Gen III Flex fuel Write-up
12-12-2016, 09:08 PM
#41
No, you do not have to do a segment swap but its only added to OS 12216125 which uses the P01 PCM. You do have to upgrade to the newest version of Hptuners to have access. The Blend Factor table is also on two P59 OS too IIRC.
12-13-2016, 08:54 AM
#42
Could you share what P59 OS those tables have appeared on?
12-13-2016, 09:37 AM
#43
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,837 Likes
on
1,145 Posts
This thread would be a great one to bookmark. A wealth of knowledge in here, and its a topic you don't see every day
12-13-2016, 10:03 PM
#44
Here you go:
2004 GTO 12586243 OS
2003 - 2005 Avalanche 12589462 OS
I'm not positive on the OS's cause I'm at work but I do have them on my laptop at home. The Avalanche OS is DBW and the GTO is DBC IIRC.
Both of these Flex Fuel files are in the Hptuners respiratory so you can look there to see if I gave the correct OS info.
2004 GTO 12586243 OS
2003 - 2005 Avalanche 12589462 OS
I'm not positive on the OS's cause I'm at work but I do have them on my laptop at home. The Avalanche OS is DBW and the GTO is DBC IIRC.
Both of these Flex Fuel files are in the Hptuners respiratory so you can look there to see if I gave the correct OS info.
Last edited by Monte4ever; 12-13-2016 at 10:58 PM.
The following users liked this post:
fastsspr (10-05-2020)
12-20-2016, 04:06 PM
#47
On perfect. If anyone on the Houston area had one please let me know. I'd really like to have it by the weekend. My dad will be in town from California and he was really looking forward to going for a ride and now I have a bricked pcm so please send a pm of you have one.
12-21-2016, 12:28 PM
#51
It's awesome everybody is starting to get this worked out. I ordered my p59 from a pcm dealer and he is sending it out with the proper OS and mapped for my car. Can't wait to see how it does. I don't kneed AC or gas gauge for mine so it's a little simpler.
So I'm curious if anyone knows about this but according to this pcm dealer GM started using a virtual flex fuel sensor after 06 I believe. I may be wrong on the year. Does anyone know how this "virtual" sensor works? The pcm dealer I'm working with wants me to get everything working using an actual sensor and then we are going to try the virtual setup for fun. His thoughts are if he can get the virtual sensor to work for customers he could literally make a plug n play setup for 99-02 harness.
So I'm curious if anyone knows about this but according to this pcm dealer GM started using a virtual flex fuel sensor after 06 I believe. I may be wrong on the year. Does anyone know how this "virtual" sensor works? The pcm dealer I'm working with wants me to get everything working using an actual sensor and then we are going to try the virtual setup for fun. His thoughts are if he can get the virtual sensor to work for customers he could literally make a plug n play setup for 99-02 harness.
12-21-2016, 02:15 PM
#53
On The Tree
Join Date: Jul 2007
Location: Largo, Fl
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
If you have I think 3.0 or newer version of HP tuners, its a simple drop down tab. There is a tutorial on HPTuners forum on how to do it. It took me 5 mins to complete it. My fuel gauge read backwards at first. I swapped in the values from a post on HP tuners forum and it started indicating correctly. I also had to install a pull up resistor on the tach signal. Bigmandengo told me to use a 10k resistor, and it worked perfect. So now all of my 1998 gauges are working on a P59 PCM using the avalanche OS and express van fuel segment swap. My flex fuel sensor is also indicating ethanol percentage through the VCM scanner. Its really sweet setup. I think Bigmandengo should package these setups and sell them as a bundle. He has been instrumental with helping my garbage get back on the road.
12-21-2016, 02:57 PM
#54
11 Second Club
iTrader: (8)
Join Date: Jan 2010
Location: Southern Idaho
Posts: 502
Likes: 0
Received 0 Likes
on
0 Posts
Here is some info I came across on the EFILive forum a while back regarding your question.
Posted by BLK02WS6:
Here is a writeup I found on the Virtual Flex Fuel Sensor - this was for the 2006 Impala, but the theory would be the same for any flex fuel vehicle that doesn't have a sensor...
"In the past, GM had some small trucks and SUVs that could operate on different mixtures of ethanol-based fuels. These vehicles used a fuel sensor in the fuel line that signalled the computer how much ethanol was present in the fuel; the computer would add or subtract the amount of additional fuel required. Now, the Impala flex fuel system can perform this analysis without using any additional sensors. GM has developed a Virtual Flex Fuel Sensor (V-FFS) software program that calculates the ethanol content in the fuel, instead of using a sensor to measure it. When the fuel level in the tank increases as the vehicle is refueled, the computer recalculates the percentage of ethanol in the fuel and automatically changes the air/fuel ratio. To do this, the computer temporarily stops the operation of other emission systems and monitors the oxygen sensors to determine ethanol content. The test is done several times until calculations remain stable. This can take several minutes when the engine is idling, but much less time at higher fuel flow rates."
and another I found:
"For 2006 and 2007 models, E85 compatible vehicles marketed in North America no longer use an alcohol sensor to determine and adjust for the alcohol content of the fuel in the tank. Instead, the vehicle "learns" (calculates) the alcohol content of the fuel, (and subsequent mixture in the fuel tank), through a series of measured adjustments.
Adjustments
After the re-fueling event, the system registers the amount of fuel that was taken on-board, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines the ethanol content of the fuel that was added. Based on that determination, it adjusts itself to the expected alcohol mix in the fuel tank and lets the fuel trim and O2 sensor activity fine tune the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or vice versa, can result in driveability symptoms due to the inability of the system to adjust for fuel composition (by not attaining the parameters necessary to reach closed loop operation). "
Link to actual post, post #14: https://forum.efilive.com/showthread...-ethanol/page2
12-21-2016, 03:48 PM
#56
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,446
Received 1,837 Likes
on
1,145 Posts
Threads like this are making it dangerously close to Ls1TECH again 
The following users liked this post:
fastsspr (10-05-2020)
12-21-2016, 05:43 PM
#57
On The Tree
Join Date: Jul 2007
Location: Largo, Fl
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
12-21-2016, 05:46 PM
#58
On The Tree
Join Date: Jul 2007
Location: Largo, Fl
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
12-21-2016, 07:28 PM
#60
On The Tree
Join Date: Jul 2007
Location: Largo, Fl
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
Yeah, it took me minutes. I will say, I still have a LOT of tuning to do. But, the car is getting better each day. Rolling around on a 3 bar, and flex fuel was well worth the headache of a repin, and bugging the **** out of Bigmandengo (sorry bro). Subeone can offer some knowledge as well as others.