You will find that GM Trucks are a common source of aftermarket fuel repair jobs. Predominantly, model years from the mid-1990s to current models have known repair problems with the following components:
- The OE roller vane-style pump is under-designed for the high pressure of the CPI fuel system and its high electrical draw can melt the weak connectors.
- The OE pump design is ill-suited to the vibration and shock that the trucks encounter while in service.
FIND OUT WHY the failure occurred before buying parts:
Is there less than 13.5 volts at the pump?
- The repair requires a new wiring harness.
- Note that Carter® includes wiring harnesses in the box for applications with known wiring issues.
Is the gas tank rusting inside or rusted through?
- The repair requires a new tank.
Is the strainer black with grime? Or discolored, appearing packed with contaminants?
- The repair requires you to wash out the contamination and dry the tank.
- Carter offers a robust turbine pump that is one of the best on the market, but all professionals know that installing a pump without cleaning the tank will lead to a comeback within a few months!
Fuel Pump Wiring Harness – mid-to-late 90s GM trucks with hanger assemblies
On certain GM in-tank electric pump hanger assemblies, a faulty electrical connector can cause severe voltage drop (or total loss of voltage) to the pump, a failure mode that often leads to improper diagnosis. Always remove and inspect the hanger wire harness when servicing these pumps! First inspect the electrical connector at the pump and underside of hanger. A “sooty” carbon deposit on the plastic connector, or melted wire insulation, could be a sign that the real problem is not the pump, but the wire harness. Replacing the pump without correcting the wiring will simply lead to another premature failure.
Carter offers “Fuel Tech Solutions” replacement wire harnesses for a full range of GM in-tank hanger assembly applications. Carter wire harnesses include wire insulated with “ETFE” grade covering which is resistant to corrosive fuel blends. The wire terminals are brilliant copper, resulting in improved conductivity and corrosion resistance. Plus, the cover connector and pump connector are manufactured of glass-filled nylon, providing superior rigidity, dimensional integrity and longer product life.
Vehicle to Fuel Pump Module Wiring Harness –
late 90s to current GM trucks with fuel pump modules
Certain GM fuel pump applications are prone to electrical connector failures. Usually, the electrical connector on the vehicle wiring harness that plugs into the fuel pump module is at fault. The positive or negative terminal within this connector begins losing continuity, creating a substantial voltage drop. The heat generated from the arcing and voltage drop melts the plastic around the positive or negative terminal. Where the terminal protrudes from this plastic connector, the plastic should have a pyramid shape. The heat generated by a failed terminal will cause the plastic around it to melt into a spherical shape. In other instances a blackening of the plastic around the terminal will be evident. The location of this faulty connection makes it impossible to diagnose the problem using a voltage drop test. So it’s important to carefully inspect the connector on the old module and the connector on the vehicle body harness for evidence of this failure.
If a failure is suspected, the section of the vehicle wiring harness with the faulty connector must be replaced. If your vehicle requires the white 4-pin, four-cavity connector, purchase Carter® connector repair kit 888-553. If it requires the black 4-pin, four cavity connector, purchase kit 888-543. If it requires the 4-pin or 5-pin, six-cavity connector, purchase kit 888-544.
Carter wire harnesses for GM module assemblies include:
- Wire insulated with “ETFE” grade covering
- Brilliant copper wire terminals
- Glass-filled nylon cover connectors and pump connectors
Special addendum to GM vehicle to module wiring harness
GM announced a wiring harness recall in 2005 regarding the Suburban model years 2000-2001. However, GM has issued a dealer bulletin to repair Metri-Pac® 150 connectors on the following trucks and SUVs:
- 1999-2003 Cadillac Escalade
- 1996-2001 Chevrolet Suburban
- 1996-2003 Chevrolet Silverado, Tahoe
- 1996-2001 GMC Suburban, Yukon XL
- 1996-2003 GMC Sierra, Yukon, 1500 Series Only:
Excludes: E85 Flexible Fuel Vehicles (VIN Z – RPO L59), Diesel Vehicles VINs F, S, Y, 1 – RPOs L65, L56, L57, LB7
Ask your Carter representative for the latest information on upgraded harness connector options.
Download These Helpful Bulletins
- Fuel Tech Solution #1 GM hanger wire harness
- Fuel Tech Solution #9 GM truck fuel pump module
- TEC Bulletin #1620 Comprehensive Guide to Proper Fuel Pump Installation
- TEC Bulletin #1621 E85 Fuel Information
- TEC Bulletin #1622 Fuel Tank Contaminants
- TEC Bulletin #1623 CPI Spider Assembly