fuel lines

truck04 · January 11, 2006

I have a 2004 serria, it has been in the garage 4 times for #2&7 fuel injectors.The fourth time they said #2&7 injector are not working right. I had my nephew who was a gm mech. change them and this is after i had the truck at the garage 4678 mile before this with plugged inectors they plugged up again after they cleaned the tank and the fuel rails, they keep saying it is bad gas well this last time that my nephew pulled the injectors they was full of rust .I was told by someone that this is caused by by the fuelines and the crossover pipe.They are made of low carbon steel. and they rust internaley because they are not coated. Is there any one else having this same problem with thier truck and if so what did you do to correct the problem I have talk to gm and they say that it is bad gas. and they have never had any problem with the 2004 serria for this problem Bill

Mr. Smith · January 11, 2006

I have a 2004 serria, it has been in the garage 4 times for #2&7 fuel injectors.The fourth time they said #2&7 injector are not working right. I had my nephew who was a gm mech. change them and this is after i had the truck at the garage 4678 mile before this with plugged inectors they plugged up again after they cleaned the tank and the fuel rails, they keep saying it is bad gas well this last time that my nephew pulled the injectors they was full of rust .I was told by someone that this is caused by by the fuelines and the crossover pipe.They are made of low carbon steel. and they rust internaley because they are not coated. Is there any one else having this same problem with thier truck and if so what did you do to correct the problem I have talk to gm and they say that it is bad gas. and they have never had any problem with the 2004 serria for this problem Bill

<{POST_SNAPBACK}>

If you look you will find this was discussed here or in the regular forum for your truck within the past couple days.

GM-Tech · January 12, 2006

Excessive amounts of water in the fuel is the cause of this. You have two options. Just keep taking the problem injectors out and cleaning out the packed in rust or replace all the metal lines, including the fuel rails. No amount of flushing the lines will get rid of this stuff.

I believe the fuel traveling through the lines eventually scrubs off the rust particles because we've worked on these, replacing injectors for the problem and not replacing the lines, and they haven't come back. Perhaps they went elsewhere when it reoccured?

It's not a 2004 Sierra problem. It's a problem that can affect any fuel injected vehicle that gets water in the fuel.

truck04 · January 12, 2006

I know I may be getting water in my gas, But when I take it to my gmc dealer they say that I am getting settlement in my gas and it is getting by the filters in tank in one breath then the next they say that they don't know where it is coming from and want to charge me more time and money to find out where it is coming from. they have not had this problem with this truck and don't know what to do but try and find the problem this truck has been to them 4 times since may 05 i found this piece on the web about 2004 >>>>> Increasingly stringent evaporative emission regulations have caused GM to introduce returnless fuel systems. In a returnless design, no fuel is sent back to the fuel tank from the engine. All fuel leaving the tank flows through the fuel injectors.

Returnless systems have been in production since 1998 (Trans Am, Camaro and Corvette). A significant migration toward returnless fuel systems began in the 2004 model year. By 2007, the majority of GM vehicles will be converted to the returnless design.

Any contamination (including rust) that is built into or forms in the fuel line will find its way to the fuel injectors. A filter at the inlet to the fuel injector filters out small contaminants, including rust (fig. 11). If enough debris accumulates on the injector filter, it will start to restrict flow. This will have a negative effect on performance and driveabilty.

For the 2004 model year, there has been an increase in the number of injectors returned with rust in the injector filter. The rust appears to be coming from several sources:

- the chassis fuel line

- the crossover pipe on the Gen III fuel rail.

Both pipes are made of low-carbon steel, and the inside of the pipe is not coated. If water gets into the fuel system, it has the potential to rust the line.

When diagnosing driveability symptoms due to clogged fuel injectors, follow the procedures outlined in bulletin 03-06-04-030A. If the bulletin procedures lead to replacing an injector, inspect the removed injector for evidence of rust contamination. If rust is plugging the fuel injector, replace it, because a procedure for removing rust from the injector filter has not been developed.

If rust remains in the fuel line, there is a chance that the injector filter will plug up again. Whenever rust is observed in an injector, flush the fuel lines. If the fuel line cannot be completely flushed of rust, replace it.

A small amount of rust in the fuel tank will typically not cause a problem. The fuel filter will prevent the rust from getting to the injectors. The capacity of the filter is large enough to keep it from plugging up. There is also a strainer (“sock”) at the inlet to the fuel pump. The strainer prevents contamination from getting into the fuel pump and causing problems. However, rust in the fuel tank is a sign that water may be in the tank. If rust is observed in the fuel tank, empty it and flush with hot water, according to SI procedures.>>>>>> But they don,t know anything about it and like i said they want to keep charging me to have the problem fixed but they have not found the problem yet and they say it is just the bad that i am getting.

GM-Tech · January 12, 2006

The problem is not in the tank. As that document says, it wouldn't get past the fuel filter.

Even though you may no longer have water contamination, once the rust forms in the lines and rail, it's going to deposit in the injectors (particularly #7) until it's all gone.