Gadgetized

iTrader: (9)

So I am not sure what is happening. If I drive down the road with my heater/blower motor on my ignition timing fluctuates. It will lower 30 degrees when cruising down the road. If I turn off my blower motor, it is perfectly fine. Has anyone ran into this before. I can post a log if someone has never ran into it before.

BlackGMC

iTrader: (31)

Was your defrost on? If so the truck uses the ac compressor with the defroster. The tune can pull timing for the ac clutch engagment.

Gadgetized

iTrader: (9)

No, no defroster, no ac.

DrX

iTrader: (7)

I was having a similar issue as well last year. Maybe I still am, but I don't remember because I have been waiting so long for a new 80E. With the AC on, the timing would alternate between what it was set at in the tune and 18* lower. It constantly cycled between 5 seconds of normal timing and 5 seconds of severely retarded timing when cruising. Very annoying. I logged all of the spark PIDs including AC compensation spark and nothing showed up. Nothing in the tune seemed to have any effect either. I also had strange things going on with the injector duty cycles and dynamic airflow. Those went away went I swapped out the Roadrunner for the stock PCM.

This is on a EFILive custom OS

Gadgetized

iTrader: (9)

Hmm. I have a COS too. I can't think of any other PID's to log that would show anything.

DrX

iTrader: (7)

I dug up a log from last year that shows what was going on.

1FastBrick

iTrader: (17)

Are you guys aware that there is an issue with the Blower motor resistor's and the plug. There is a TSB saying you need to get a new style resistor and update the plug/harness. The TSB states it could short out and cause a fire.

Not sure if this is whats causing this issue but 1 guy had his truck burn down on another forum recently and they suspect this might be what caused it. There are also other documented cases if you search the net.

If its shorting it might be causing other electrical issues.



G.M. SERVICE BULLETIN
Special Coverage Adjustment
Bulletin No.: 11046

Date: April 07, 2011

Subject: 11046*****SPECIAL COVERAGE ADJUSTMENT*****Heating, Ventilation, and Air Conditioning Blower Not Fully Functional on All Blower Speeds, Inoperative, or Runs Continuously with the IGNITION OFF.

Models:
2003-2006 Chevrolet Avalanche, Suburban, Tahoe
2003-2007 Chevrolet Silverado
2003-2006 GMC Yukon, Yukon XL
2003-2007 GMC Sierra
Equipped with Manual HVAC (CJ3) or Heavy Duty Heater (C42)

Due to part availability, owner letters will be released in phases starting with older model year first. Owners for model year vehicles not included in first phase owner mailing will receive an owner advisory letter.

The letter will inform the customer that parts are not yet available and that another letter will be sent to them when parts become available. A copy of this letter will be attached to the dealer message announcing this bulletin.

In the meantime, if a customer brings their vehicle to the dealership with the condition described in this bulletin, repair the vehicle using the parts called out in this bulletin.

Condition.......On some 2003-2006 model year Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 model year Chevrolet Silverado and GMC Sierra vehicles equipped with a manual heating, ventilation, and air conditioning (HVAC) system (CJ3) or heavy duty heater (C42), the interface between the electrical terminals of the relay Resistor Module and the Wiring Connector that powers the module may be incapable of conducting higher current levels for sustained periods of blower motor operation. In addition, moisture and other contaminants may enter the fresh air intake plenum and contact the internal circuit of the module or corrode the terminals. Either of the above may cause the relay resistor module or wiring connector to overheat, resulting in one or more of the following symptoms:

- The HVAC blower may not function on certain or all blower speed settings
- A burning plastic smell or smoke may be present in the vehicle
- The HVAC blower may run continually with the ignition in the OFF position


IN VERY RARE events, if the above Symptoms are Ignored......A FIRE Could Occur.


*****SPECIAL COVERAGE ADJUSTMENT*****This special coverage covers the condition described above for a period of ****10 YEARS or 150,000 MILES(240,000km)****whichever occurs first, from the Date the Vehicle was Originally Placed into Service.......Regardless of Ownership.

Dealer's are to install a New Blower Module Connector......and the Repair will be made at No Charge to the Customer

Important.......For vehicles covered by Vehicle Service Contracts, All eligible Claims with repair orders on or after April 8 2001 are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with Repair orders prior to April 8 2011 must be Sumitted to the Service Contract provider.

Vehicles Involved,
Involved are certain 2003-2006 model year Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 Model year Chevrolet Silverado and GMC Sierra Vehicles equipped with a Manual HVAV (CJ3) or Heavy Duty Heater (C42)

Improtant,
Dealers are to confirm vehicle eligibility prior to beginning repairs by using the Applicable Warranties section in the Global Warranty Management system.

Gadgetized

iTrader: (9)

Good info to know right there. I will check into it tomorrow. I don't think that is my problem though, my heater shuts off fine, and seems to be working properly. I emailed Justin, and he said it is normal. He said that the AC pump will periodically kick on to remove moisture from the system. If I manually kick on the AC pump, I don't get that problem though. I can't see GM programming something like this into a tune. I have never felt a vehicle do this before. Today I was driving and the timing went from 42 to 5 degrees. The truck falls on its face. It slows down like you are pulling the shifter into drive.