2005 Silverado Installing ethanol content sensor

[Andyb756]

Hey guys looking to install ethanol content sensor in 2005 silverado. Is this possible with out too much hassle. I’m running the custom os2 for valet mode and upgrading fuel system

[joecar]

Does your OEM/base OS support physical alcohol content sensor...?

[Andyb756]

It is not a flex fuel truck stock. I was just curious if i wired a sensor up and turned the tables on for the sensor in the tune if it would work and if not what I would need to do to make it work

[GMPX]

I think you would have to attempt to run a factory tune that already had the FlexFuel active, there is a lot of tables and parameters in the background that need to be set up and may have never been populated in some applications where FlexFuel was never going to be an option. It isn't as simple as flicking the FlexFuel enable switch and it all works.

[Andyb756]

I’ve got a flex fuel tune I’ve saved from a different vehicle on my laptop and it seems to have all the same tables as mine. I would copy those tables to mine. Just curious if this would work or if anyone has done it.

[GMPX]

No that isn't what I meant, the tables you see in EFILive are only a small part of the story. There is a lot of obscure tables and parameters in the background not shown in EFILive that are required to work as well.

[Andyb756]

Ah I see. Thank you

[Andyb756]

Did some digging and would it be possible to do a segment swap and cal flash it in? Having the capability to automatically switch back and forth between fuels would be nice

[GMPX]

Whilst that is possible it swaps everything in that segment which means every parameter/table (visible and not visible) from the E85 calibration goes in to your vehicle. That could cause problems with different vehicle configurations. An extreme example would be to swap a Corvette segment in to a truck would cause all sorts of issues.

[Andyb756]

I found a file with the same os number and same year just with flex fuel enabled. I might give it a shot and if it doesn’t work i can always go back. Thank you for answering my questions. I’m planning on adding boost and just looking for a little flexibility with fuel options.

[Supercharged111]

I found a file with the same os number and same year just with flex fuel enabled. I might give it a shot and if it doesn’t work i can always go back. Thank you for answering my questions. I’m planning on adding boost and just looking for a little flexibility with fuel options.

This requires a full flash, not a simple flick of the switch or mere segment swap. It has been done on LS1Tech though. I was initially thinking LS1b.

https://forum.efilive.com/showthread.php?27572-Flex-fuel-OS-for-LS1-PCM

But the GenIV stuff is similarly simple.

http://www.trucktrend.com/how-to/engine/1604-how-to-convert-a-gen-iv-gm-truck-flex-fuel-for-more-power/

[Andyb756]

Yeah gen lv stuff looks way simpler. From what I’m reading I have a p59 ecm with green connector which has dbw which I don’t plan to change from. There is kind of a rabbit hole of information to jump down with this topic all which has no real clear cut solution haha. I have built a file with engine and fuel system segments and also a complete file from a same year same os dbw flex fuel truck. I’ll play with this and see what works and report back

[1FastBrick]

The 05 uses a virtual flex table based of 02 sensor feedback, however if you wire up an ethanol content sensor, it will read from the sensor.

As mentioned, You need to do a full flash from a real flex fuel enabled operating system.

[Andyb756]

Ok I will definitely do that. I ordered a sensor and pigtail off eBay and will be doing flex capable pump and injectors as well. When it all shows up I plan to spend a Saturday installing and adjusting tune if need be

[Highlander]

What operating system are you trying to enable...

[Andyb756]

Ok everybody my sensor and pigtail made it all the way from China yesterday to my home. 43 dollars and 3 weeks later I’m flex fuel capable. I made a line to connect the sensor in between the rail and supply line. I segment swapped engine parameters with a same year flex capable avalanche and scripted my settings back in all tables except flex fuel tables and full flashed my pcm. Wired sensor in and read 6.6 percent. I’ve been running 87 e10 so possibly they were a bit low on the corn. I had half a tank and 4 gallons on non ethanol fuel so I dumped that in and test drove. During drive it dropped down to 4 percent and the sensor reads at 54 hz and zeros out in scanner if I unplug. Seems all is working well and I want to grab some e85 and see if alcohol content reads accordingly. Bigger injectors and fuel pump to follow before I’ll fill up with e85. One question if anyone can answer is what do you set b3103 flex fuel default percentage at? I set it at 10 since that’s what the pump said it could be at.

[Andyb756]

Put 5 gallons of e85 in and ran it with success. Pump said anywhere from 50 to 83 percent ethanol. After 2 minutes or so of driving ethanol content rose to 21 percent and stayed. I was shooting for somewhere in that range don’t want to run it lean and I haven’t gotten injectors yet. Throttle response is smooth and no knock retard at all.