I have seen several people mention they have used the OS from a 2002 Tahoe on a gm f-body to enable flex fuel options. I have a tune file from a 2002 Tahoe, but am not sure of the procedure to write the OS. Do I just write entire, use a license, and then write my calibration over the top?
Yep just perform a Write entire
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Loaded OS with my tune overwritten, disabled flex fuel under fuel>>Flex Fuel>>General. I have e85 in it running 9.79 stoic on current tune, so on new os I changed the stoic afr values to 9.79 for all just to run the proper value till i get the alcohol sensor installed. Would there be any other changes I would need to make to run the new OS with flex fuel disabled til I get the sensor wired in?Originally Posted by Ben Charles
Anyone?
You can run either your original OS or the Tahoe Flex Fuel OS if you're going to run E85 exclusively.
If you run the Tahoe Fuel OS without the sensor, then just delete the sensor DTC's and change stoic to 9.79 and change the Flex Fuel Spark table as needed.
Thanks! I changed the Stoic afr values across the chart, I did get a light, but swapped the tune back before reading the code, so the the light was probably from the sensor not being hooked up. Ill give it another try.
The flex Fuel spark table will only come into play when the sensor detects alcohol, correct, so leaving alone should not have any affect if I change the stoic across the board to what I am running, which is E85?
Thanks for the reply.
I reloaded the Tahoe OS, set P0177 and P0177 to no error reported, same with p1638 Gen F Terminal which I assume I dont have. Oil change, service vehicle and airbag light are on. Reset oil, may have been a coincidence, but other 2 stayed on, and there are no codes in HP tuners when I read them. I flashed the old OS back and lights are correct. Is this because the vin number is not correct as it still has the Tahoe vin? I tried to change it but it says my vin is invalid. Any way to correct this?
So is there no way to run the Tahoe OS on the FBody without having airbag and service vehicle lights on?
There isn't a straight-forward way to do it. You can use some User Defined Parameters and add the proper flex fuel tables to the F-body OS, but it takes some knowledge of which tables to add. You might contact James Short at Shortuning. He can populate those parameters for you if you'd like to use the F-body OS.
What BCM/IPC/SIR(SDM) codes do you have after the change? Some of that stuff will freak out after even a straight like-for-like stock PCM replacement/reprogramming and need to be reset.
I dont have anything to read the bcm with. I am going to have it dyno'd once its broken in, ill see what my tuner can do.
is it possible to run the alcohol sensor as well if it was never part of the os originally?
Yes. It is possible with the use of User Defined Parameters and knowing which tables to add.
No
User defined parameters isn't custom parameters. It is parameters already in place by GM in which are mapped out by the end user. If you rewrote some of the code you could then use this to access the memory locations of the modified OS but that won't usually work since rewriting OS's will skew other parameters in the calibration.
The Tahoe OS is the only OS capable on a P01 PCM to enable flex fuel. A lot of the table modeling in that OS is adapted over into the P59 PCM's as well. There are a TON of tables not accessible in HPT currently that would make fine tuning a performance application on this OS nice. I have mapped out quite a few parameters as well as manually applied a 4L80E trans segment to that OS so it could be used in Fbodies. I'm currently trying to spoof the 2bar OS into thinking it's a 3bar so we can use it with 3bar MAP and have fuel control up to 3bar.
James Short - [email protected]
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2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
So would a p59 pcm need the tahoe OS to run flex fuel? Was considering swapping due to larger memory, would it be worth the cost?
Yes it would...a newer Tahoe cal.
A P59 was never available with an F-body calibration.
so a p59 will run flex fuel os1252063?
want to upgrade to flex fuel.. going to modded 60.L and done need thisn thign runnign lean on dang 10-10% mix or whatever i can get to shove in it..
pupms n sensors ont he way want to get it sorted BEFORE the new mnotor goes in..
been told that OS wont take flex fuel input but the tune show enable or disable flex but no additals table sshow up to tune???
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