Low Pressure Fuel Pump Testing & Operation
- Open fuel line at high pressure pump inlet. Connect hose to line from fuel tank. Route hose to a one (1) quart, calibrated container. Disconnect high pressure fuel pump electrical connector from body wiring harness.
- Replace fuel pump relay with modified relay. See MODIFYING FUEL CUT-OFF RELAY
in this article. Ground wire coming from relay to a convenient ground point to energize fuel pump and measure flow for 10 seconds.NOTE: It may be necessary to momentarily block fuel hose to prime low pressure pump with outlet open and no back pressure on outlet; this is normal.
- If fuel pump produces a minimum flow of 16 oz. of fuel in 10 seconds, pump is operating correctly. If there is no flow from pump, check electrical circuit, and also for inlet line restriction. Replace pump if required.