Need Help ASAP! Fuel pressure issue - Chevy and GMC Duramax Diesel Forum
04.5-05 LLY Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 8 (permalink) Old 11-19-2012, 04:32 PM Thread Starter
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Need Help ASAP! Fuel pressure issue

Here is what I have done. Have 05 Durmax with 206k. I have changed the fuel filter housing, filter, (whole unit) and the two hoses that are connected to it. I also flushed the fuel cooler and the fuel likne go back to the tank and cooler with air.

Here is the problem: I am trying to leaving with the Fifth Wheel tomorrow at 6pm central.

When driving with no load over 68 or 50 with a heavy load I lose power and can only do 66 with no laod or 35 with the load. I would say it feels like it is not getting enough fuel.

I had a friend use a GM computer to pressure test the fuel system. When the pressure gets to 160 MPA it bogs then the test defaults. It will not get over 160.

Thanks for the help
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post #2 of 8 (permalink) Old 11-19-2012, 04:35 PM
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Moved to lly area

Originally Posted by Jeremy Clarkson View Post
Some say he was conceived in a cargo van
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post #3 of 8 (permalink) Old 11-19-2012, 04:37 PM Thread Starter
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post #4 of 8 (permalink) Old 11-19-2012, 09:09 PM
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I had the same prob with my 05, the prob with mine was the fuel pressure release valve. I replaced it with what they call a race valve (plug) and have not had a minutes problem since.

2005 GMC 2500 LLY
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post #5 of 8 (permalink) Old 11-20-2012, 03:27 AM
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Bottle test it right away (at 160 MPA) and shim it if it's leaking.

2005 Silverado EC/SB, LLY, 4WD, EFI DSP5 V2 (Idaho Rob at ATP), Edge CTS w/ EGT probe, LML Exhaust Manifold, PPE shimmed FPRV, Banks LBZ air cleaner, Profab intake, LBZ Turbo Mouthpiece, Kennedy twin lift pumps w/ megafilter, Corsa 304 SS Exhaust, Mike L tranny cooler, EXAXT Steering System, Redhead Power Steering Box w/ Amsoil PS fluid, Green Torsion Keys, Allison Deep Pan w/ Suncoast Filterlock and Transynd ATF, Bilstein 5100's (Norcal), Cognito UCA's, 17" NBS alloy rims, 265/70R17 Michelin LTX M/S2's, Pioneer AVH-P3200BT, CubbyCam Backup Camera, Pop & Lock Power Tailgate Lock, Extang Solid Fold Tonneau Cover, Tekonsha P3 Brake controller, Alphatherm AT-38OD Washer Fluid Heater
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post #6 of 8 (permalink) Old 11-20-2012, 06:03 AM
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Here is some info on the "Bottle Test".

On the drivers side fuel rail-- to the back and next to the Turbo, you will see a "U"
shaped 3/8 hose-- remove the hose from the fuel rail-- and plug the hose.

Now attach a 3/8 hose to the fuel rail nipple, and stick the end in a bottle. Now drive the truck hard-- with several wide open runs-- if there is any fuel in the bottle the FPRV [fuel pressure relief valve] is leaking main pressure from the fuel system.

The FPRV is a plug looking part that screws in the back of the driver's fuel rail. Many just increase the pressure with a couple washers, to help hole the pressure. Others use a "Race" plug [not recommended] available from supporting vendors.

Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.
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post #7 of 8 (permalink) Old 11-23-2012, 04:02 AM
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This is good info.Thanks jc1843.

2008 LMM Silverado 2500 LTZ ECSB 4X4.
Aftermarket DSP5 calibration by Danville Performance, Blocked and re-routed, Nicktane with Baldwin BF7587, PPE lift pump with Baldwin BF1212 water separator, 285/75/17 Dura Grapplers on H2s, CTS Insight with pyro.HIDs in fogs and high beams.

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post #8 of 8 (permalink) Old 11-23-2012, 04:05 PM
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If it limped the engine... 66 mph in high gear at 2000 RPM, it will have a code.

Read that code. If you have restarted the truck, the code maybe in historical code storage. Takes a good code reader to see the non current codes. But they are as critical as current codes.

Let us know what code it has. With out the code it is a crap shot to diagnose. And you don't want to waste money on a guess. The above suggestions are valid if that happens to be the problem. But there are a dozen or more reasons why it will limp. Code first, then diagnostic charts, then step through the repair steps.... maybe quick/easy or more complicated.


'05 Chev, 2500HD, CC, SB, Duramax, Allison, 4WD, bought new April '05-times up - off warranty, now 120,000 miles, LBZ mouthpeice, Blocker Plate & Unplugged EGR, Air Box cut out, lost the cat, 52 US Gal (196 Litre) Titan Fuel Tank, SuperChips tuner on Tow mode, AirLift air bags, BrakeSmart Trailer Brake controller, PaceEdwards cover, DSP Fifth Hitch, JVC KW-NT1 headunit, "AutoEnginuity" scanner/reader/monitor.
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