Where is the pressure relief valve on a Duramax LBZ?

Where is the pressure relief valve on a Duramax LBZ?

This is the pressure relief valve located in the driver’s side fuel rail on the 2004.5 – 2007 Duramax LLY & LBZ engines. These valves are known to go bad and open prematurely causing a “fuel rail PSI low” problem. Once a valve is weakened it tends to get worse.

Can a fuel rail high pressure relief valve go bad?

These valves are known to go bad and open prematurely causing a “fuel rail PSI low” problem. Once a valve is weakened it tends to get worse. Replacing the valve with a new one is much safer than shimming it and taking your chances with the high (22,000+ PSI) pressures that this valve was designed to protect from.

How long does it take to fix Duramax fuel rail pressure?

Approximate time for the DIY’er would be 6-10 hours. Installing a lift pump may help fix the symptom and is a good modification for the future even if a new CP3 is needed. If a mechanic is out of the question, then installing a quality lift pump would be my first recommendation. High injector return rates.

How can I tell if my Duramax fuel rail is leaking?

Weak fuel pressure relief valve (fprv) for 2004.5-2010 model years. This can be tested by doing the “bottle test” This is an easy, cheap way to see if the fprv is leaking. If any fuel is leaking past the fprv, then the internal spring will need to be shimmed.

What should the pressure be on the fuel rail?

With engine running, observe the Actual Fuel Rail Pressure parameter with a scan tool. A normal reading would be approximately 40 MPa (5,802 psi) with the engine cold, and 30 MPa (4,351 psi) at operating temperature. Inspect the fuel supply lines for damage between the fuel tank and the fuel injection pump.

What should vacuum pressure be on Duramax diesel engine?

Attempt to start the engine. ⇒ If the engine does not start, refer to Engine Cranks But Does Not Run . Install the J 44638 to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT). Vacuum should be less than 5 inches Hg of vacuum.

How does FRP sensor work on Duramax diesel engine?

The FRP sensor uses a 5-volt reference circuit , a signal circuit, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine. • DTCs P0090, P0192, P0193 are not set.