Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Fuel Pressure: Testing and Inspection
Fuel Pump Vacuum Test - Mechanical Fuel Pump
FUEL PUMP VACUUM TEST
1. Disconnect inlet hose at fuel pump and connect a vacuum gauge.
2. Crank or run engine until maximum vacuum is reached. If the vacuum reading is less than (15" Hg.), replace the fuel pump. If more than
(15"Hg.), go to step 3.
3. Check fuel lines and hoses for splits, leaks or kinks by disconnecting each section of line and connecting a vacuum gauge. Crank or run engine
until vacuum reaches it's peak. Vacuum should be at least (15" Hg.). If less, repair or replace the malfunctioning line or hose.
4. If the fuel lines and pump check OK, remove tank unit, replace strainer and clean the tank.
