How do I know if my fuel pressure regulator is bad on my Duramax?
The symptoms of a bad regulator usually manifest as a surge when idling, though sometimes the surge can happen at speed while driving. Other symptoms include power loss on acceleration or hard starting. Sometimes it can get bad enough to force the truck into limp mode with a low rail pressure warning.
Where is the fuel pressure relief valve on a LB7?
The lb7 motor as a FPRV just like the lly and lbz motors, except its in a harder to get to location and most of the time its not needed anyway. The location of the FPRV is located on the fuel junction block in the middle of the valley underneath the metal turbo inlet.
What is the fuel pressure on a LB7 Duramax?
Note that the fuel rail pressure is at 24,053 psi. As stated previously, the fuel pressure with the Ignition relay unplugged needs to be a minimum of 2500 to 3500 psi during cranking for the return rate test results to be valid.
What causes low fuel rail Duramax?
It could be a restriction or a leak on the supply line between the fuel tank and the injection pump. It could be a weak injection pump not able to increase fuel pressure up to the maximum under load. It also could be one or more injectors have high return rate.
How do you fix a low fuel rail pressure on a LBZ Duramax?
Inspect fuel lines from fuel filter to injection pump and from CP3 to fuel rails for any leaks or damage. Change your fuel pressure relieve valve to a Race Fuel Valve (solid valve replacement) The spring in the factory valve often wears out and can relieve pressure at a much lower pressure than it should.
How much fuel pressure should a LB7 have?
On a LB7 at full temp its about 4600-4800 PSI.
How long does it take to replace LBZ fuel pressure regulator?
The time taken to accomplish this was around 1.5 to 2 hours. If you don’t have all the tools listed below it may be slightly difficult to accomplish in that time frame. The Design of the LBZ FPR allows you to push higher fuel pressure through your truck because the LBZ FPR has more points to monitor pressure.
How to install a fuel pressure regulator on a Duramax?
1. Remove the air intake pipe. Refer to Air Intake Pipe Replacement . 2. Disconnect the air conditioning (A/C) compressor clutch electrical connector. 3. Disconnect the A/C cut out switch electrical connector. 4. Remove the drive belt.
How to clean a GMC Duramax fuel pump?
Clean the fuel pressure regulator and high pressure injection pump thoroughly with solvent, such as GM P/N 12377981 (Canadian P/N 10953463), or equivalent. 23. Using compressed air, thoroughly blow dry the regulator and pump. 24. Remove the 3 fuel pressure regulator screws (1) using a T25 TORX®. Click here for detailed picture of above image. 25.
Why does the LBZ FPR measure fuel pressure?
The Design of the LBZ FPR allows you to push higher fuel pressure through your truck because the LBZ FPR has more points to monitor pressure. It can provide a more accurate reading than the prior versions could.