regorih

2002 Tahoe L59 flex fuel
P01 Controller
OS: 12216125

2004 Tahoe L59 flex fuel
P59 Controller
OS: 12587603

2004 C5
P59 Controller
OS: 12587603

Has anyone gone through the trouble of making their C5 flex fuel ( the ability to run pump gas or E85 on the same tune)?

So far the only scenario I imagine could work world be to use an 2004 C5 PCM ( in my case my C5 is a 1999-would require repining the connectors) and do a fueling segment swap to enable the flex fuel capabilities and install the flex fuel sensor.

So am I full of it or is this something that is possible?

Thanks,
Roger

all4spl

Oh I like this thread. In for more info.

jimbos'ss

Vengeance racing has done it, but they aren't saying much about the custom coding that was done for it to work.

lsxvette

Subscribed

regorih

Can someone donate a 2004 PCM and I'll explore what is needed to be done?

Rkreigh

the Haltech Elite does this nicely love to hear more about doing it with the stock c5 pooter or some other lower cost alternative

regorih

I think it would be more cost effective to find the tahoe ECU and do all the corvette segments swaps into it because you could pick one up (tahoe ECU) for about $50-$100 vs a c5 ECU that I was quoted at $300 used. I find it funny how the basically same ECU is worthless from a tahoe but a gold nugget from a C5.

youngrigo

In for more info as i'd also like to go this route

BLOWNBLUEZ06@RKT Performance

Don't forget you have to get the PCM to sync up with your BCM.

regorih

Thanks for the heads up.

This link covers this step.

https://www.corvetteforum.com/forums...m-tcs-etc.html

all4spl

I'm hoping you get this project running properly. I'm dying to get flex fuel.

regorih

I actually have no intention of doing this conversion to my car. I don’t have the time to try it out. The only reason I thought about was because I did an engine and trans segment swap on a 2000 Silverado that switch to a 6.0 and 4L80e. Realizing the door of opportunity that segments swaps allows has opened up a world of new possibilities to me.

I hope this information makes someone that has time to go out and prove a theory of mine.

ajrothm

Definitely sub'd.

What about the Trailblazer PCM swap?

regorih

I have no idea


The only reason I used the Tahoe L59 example is because it's the only flex fuel calibration I could find that has matching OS numbers with a 2004 C5 EC.

regorih

My theory based on a non 2004 C5:

1. Buy a 2004 ECU that has the following:
Service Number:12586242
Hardware Number: 12583660
Which in turn should have the OS: 12587603

2. Have a VIN number swap done. (I’m not even sure who, what, when, or why this is done) I’ve never been in a position that called for this process to take place.
3. Go to hp tuners bin repository and get a 2004 Tahoe L59 file and do a Fuel System segment swap. Make sure it has an OS: 12587603
4. Go to hp tuners bin repository and get a 2004 Corvette file and do an Engine, Engine Diagnostic, Transmission, Transmission Diagnostic, System, and Speedometer segment swap. Make sure it has an OS: 12587603
5. Re-pin the connectors on the ECU harness ( In my case 1999-2004)
6. Do a ECU to BCM sync covered in post #10
7. Wire in the Flex fuel sensor to ECU (Note: I’m not even sure if the flex fuel sensor are compatible to each other)
8. Plumb Flex fuel sensor to fuel delivery line
9. Tune the vehicle and make more power!!

Like I said before I have no idea if this would work, so I’m just throwing it out there. Feel free to tell me where this recipe would FAIL!!!

Thank you for your time and I’ll keep on hunting more ways to make MORE POWER!!!!

Smoove

I wouldn't mind running flex fuel. Just in case I go on a trip and can't find E85 though really. I run 87, 93, or E85 in my tahoe with a custom tune and I love the fact that I can run all 3 fuels, not do anything, and notice an actual difference in at least two of them(87 vs E85). It feels like you go from a stock vehicle....then to a vehicle with a tune in it. Seeing that Vengeance does this but doesn't sell a kit to me sounds like some retrofitting is needed, in house.

regorih

I wish I had a flex fuel vehicle to scan and see how it reacts based on the fuel it has running. Did you tune the Tahoe yourself? If you did how does flex fuel work from a tuner perspective? From example what table are used in hp tuners for low octane like 87 and which once does it switch to when the flex fuel sensor reads higher octane levels AKA E85?

Rkreigh

I'd worry about integration with the vehicle with an ecm swap

I think a megasquirt pro 3 could do this job too by splicing in

need a pretty nice fuel system upgrade depending on HP goals

Smoove

I unfortunately did not tune it myself. Benefits of being in the bizz in Florida so long is never a shortage of tuner buddies. However, I'll have HP tuners for the vette soon, will also buy enough credits for tahoe. By the time I have it....you'll have worked it out probably lol.

Anti_Venom99

I have been researching this myself. It seems you would need an 04 c5 pcm with an OS from some van/Tahoe BUT it's only 2 bar capable.

I'm not very computer savy but how hard would it be to build a custom OS based on the Tahoe OS but just change the flex fuel portion to a newer flex fuel vehicle?