G 3500 1 Ton Van V8-379 6.2L DSL VIN J FI (1992)
Fuel Pressure: Testing and Inspection
Fuel Pump Vacuum
Pre-Inspection:
1. Make certain that there is fuel in the tank
2. Check for leaks at all fuel connections from the fuel tank to the injection pump
3. Start engine allowing it to run
4. Tighten any loose connections
5. Inspect all hoses for flattening or kinks that could restrict the flow of fuel
6. Check for air leaks or restrictions on the suction side of the fuel pump, which could seriously affect pump output.
Procedure:
1. Disconnect the inlet line at the fuel pump
2. Plug the hose or position it so fuel does not leak
3. Connect a vacuum gage to the fuel pump inlet
4. Crank or run the engine, vacuum should be 41 kPa (12 inches Hg) or greater
5. If vacuum is below specification, replace fuel pump
