Help Please

[PACESETTER]

I Have A 2001 6.6 Duramax Diesel. I Was Going Down The Interstate And Truck Went To Down Shifting And Wouldnt Rev Over 2000 Rpm. I Think That It Is Going Into Limp Mode But The Code Says That I Have A Major Fuel Leak Cant See Any Visual Leaks And Fuel Filter Was Changed Didnt Help The Problem. It Only Goes Into Limp Mode When I'm Pulling A Load.after Unhooking The Battery And Reseting The Computer It Will Run 20or 30 Miles And Do It Again. Oil Looks Fine Doesnt Smell Like Fuel I Dont Think It Was Bad Fuel Because A Buddy Filled Up Off Same Pump An Didnt Have Any Problem. Does Anyone Know What This May Be.thanks

[tx dave]

:mad: I hate to be the one to tell you this but what you are describing is exactly what my 01 was doing right before I had to have the injectors changed. Coded Massive Fuel Leak, no fuel in oil that I could smell. just limped out when pulling my trailer. It only started smoking about a week after this first happened and thats when I took it in for injectors. I had 175K on the truck so Mine was covered under the warranty policy.

[More Power]

The "major fuel leak" description is a bit of a misnomer. It might be that one or more injectors are bypassing more fuel than normal, and is causing a low fuel-rail pressure, but...

One of the more common causes of this is a restrictive fuel filter.

The root cause of this trouble code is that there is more than a 20Mpa pressure difference between the "Commanded" and "Actual" Fuel-rail pressure.

Rule #1 for diesel owners: Always change the fuel filter as one of the first steps in resolving any diesel engine running problem.

Jim

[tall78]

May not be a leak. Sounds to me like you need to replace your Fuel Cap. Pressure not holding.

[DmaxMaverick]

May not be a leak. Sounds to me like you need to replace your Fuel Cap. Pressure not holding.

ECM monitoring of fuel tank pressure unique to gassers. The Diesel fuel cap is vented, in and out. While a failed fuel cap vent could cause issues (and possibly DTC's), "major fuel leak" isn't one of them. A "major fuel leak" only means the PCM can't account for an amount of metered fuel.

[Kennedy]

Fuel filter restriction is first place to check, BUT being a 2001 it is often related to the factory programming and can be easily cured.