2xLS1

iTrader: (25)

I fixed an 04 Escalade 5.3L last week that was setting a P0101 MAF Perf, P0171 P0174 lean codes, and a P0175 rich code all at the same time. LTFTs at idle were -12 to -15% and increasing the rpms without the vehicle moving the LTFTs would go to +15%. I didn't drive the vehicle while scanning, just raised the RPMs in Park. The customer also complained about very rough running when cold. What I found was the rubber coupler between the K&N intake tube and the throttle body had slipped off the throttle body. Didn't make sense why that caused the - fuel trims at idle but it did. This was a completely stock vehicle on a stock tune.

DrHoho02

My 06 5.3l Tahoe did the same thing. I asked here, no response and no ideas. What it turned out to be was the vehicle being E85. In Connecticut we have no E85 and the truck was bought used, not knowing the history of fuel purchase. The alcohol content reading was off in the ECM, you may want to check this. After being reset the LTFT were back to normal, GM has the software update for this. Here is some info that helped me.

Subject: Use of E85 Fuels in Vehicles Not Certified by GM as being FlexFuel Compatible/Aftermarket Conversion of Vehicles to Operate on E85 Fuels #06-06-04-035A - (02/05/2008)



Models: 2008 and Prior GM Passenger Cars and Trucks NOT FlexFuel (E85) Compatible (including Saturn)

2008 and Prior HUMMER H2, H3

2005-2008 Saab 9-7X




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This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 06-06-04-035 (Section 06 -- Engine/Propulsion System).


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Aftermarket Conversions of Vehicles to Use E85 Fuels
General Motors has become aware of several companies that claim to be able to convert vehicles equipped with gasoline engines to be compatible with E85 Fuels.

• Vehicles certified by GM as being FlexFuel (E85) compatible contain numerous calibration and component differences that are not conducive to an aftermarket retrofit.

• General Motors DOES NOT support or endorse conversions that may alter the emissions and related emissions components of its vehicles.

• Repairs that may result from changes to GM built components, and repairs that result from the use of improper fuel, such as the use of gasoline containing more than 10% Ethanol in a non-FlexFuel certified vehicle, are not covered under the terms of the New Vehicle Warranty.

E85 Compatible Vehicles
The only E85 compatible vehicles produced by General Motors are:

• 2000-2002 S-Series pickups with 2.2L (VIN 5- RPO L43)

• 2002-2005 full-size pickups and utilities with 5.3L (VIN Z -- L59)

• 2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe with 5.3L (VIN Z -- RPO L59)

• 2006 Chevrolet Impala, Monte Carlo with 3.5L (VIN K -- RPO LZE)

• 2006 GMC Sierra, Yukon, Yukon XL with 5.3L (VIN Z -- RPO L59)

• 2007 Chevrolet Express with 5.3L (VIN Z -- RPO L59)

• 2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

• 2007 GMC Savana with 5.3L (VIN Z -- RPO L59)

• 2007 GMC Sierra, Yukon, Yukon XL with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

• 2007 Chevrolet Impala, Monte Carlo with 3.5L (VIN K -- RPO LZE)

• 2007 Saturn Relay, Buick Terraza, Chevrolet Uplander, Pontiac Montana SV6 (Canada Only) with 3.9L (VIN W -- RPO LGD)

• 2008 Chevrolet Impala with 3.5L (VIN K -- RPO LZE) and 3.9L (VIN 1- RPO LZG)

• 2008 Pontiac Montana SV6, Chevrolet Uplander 3.9L (VIN W -- RPO LGD)

• 2008 Chevrolet Express, GMC Savana with 5.3L (VIN 4 -- RPO LMF)

• 2008 Chevrolet Avalanche, Suburban, Silverado, GMC Yukon, Sierra with 5.3L (VIN 3 -- RPO LC9)

• 2008 Chevrolet Avalanche, Suburban, Silverado, Tahoe, GMC Yukon, Yukon XL, Sierra with 5.3L (VIN 0 -- RPO LMG)



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Subject: Information on 3.5L (VIN K - RPO LZE), 3.9L (VIN W - RPO LGD) and 5.3L (VINS Z, 0, 3 - RPOs L59, LMG, LC9) E85 Fuel Compatible Vehicles - Alcohol Content, Switching Between Gasoline and E85 Fuel #06-06-04-010E - (07/25/2007)



Models: 2007 Buick Terraza

2006-2007 Chevrolet Avalanche, Impala, Monte Carlo, Silverado, Suburban, Tahoe

2007 Chevrolet Express, Silverado Classic, Uplander

2006-2007 GMC Sierra, Yukon, Yukon XL

2007 GMC Savana, Sierra Classic

2007 Pontiac Montana SV6 (Canada Only)

2007 Saturn Relay

with 3.5L, 3.9L or 5.3L E85 Compatible Engine (VINs K, W, Z, 0, 3 - RPOs ZLE, LGD, L59, LMG, LC9)




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This bulletin is being revised to announce the release of calibrations for the 2007 full-size vans and classic trucks. Bulletin content and warranty information has also been updated to reflect this change. Please discard Corporate Bulletin Number 06-06-04-010D (Section 06 -- Engine/Propulsion System).


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For 2006, GM has changed the method of "sensing" the alcohol content of fuel in E85 compatible vehicles.

Important: Only vehicles designated as E85 compatible are capable of operating on fuel with greater than 10% ethanol content. See Service Bulletin Number 05-06-04-035.

For 2006 and 2007 models, E85 compatible vehicles marketed in North America no longer use an alcohol sensor to determine and adjust for the alcohol content of the fuel in the tank. Instead, the vehicle "learns" (calculates) the alcohol content of the fuel, (and subsequent mixture in the fuel tank), through a series of measured adjustments.

A minimum of 11 Liters (3 gallons) must be put in the tank in order for the vehicle to identify/recognize a "re-fueling event." It is necessary to turn the ignition "off" in order to have the re-fueling event recognized; however local safety regulations should be followed.

Important: The system is initialized by baselining itself on ASTM spec Gasoline (alcohol 0-10%). When an E85 compatible vehicle is built, an ECM or PCM replaced, or if the learned alcohol content has been reset with a scan tool, the fuel system will need to contain ASTM spec gasoline with 10% or less ethanol content. If the fuel in the fuel system needs to be drained and replaced with ASTM spec gasoline, the vehicle will need to run for approximately 11 km (7 mi) at full operating temperature before the system will be fully adjusted to the correct alcohol content. Once system initialization has been completed and the calibration verified to be the below listed calibration part number or later, gasoline with any ethanol content between 0 and 85% may be added, provided it is added in a quantity of 11 Liters (3 gallons) or more, and the vehicle is run long enough to learn the new fuel (see below).

Adjustments
After the re-fueling event, the system registers the amount of fuel that was taken on-board, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines the ethanol content of the fuel that was added. Based on that determination, it adjusts itself to the expected alcohol mix in the fuel tank and lets the fuel trim and O2 sensor activity fine tune the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or vice versa, can result in driveability symptoms due to the inability of the system to adjust for fuel composition (by not attaining the parameters necessary to reach closed loop operation).

Important: GM has released revised calibrations for 2006 and 2007 model FlexFuel (E85 compatible) vehicles that will accept the introduction of gasoline/ethanol blended fuels with ANY ethanol concentration that falls between 0 and 85%.

sroka

iTrader: (12)

Changed the plugs a few days ago, gapped at .045 didnt help any. I'm about to go buy one new 02 and see if that helps any.