Curious if my ECM in my 05 Silverado is flex fuel compatible. I plan to install the sensor and run the wires to the ECM and enable it in hptuners, but I can't find definitive info on whether this ECM will support it.

 

I made mine flex fuel compatible. I added the sensor, gave it a 5v reference, and it works perfectly. I went to the track and ran my best time on pump gas. I swapped to E85 and ran my best time without changing the tune. Whatever ethanol percent my truck has in it, it runs great.

I do use EFI live, but you should be able to do almost everything I have done with HP Tuners.

 

L59? If that's the RPO code it should already be Flex fuel enabled.

The 1 MB PCM uses a virtual flex fuel based on 02 sensor feedback. There is no Flex fuel sensor like on the 02 512 MB PCM.

I understand you can not just enable flex fuel as it will not work correctly. Some of the necessary Tables are not Shown in the Tuning suite software. You need to do an entire write with a flex fuel OS from the same year model.

 

Do you have an ethanol gauge or do you monitor ethanol content somehow? I have the gauge installed and ready, I just wasn't 100% sure the P59 ECM was flex fuel compatible. Because yours is an 05, sounds like it is. You would have the same ECM as me.

L59 I believe is an engine code. P59 is the ECM code and certain ECM's are flex fuel compatible, others simply aren't. They can't recognize the signal from the flex fuel sensor.

I'm not looking to just enable flex fuel in HPT, I was inquiring about whether the P59 ECM will recognize the sensor. I will install the sensor, wire it to the ECM, and my tuner will tune the truck for flex fuel. I'll run E85 primarily, but if I'm on a roadtrip and need to use 91, I'll have that option.

 

L59 is the flex fuel RPO.

Never heard of it as referred to as a P59 computer always LS1A and LS1B

LS1A is the early style PCM's in Corvette and Camaros like 97-98
LS1B is everything above 99-07 classic at least in the trucks

I have not seen it done the way Gadgetized is describing it on an 05 1MB PCM. I know it has been done on the 512MB 411 PCM's

I know the 512MB system was already set up to use the sensor.

The 1 MB PCM used a virtual flex fuel table from the factory. Not sure how to wire in the sensor If you need a custom OS or not.

 

My truck was RPO LM7, standard fuel truck.

Yes the information is not conclusive. Wiring it in is the simple part, tuning it is the simple part, and even finding a flex fuel OS to use on my ECM would be simple, but I just don't know for sure if my ECM is even compatible.

When I burn my HPT files, it recognizes the ECM as "P59 Gen III V8, 4.3L V6"

 

Ok, I believe they classify their stuff differently.

I Use and am more familiar EFI Live my self.
I have purchased HP tuners but I just can't get used to it.

 

I wired in sensor #13577379. I can get you my service number from my PCM later today if you wish. It was pretty simple actually. There was a little tinkering with the tune, but nothing major. I have it inline for my fuel return to my tank.

 

Sweet just the info I needed! If you wired the sensor in and enabled it in HPT or EFI Live then that means your ECM is flex fuel capable. Do you remember if you changed your OS when you installed the sensor? Or just enabled it.

 

flex fuel shouldn't be pcm specific. Just flash in the flex OS and go.