Cummins/Onan — Test fuel transfer pump pressure
Testing & diagnosis
From a Cummins/Onan service manual covering: 205D3A, 3DJA, 3DJA-1E2236, 3DJA-3E2236. Check it applies to your exact model before use.
Applies to: Cummins/Onan DJA engine
Procedure
- Remove pump outlet and install pressure gauge.
- Run engine at governed speed with gravity fuel feed.
- Gauge should show 3-1/4 to 4-1/2 psi.
- Gauge must be 16 in. above the fuel pump.
- Low or high reading indicates pump overhaul or replacement.
Tools required
- Pressure gauge or manometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 3-1/4 to 4-1/2 psi with gauge 16 in. above pump
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.