How to Check Fuel Pressure on a 5.9 12V Cummins
by Andrea WalkThe Cummins 5.9-liter, 12-valve engine is a large diesel engine that eventually became the stock engine for the Dodge Ram pickup during the 1990s and 2000s. If the Ram has possible fuel-related problems, then running a fuel-pressure test can isolate them. These engines come equipped with an easy-access test port, referred to by some as a Schrader valve. The fuel-pressure gauge can be screwed directly onto this port for testing.
Step 1
Pop the hood on the Dodge Ram and locate the test port on the left-hand front side of the engine compartment.
Step 2
Unscrew the valve cap and pull it back out of the way. Screw the end of the fuel-pressure gauge onto the test port.
Step 3
Start the Dodge Ram and allow it to run for around five minutes. Examine the fuel-pressure reading. If it still appears to be fluctuating, give it a few more minutes until the level peaks out. The pressure should read between 15 to 18 psi.
Step 4
Turn the motor off and remove the pressure gauge from the test port. Use an old towel to wipe up any spilled fuel. Replace the test port cap.
References
- Cummins Diesel Specs
- "Dodge Pickups: 2002 thru 2005 - Full-Size Models 2WD & 4WD - V6 V8 and V10 Gasoline Engines & Cummins Turbo-Diesel Engines (Haynes Repair Manual)"; John A Weggman; 2006
- Youtube: Fuel Pressure Test
Things You'll Need
- Fuel-pressure gauge
Writer Bio
Andrea Walk began writing in 2001, authoring user guides for technical software. She holds a Bachelor of Arts in political science from Loyola University, where she was a member of the Dean's Grade Review Committee for English. Walk is a member of the Automotive X-Prize team Global-E.
