Repeated EFI Fuse Blowing - Clogged Fuel Filter Overworking Walbro Pump

Fuel Systemintermediate✓ OP Confirmed

Problem

Car progressively stuttered and hesitated under boost, then at partial throttle, then died completely. EFI fuse kept blowing repeatedly, each time after about 20-30 miles of driving. Fuel pump was only receiving 2.15 volts instead of 12v. CEL would not flash codes.

Stuttering and hesitation under boostProgressive loss of power - first under boost, then at partial throttle, then at idleCar eventually dies completelyEFI fuse blown (may still look good visually)Only 2.15 volts at fuel pump connectorCEL not flashing any codesTurbo unable to build more than 8-9 psi before problems worsenEFI fuse blows repeatedly after replacement, each time progressively faster

Root Cause

A clogged fuel filter was causing the aftermarket Walbro fuel pump to work excessively hard to push fuel through, drawing more current and generating excessive heat. The increased current draw eventually blew the EFI fuse. Additionally, heat from the turbo had warped the vinyl wrap conduit on the engine harness above the turbo area, exposing wires to even more heat which increased resistance and contributed to the fuse blowing. The Walbro pump's higher output masked the clogged filter symptoms (a stock pump would have simply starved for fuel), making diagnosis harder.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted June 2023 on SupraForums.com