will need to be replaced or cleaned if this is the case.

Good luck and hope this helps friend, Keep me posted and here is a link for you to retrieve DTC codes. http://www.troublecodes.net/GM/

Jul 01, 2009 | 1989 GMC S-15 Jimmy

1 Answer

Fuel pump not pumping


You can Hear fuel running? Where in the tank? If so then it sounds like the fuel pump dettached from the supply line inside the tank.

Jan 11, 2009 | 1991 GMC S-15 Jimmy

2 Answers

JUST DONT WANT TO RUN


Check the fuel pump.

Jan 09, 2009 | 1991 GMC S-15 Jimmy

1 Answer

FEELS LIKE GETTING NO GAS


cHECK THE FUEL PRESSURE AT THE RAIL. iF LOW i WOULD CHECK THE INLINE FILTER AND THEN A POSSIBLE PUMP

Jan 09, 2009 | 1991 GMC S-15 Jimmy

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