So I have a 2000 silverado that's turbocharged and it's tuned of hp tuners. Just curious why can I only push it to 14 pounds of boost? I've taken it to a few tuners and they have all told me the same thing that my operating system can only support 14 pounds. I'm on a gm 3 bar map sensor from the ctsv but the way they explained it is that it's basically all my stock ecu can support

 

sounds like a bunch of malarkey. Is your engine built or is everything else stock? Most tuners will only tune your setup to what they deem “safe”. Their reputation is behind their work so if anything breaks they can claim deniability. Just my opinion, I could be way off on this one.

 

Did you change out your map sensor?

 

it's not related to if the engine can handle, they both told me the same thing that my ecu couldn't go past 14 pounds. Basically if i went over 14 pounds it would lean out and over boost because my operating system cant go over that limit. One of the tuners buddies suggested i get a ecu from a gto.

 

https://thetuningschool.com/blogs/ne...ons-of-gm-ecms

 

GM used a lot of different PCM's in the 99-07 truck platforms, 02 and older the PCM's only had 512KB of storage, while the 2003+ had 1MB. The smaller file size of the early PCM's limited a lot of the early OS's in the trucks to 2 bar. With the stock OS in my 2001 (P01 ECU) I could only run 2 bar. I flashed my stock ECU with a flex fuel Tahoe OS (with some segment swapping to run my 4L80E since Tahoe's didn't get those) to get 2 bar flex fuel. You can run your truck off other OS's or later ECU's with some work. I just opened a 2003 Silverado file I grabbed from the internet and it shows an option for 3 bar, but it requires the newer PCM to work and you have to use a DBC ECU so it can control your IAC like out of the vans. I think you have to swap around a few pins on the ECU connector as well since the 2003+ are pinned a little differently than the 99-2002's.

Do you have emissions inspection in your area? If you swap to a later ECU to get 3 bar, will having a different VIN number in the ECU be an issue for the emissions inspection?

 

Well, you about covered it brother. I guess I was a tad vague. Lol.

 

emissions inspections arent a concern for me, i can get around that. My truck has already been flashed, it's on e85 so we did the flex fuel sensor with the Tahoe file. It's already on a 3 bar CTS-V map sensor. What your saying about the 512kb is the same thing they both told me and that's what limiting me from turning up thr boost over 14 pounds. They said it over boost and leans out because the ecu cant recognize whats going on past that limit

 

3 bar CTS-V

 

If you want flex fuel and 3 bar, the easiest path is to find an ECU from a 2003+ Drive by Cable (DBC) express van, swap around the few pins that are different in the ecu connectors and have it tuned. Talk to your tuner about it. The other option is to go to an aftermarket ECU.