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Premium Member
TrailblazerSS
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1,569 Posts
Discussion Starter #1
I got an intermittent p0121 code over the course of 6 months or so. I have multiple throttle bodies laying around and decided to put on what I thought was a stock tb instead of cleaning my stocker. It was off of my 12 sierra denali when I upgraded it to an ls3 tb. I pulled it out thinking it was identical and quickly realized it was slightly different. I went ahead and put it on but the idle in park and neutral surged up to 2000 rpm and wouldn't idle down even after driving it for a week to week and a half. I found the thread about the difference in throttle bodies so I changed the etc scalar in hpt to what my stock denali tune was as well as the percent max and percent max-brake to the 12 denali stock values (this happens to be the same as 09 tbss's). The idle was slightly better but i would have to stop in gear before putting it in park for around 10-12 seconds before the truck would suddenly idle down 2-300 rpm then I could put in park without it idling up. I decided to see if a gold blade ls3 would react any differently. I changed the etc scalar and percent max/percent max-brake to the stock camaro values and swapped tb's. This helped a little but it still had the same issues as the 09 up truck tb. Fast forward to today I cleaned my stock tb and of course it runs perfect even with the camaro values still in the tune. I will re flash it with the stock values but it runs perfect. I guess my question is gm obviously upgraded the tb's in 09 for a reason and assuming they are better in some way, why do they react so weird with the 08-older operating systems and what else needs to be changed to get say a gold blade ls3 to work with an 07 os? And yes I have read old threads all the way back to 09 on here and hptuners and they all just either say it worked great, or don't do it because it will never work right. But most just say etc scalar is all that needs to be changed. Well that doesn't work with mine for some reason. The G8 guys have similar issues since the platform ran over that 08/09 model year. Alvin and Kelly had no problem tuning my sierra denali with an ls3 tb but told me they feel the stock tb is the best with our trucks unless you go FI or some radical setup, so what's different? Is it the opening rate of the plate that causes the weird idle? Why do some tuners say it will work great and other say its total waste. Why do some of our trucks have zero issues and other literally can't get them to work? And I know this has been covered to death as far as if it will or won't work but I couldn't find any of the reasons why.
 

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TT AWD TBSS Jeep
TT AWD SS Pwrd Jeep
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5,825 Posts
Some TB are just PITA how they work and respond to the ECM. There are airflow limits based on TPS and RPM that can be tweeked along with VE and MAF. It should be able to work, but that said, I have even seen Matt recomend not using certain color blade TBs with certain ECM combos.
 

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Premium Member
2007 TBSS AWD
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31,502 Posts
For an 07 TBSS you want to use either a stock tb or a silver blade LS2/7 TB with a value of 4725.

The newer TBs do not work as well on the older TBSS OS/ ECMs. You can make a newer one work at first but they tend to develop problems over time which is why some people will say they work fine, because the sample size of 1 they are dealing with means they are now an expert. lol

Because I do so many, I will not recommend this because when you tune a lot of vehicles "no news is good news". Intermittent throttle issues and codes caused by improper hardware will eat up time I can avoid by recommending the correct parts.
 

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Premium Member
07 TBSS RWD
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1,795 Posts
For an 07 TBSS you want to use either a stock tb or a silver blade LS2/7 TB with a value of 4725
Thanks that saves me from having to hunt down that value or ask you now :coolthumb:
 

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Premium Member
07 TrailblazerSS AWD
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2,305 Posts
Interesting but old and contains some misleading info. People were a bit confused when the DBW 102s first came out.
No doubt. But for those looking at using stock stuff it seems applicable. This was the result of a 10 second Googling... aka. the best way to tune.
 

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Premium Member
TrailblazerSS
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1,569 Posts
Discussion Starter #11
I guess my confusion was from thinking it was just the difference in the size of the tb's that were causing people's issues. But it sounds like that has very little to do with it. It's the processor in the tb or the difference in the newer OS or a combination of both. I really just wanted to use my 09+ truck tb since I had it sitting around and thought it was the same part number but after researching found out it wasn't and then started to read more about all of the differences in the GM throttle body's. I noticed the difference in ETC scalar in the tunes and figured a quick change to those values would allow it to work fine but I was obviously wrong. With that said I am still having issues with the truck. I cleaned the stock tb with crc tb cleaner with the tb off of the truck. I let it dry overnight, changed the etc scalar back to the original values and installed the tb. I had the negative terminal off just in case. Even with the stock tb the truck still acts the exact same as it did with both of the newer throttle body's. It acts like it's on cruise control running down the highway and if I don't wait for 5-10 seconds before putting it into park the truck idles up to 1500rpm and won't idle down. If I wait the 5-10 seconds it goes from 1000rpm at a stop to around 800rpm's then I can put it into park and it's fine. Nothing else has changed and I've given it 4 days of driving to relearn with the clean throttle body. I am going to clean the MAF just to make sure that's not an issue but it looks perfectly fine. I've even put on the stock cai to make 100% sure that the maf is clocked correctly. It still runs the same. But the truck ran perfectly fine before I removed the stock throttle body, and only intermittently would the p0121 code pop up so I highly doubt it's the MAF.
 

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Premium Member
2007 TBSS AWD
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31,502 Posts
I guess my confusion was from thinking it was just the difference in the size of the tb's that were causing people's issues. But it sounds like that has very little to do with it. It's the processor in the tb or the difference in the newer OS or a combination of both. I really just wanted to use my 09+ truck tb since I had it sitting around and thought it was the same part number but after researching found out it wasn't and then started to read more about all of the differences in the GM throttle body's. I noticed the difference in ETC scalar in the tunes and figured a quick change to those values would allow it to work fine but I was obviously wrong. With that said I am still having issues with the truck. I cleaned the stock tb with crc tb cleaner with the tb off of the truck. I let it dry overnight, changed the etc scalar back to the original values and installed the tb. I had the negative terminal off just in case. Even with the stock tb the truck still acts the exact same as it did with both of the newer throttle body's. It acts like it's on cruise control running down the highway and if I don't wait for 5-10 seconds before putting it into park the truck idles up to 1500rpm and won't idle down. If I wait the 5-10 seconds it goes from 1000rpm at a stop to around 800rpm's then I can put it into park and it's fine. Nothing else has changed and I've given it 4 days of driving to relearn with the clean throttle body. I am going to clean the MAF just to make sure that's not an issue but it looks perfectly fine. I've even put on the stock cai to make 100% sure that the maf is clocked correctly. It still runs the same. But the truck ran perfectly fine before I removed the stock throttle body, and only intermittently would the p0121 code pop up so I highly doubt it's the MAF.
In your case it is electronic incompatibility and not the scalar.

In the case of something like a CTSV or ZR1 that were both 09+ only and came with an 87mm TB, then changing to an LS3/7 gold blade would just simply be a scalar change.
 
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