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Why ? You won't fix it , take it to a qualified repair shop before mess it up.This vehicle has a fuel pump driver module (computer) that controls the fuel pump .
Fuel Pump Flow Control Module (FPCM)
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a 25 KHZ PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal. Maximum current supplied to the fuel pump is 15 amps. A liquid fuel pressure sensor provides fuel pressure feedback to the FPCM.
Electronic Returnless Fuel System (ERFS)
The electronic returnless fuel system is a microprocessor controlled fuel delivery system which transports fuel from the tank to the fuel rails. It functions as an electronic replacement for a traditional, mechanical fuel pressure regulator. A pressure vent valve within the fuel tank provides an added measure of fuel pump flow control module (FPCM). Desired fuel pressure is commanded by the engine control module (ECM), and transmitted to the FPCM via a GMLAN serial data message. A liquid fuel pressure sensor provides the feedback the FPCM requires for Closed Loop fuel pressure control.
Could be the fuel pump or or fuel pressure regulator . To test mount a pressure gauge in the fuel line , energize the fuel pump and restrict the flow on the fuel return line , if no build up of pressure replace the pump , if pressure increase replace the regulator.
Here are the usual suspects:
stuck fuel valve/float valve in the carburetor.
clogged fuel filter. or fuel line.
defective fuel pump.
electric fuel pump may be just a blown fuse, or wiring problem. good hunting.
Fuel Pump Flow Control Module (FPCM) - LMF
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a 25 KHZ PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal. Maximum current supplied to the fuel pump is 15 amps. A liquid fuel pressure sensor provides fuel pressure feedback to the FPCM.
Electronic Returnless Fuel System (ERFS) - LMF
The electronic returnless fuel system is a microprocessor controlled fuel delivery system which transports fuel from the tank to the fuel rails. It functions as an electronic replacement for a traditional, mechanical fuel pressure regulator. A pressure vent valve within the fuel tank provides an added measure of fuel pump flow control module (FPCM). Desired fuel pressure is commanded by the engine control module (ECM), and transmitted to the FPCM via a GMLAN serial data message. A liquid fuel pressure sensor provides the feedback the FPCM requires for Closed Loop fuel pressure control.
Fuel Pump Flow Control Module (Gas except LU3/LMG/LY6/LC9)
Mounted to the rear frame, near the spare tire mount
Wheels/Vehicle Underbody Component Views
Component Connector End Views
Fuel Pump Relay - Secondary (Gas with LY6)
On the fuse block - underhood bracket
DTC P0191: Fuel Rail Pressure (FRP) Sensor Performance
DTC P0192: Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage
DTC P0193: Fuel Rail Pressure (FRP) Sensor Circuit High Voltage
DTC P0230: Fuel Pump Relay Control Circuit
The engine control module (ECM) sends the fuel enable signal to the fuel pump control module (FPCM). The control module monitors the voltage on the fuel pump relay control circuit. If the control module detects an incorrect voltage on the fuel pump relay control circuit, a fuel pump relay control DTC sets.
The control module monitors the voltage on the fuel pump relay control circuit. If the control module detects an incorrect voltage on the fuel pump relay control circuit, a fuel pump relay control DTC sets.
DTC P0231: Fuel Pump Control Circuit Low Voltage
DTC P0232: Fuel Pump Control Circuit High Voltage
DTC P023F: Fuel Pump Control Circuit
DTC P025A: Fuel Pump Control Module Enable Circuit
Your best bet , take it to a qualified repair shop , dealer .
Ran a hot wire to what fuel pump or the control module ? Which of these is yours ?
Figure 9: Fuel Controls - Fuel Pump Controls (LY6)
Figure 10: Fuel Pump Flow Control Module (Except LY6) Does yours have fuel pump flow control module under the vehicle Fuel Pump Flow Control Module (except LY6)
Mounted to the left side of the frame assembly below the driver seat ?
Fuel Pump Flow Control Module (FPCM) - LMF
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a 25 KHZ PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal. Maximum current supplied to the fuel pump is 15 amps. A liquid fuel pressure sensor provides fuel pressure feedback to the FPCM.
Electronic Returnless Fuel System (ERFS) - LMF
The electronic returnless fuel system is a microprocessor controlled fuel delivery system which transports fuel from the tank to the fuel rails. It functions as an electronic replacement for a traditional, mechanical fuel pressure regulator. A pressure vent valve within the fuel tank provides an added measure of fuel pump flow control module (FPCM). Desired fuel pressure is commanded by the engine control module (ECM), and transmitted to the FPCM via a GMLAN serial data message. A liquid fuel pressure sensor provides the feedback the FPCM requires for Closed Loop fuel pressure control.
If your vehicle has this system check it for DTC'S - diagnostic trouble codes . Will take guess work out of it .
DTC P0191: Fuel Rail Pressure (FRP) Sensor Performance
DTC P0192: Fuel Rail Pressure (FRP) Sensor Circuit Low Voltage
DTC P0193: Fuel Rail Pressure (FRP) Sensor Circuit High Voltage
DTC P0230: Fuel Pump Relay Control Circuit
DTC P0231: Fuel Pump Control Circuit Low Voltage
DTC P0232: Fuel Pump Control Circuit High Voltage
DTC P023F: Fuel Pump Control Circuit
The engine control module (ECM) supplies voltage to the fuel pump flow control module (FPCM) when the ECM detects that the ignition is on. The voltage from the ECM to the FPCM remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the FPCM supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.
DTC P025A: Fuel Pump Control Module Enable Circuit . Ford Electronic Returnless Fuel System Diagnosis Part 1 this for ford but the GM system works the same . You'll need a wiring diagram so you know what wires are what . Free wiring diagrams http://www.bbbind.com/free_tsb.html
Your vehicle has no fuel pump relay . Has a fuel pump flow control module .
Fuel Pump Flow Control Module (FPCM)
The fuel pump flow control module (FPCM) is a serviceable GMLAN module. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and controls the fuel pump located within the fuel tank to achieve the desired fuel pressure. The FPCM sends a PWM signal to the fuel pump, and pump speed is changed by varying the duty cycle of this signal.
Plus it has two fuel pumps !
The high pressure fuel pump (9) is a mechanical one cylinder design driven by an eccentric on the exhaust camshaft (1) of bank 2. High pressure fuel is regulated by the fuel rail pressure (FRP) regulator, which is a part of the high pressure fuel pump. The FRP regulator is a magnetic actuator which controls the inlet valve of the high pressure pump. The ECM provides battery voltage on the actuator high circuit and ground on the actuator low reference circuit. Both circuits are controlled by the ECM. When the ECM deactivates the FRP regulator, both circuits are disabled and the inlet valve is held open with spring pressure. When the ECM activates the FRP regulator, the low circuit driver connects the low reference circuit to ground and the high circuit driver pulse-width modulates (PWM) the high circuit. The ECM uses the camshaft and crankshaft position sensor inputs to synchronize the FRP regulator with the position of the eccentric on the camshaft. The ECM regulates fuel pressure by adjusting the portion of each pump stroke that provides fuel to the rail. The high pressure fuel pump also contains an integrated pressure relief valve.
Your best bet is have it towed to the dealer , you don't want to mess with the high pressure pump .
Pluse
You connect a fuel pressure gauge like this to the pressure rail. Pressure in this car must be between 35 and 45 psi. If pressure is too low look for kinked fuel lines and eventually replace the pump. If the pressure drops down more than 10 psi in five minutes or if the pressure is considerably higher than that replace the fuel pressure regulator. Below the parts that may need testing:
Inside The Fuel Tank. If Yours Tests Bad, You Will Need To Drop The Tank And Replace It. Be Sure To Have Someone Test To Make Sure Yours Is Bad, This Is A Difficult Job And Expensive.
See Figure 1
Two different electric fuel pump configurations were used on fuel injected models. One consists of a low pressure in-tank boost pump in conjunction with an external, frame-mounted high pressure pump. The low pressure pump is used to provide pressurized fuel to the inlet of the high pressure pump and helps prevent noise and heating problems. System pressure is controlled by a pressure regulator mounted on the engine.
The other configuration consists of an in-tank high pressure pump which does not utilize a boost pump.
Fig. Fig. 1: Disassembled electric fuel pump
REMOVAL & INSTALLATION
In-Tank Pump
See Figures 2, 3 and 4
Disconnect the negative battery cable.
Depressurize the system and drain as much gas from the tank by pumping out through the filler neck.
Raise and support the rear end on jackstands.
Disconnect the fuel supply, return and vent lines at the right and left side of the frame.
Disconnect the wiring to the fuel pump.
Fig. Fig. 2: Low pressure in-tank electric fuel pump
Fig. Fig. 3: High pressure in-tank fuel pump
Fig. Fig. 4: Removal of electric fuel pump
Support the gas tank, loosen and remove the mounting straps. Remove the gas tank.
Disconnect the lines and harness at the pump flange.
Clean the outside of the mounting flange and retaining ring. Turn the fuel pump lock ring counterclockwise and remove.
Remove the fuel pump.
To install:
Clean the mounting surfaces. Put a light coat of grease on the mounting surfaces and on the new sealing ring. Install the new fuel pump.
Installation is in the reverse order of removal. Start the vehicle and check electric fuel pump operation. Check for fuel leaks.
High Pressure External Pump
See Figure 5
Disconnect the negative battery cable.
Depressurize the fuel system.
Raise and support the rear of the vehicle on jackstands.
Disconnect the inlet and outlet fuel lines.
Detach the electrical harness connection.
Bend down the retaining tab and remove the pump from the mounting bracket ring.
Install in reverse order. Make sure the pump is indexed correctly in the mounting bracket insulator. Start the vehicle and check electric fuel pump operation. Check for fuel leaks.
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