| Subject: | Fuel Injector Replacement Information - Inspect Fuel Injector Inlet Filter Screen for Rust |
| Models: | 2005-2007 Buick Rainier |
| 2004-2007 Cadillac Escalade, Escalade ESV, Escalade EXT |
| 2004-2007 Chevrolet Express, Silverado, Suburban, Tahoe |
| 2004-2007 Chevrolet Trailblazer |
| 2004-2007 GMC Envoy, Envoy XUV |
| 2004-2007 GMC Savana, Sierra, Sierra Denali |
| 2004-2007 GMC Yukon, Yukon XL and Yukon Denali XL |
| (RPOs L33, LH6, L59, LM7, LQ4, LQ9, or LR4) |
This PI was superseded to update models and condense the recommendations. Please discard PIP3280C.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some customers may complaint of a SES light, engine misfire, or other engine performance concerns. In some instances, their concern may be the result of a plugged fuel injector inlet filter screen, which may not be repaired by cleaning the fuel injectors
as outlined in 03-06-04-030.
In a returnless fuel system, all fuel leaving the tank flows through the fuel injectors because there is not a return line for fuel to return to the fuel tank from the engine. As a result, any contamination (including rust) that forms in the fuel line
will find its way to the fuel injectors. The fuel injector inlet has a filter screen to filter out small contaminants, such as rust. If enough debris accumulates on the fuel injector inlet filter screen, it will start to restrict fuel flow.
Recommendation/Instructions:
If the latest version of 03-06-04-030 leads to fuel injector replacement, inspect the fuel injector inlet filter screen for rust contamination. If rust contamination is present, replace the affected fuel injector. Replacement of all steel fuel lines is
also recommended whenever rust is observed in an injector because there is a chance that rust remains in the steel fuel lines.
Also inspect for rust in the fuel tank, which indicates that water may be present. If present, it could affect uncoated portions of the fuel pump and filter assembly and the fuel lines, and could lead to a re-occurrence. If rust is observed in the fuel
tank, follow the Fuel System Cleaning Procedure in SI to clean the inside of the fuel tank and refill with clean fuel. Also inspect the in-tank fuel pump module and filter assembly, and replace as necessary.
Using GM Fuel System Treatment PLUS (at oil change intervals) can protect against the affects of water and certain contaminants that may be present in some poor quality fuels.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
