Cummins/Onan — Fuel Pump Flow Test (EFI Gasoline Models)
Testing & diagnosis · Remote fuel pump
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan HGJAA, Cummins/Onan HGJAB, Cummins/Onan HGJAC, Cummins/Onan HGJAD, Cummins/Onan HGJAE, Cummins/Onan HGJAF
Before you start
- Gasoline is flammable; do not smoke; keep ignition sources away
Procedure
- Disconnect fuel return line between genset and tank.
- Collect fuel in a gallon container.
- Prime the genset for exactly one minute.
- Verify flow is approximately 1 quart (0.9 liter) per minute.
- Verify fuel pressure is approximately 45 psi.
- Reconnect the fuel return line.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Flow approximately 1 quart (0.9 L) per minute
- Pressure approximately 45 psi
Full service-parts list: Cummins/Onan HGJAA →, Cummins/Onan HGJAB →, Cummins/Onan HGJAC →, Cummins/Onan HGJAD →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.