Flex fuel addition

[Carbibbles]

Ive been searching around but I cant seem to find any definitive information on this subject. Can HPTuners add/enable flex fuel support to a previously non-flex fuel vehicle? I am looking for a solution that would involve installing an ethanol content sensor into the fuel system and wiring it to the stock PCM, upgrading injectors and fuel pump, and enabling flex fuel in the stock OS or possibly writing another OS to my PCM that will support flex fuel. This is purely for a performance application of e85, I am not worried about the small loss in fuel economy.

My particular vehicle is an 03 sierra, but I would also like to be able to do this for other cars in the future.




Thanks

[mbray01]

If I recall correctly, no, would require the e85 pcm, and harness, or minimum connectors, to rewire. Also would need higher flowing pump, lines, rail, and injector. Now if you had a wrecked vehicle to harvest it all from, the by all means yes. I believe the main part is the pcm, though, not just the os.

[tweaker47]

It is possible. We have an '03 1MB ECM (P59) running OS:12579405 from an Escalade. I've seen it done on 12587603 as well. Just wire the signal of the flex fuel senor to pin 56 on the blue connector. The other two wires are 12v power and ground. (A->Pin 56 Blue, B->+12vdc, C->gnd).

You change:
ENGINE > FUEL > OPEN & CLOSED LOOP > FLEX FUEL > FLEX FUEL ENABLE
ENGINE > FUEL > OPEN & CLOSED LOOP > FLEX FUEL > DEFAULT 38% (FROM A FF TAHOE BIN)
ENGINE > FUEL > GENERAL > AIR FUEL RATIO > STOICH AFR (COPY THIS TABLE FROM A FF BIN)

Enable DTC's p0178 and p0179 and set them to 1-mil on second error

I may be forgetting something but I think that it is. The flex fuel tables are newer. They showed up when i went from 2.24.660 to 2.24.666.

[LSxpwrdZ]

It's available on nearly all OS's on the P59 controllers now.

[mbray01]

I didn't realize the p59 was in the 03 trucks. my mistake

[Carbibbles]

Ok my truck has OS 12579405 and a P59 already. So I should be able to just wire the sensor in, enable it, and set up the tables right?


Thanks for the help

[truckdoug]

I'm gonna be giving this a shot on my 5.3 swapped truck this summer.
Interestingly enough, the ford fuel composition sensor seems like the ticket. rescale the for the ford sensor's range (50-125hz vs. 50-150hz for the chevy one)
http://ls1tech.com/forums/pcm-diagno...6#post18179068
that link has another link in the thread for gen 4 guys.

it's a popular sensor in the import world
http://www.supraforums.com/forum/arc...t-647997.html?

the benefit is it has threaded fittings unlike the GM sensor, but is pinned out just like the GM one. and it's cheaper too.

[abrowne70]

i currently have a LS1 over here in australia and my os was 12225074 then i converted it to 1bar SD. Can anyone help me with how i can get the flex fuel tables into my tune because i have just updated to the latest version of hptuners and the tables aren't there.

[SSUte01]

12225074 is from a P01 (512Kb) PCM from memory not a P59 (1Mb) PCM. If some of the US Gen3 trucks ran flex fuel with the P01 you could use that OS and go from there. That's where I'd look short of custom OS or finding it buried somewhere in the code providing it exists for 12225074.

[maxgee]

Sorry to bring this back from the dead. I have an 02 C5Z and using a P59 PCM from an 03 Tahoe. I am having codes come up on for heated o2 sensors 0135 and 0155.
I believe the P01 uses a different way to ground the sensors versus the P59.
Anyone have this scenario and know of a solution?

[socal99]

yes I remember reading the truck have a different pin out for the O2's when doing this kind of swap on a c5 vet to get flex.

https://www.corvetteforum.com/forums...same-tune.html

[Falcadoor]

How did you go with the flex fuel Im wanting to do the same thing and finding nothing but problems

[TedKt]

Did anyone get the flex fuel to work with the P59 PCM in an F-body? Having the same issue; O2 heater DTCs and not reading alcohol content. 2004 GTO file. OS: 12587604.