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TheDTK

Newer ECU Replacement for efficiency gains possible?

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I was wondering if it would be possible to improve fuel economy among other things by just replacing the factory ECM with one of a newer truck. I have a 2003 Silverado 6.0 RWD and a 2006 GMC 6.0 RWD and the 2006 gets much better Fuel economy

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The 2006 probably has AFM which provides better mpg with a trade-off of higher complexity and increased repairs cost. Search for AFM Delete and you'll see discussions of the problems.

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'06 (basically, all the GMT800 trucks) didn't have AFM.  it started with the newer body style.

 

are both trucks 1500's?

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Both trucks are 2500HD’s

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7 hours ago, davester said:

'06 (basically, all the GMT800 trucks) didn't have AFM.  it started with the newer body style.

 

are both trucks 1500's?

Both trucks are 2500HD

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Between 2003 and 2006 they should be running comparable PCMs. The only real difference would be if one or the other can only support drive by wire. Other than that it should just be tuning differences. 

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Both 2003 and 2006 are drive by wire in those trucks.

 

Both are almost the exact same calibrations in them. Sure minor stuff as newer calibrations get updates but the overall model for fueling and airflow settings are basically all the same.

 

I'd suspect some sort of issue with the 2003 truck if the mileage is that much worse. I'd want data logs of both trucks to see how they vary.

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On 5/14/2019 at 9:14 PM, CamGTP said:

Both 2003 and 2006 are drive by wire in those trucks.

 

Both are almost the exact same calibrations in them. Sure minor stuff as newer calibrations get updates but the overall model for fueling and airflow settings are basically all the same.

 

I'd suspect some sort of issue with the 2003 truck if the mileage is that much worse. I'd want data logs of both trucks to see how they vary.

I was only referring to the possibility that one or both PCM's may be able to support DBC. 

 

Another possibility is that the rear axle ratio's are different, or there is a problem in the transmission. My 02 had a bad VSS and was bouncing the speedometer around, not enough to show on the dash, but on the scanner it was all over the place. The torque converter would never lock up and my gas mileage sucked. 

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On 5/14/2019 at 11:14 PM, CamGTP said:

Both 2003 and 2006 are drive by wire in those trucks.

 

Both are almost the exact same calibrations in them. Sure minor stuff as newer calibrations get updates but the overall model for fueling and airflow settings are basically all the same.

 

I'd suspect some sort of issue with the 2003 truck if the mileage is that much worse. I'd want data logs of both trucks to see how they vary.

Both trucks have a 4:10 axle ratio and have had the same individual gas mileages since day 1 and the obvious difference is that my 2006 is a 6 speed, but it’s also 4x4! Under light throttle the 03’s throttle is moderately unresponsive compared to the 06 so I suspect the calibrations are a little more improved and complicated than my 2003 and maybe even a different camshaft was used in newer applications? AFM? I’m not sure at all I just know they are noticeably different drives. And both of my trucks are indeed dbw and in fact I installed a 2006 throttle body assembly thinking it would be more responsive, I was wrong. Ive kept up maintenance myself well before it was due and both have had several parts replaced at one time or another the 03 has 177k miles the 06 240k and both run the exact same as when I bought them. My babies <3. oh and both trucks are almost even in a drag race just thought I should add that lol.. I’m complaining about a 7mpg difference btw it might just be the tranny but I find that to be a helluva lot of savings from a transmission.

9 hours ago, Markmx6 said:

I was only referring to the possibility that one or both PCM's may be able to support DBC. 

 

Another possibility is that the rear axle ratio's are different, or there is a problem in the transmission. My 02 had a bad VSS and was bouncing the speedometer around, not enough to show on the dash, but on the scanner it was all over the place. The torque converter would never lock up and my gas mileage sucked. 

I have slight issues between 3rd and 4th but it’s very minor. And I trust that Lucas I threw in there xD

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19 minutes ago, TheDTK said:

...my 2006 is a 6 speed, but it’s also 4x4!

Duramax with the Allison transmission?  No factory six speeds in GMT800s in 2006 behind gas motors.

 

6.0 gas motor was the LQ4 and LQ9.  You would have the LQ4 in both trucks.  Cams are the same but I am curious if there might be differences in the exhaust (improved bends) and in programming for starters.  

 

 

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13 hours ago, swathdiver said:

Duramax with the Allison transmission?  No factory six speeds in GMT800s in 2006 behind gas motors.

 

6.0 gas motor was the LQ4 and LQ9.  You would have the LQ4 in both trucks.  Cams are the same but I am curious if there might be differences in the exhaust (improved bends) and in programming for starters.  

 

 

Definitely not a Duramax, it is a 6.0. Well that’s disappointing to hear. So that makes me think there is a huge difference between the 2 then. Looking at both engine bays you would think they’re identical.

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11 hours ago, davester said:

Actually, I believe the 8.1L GMT800 gassers got the Allison as well.

You're right, forgot about that!  Thanks!

30 minutes ago, TheDTK said:

Definitely not a Duramax, it is a 6.0. Well that’s disappointing to hear. So that makes me think there is a huge difference between the 2 then. Looking at both engine bays you would think they’re identical.

 

They are and there's not much difference between them.  If you want to get them to perform better, get them tuned.

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