My current fuel trims - idle, 2000rpm, 3000rpm all no load

[Mudsport96]

I will add a caveat. It could be looking for an ethanol content, but that would mean that a no -flex vehicle had a flex ecm installed. So since the I jectors for the flex engine are larger, it would have to trim positive to get the same mixture.
But lm7 injectors are 30% smaller so I would think the trims would be higher

 

[Fless]

He will be fine to mix a 1/4 tank of regular to 3/4 tank e85. Yes the trim will max out, but that is the point. To full duty cycle the injectors and run the most ethanol through them as possible because it is a very good cleaner. I ha e done it in my nonflex Silverado and yes it will guzzle the fuel, just light cruising will not blow it up.

E0 while great in a vehicle that can use it, will typically cost more per gallon. And not fix his issue.

A scanner will not help determine the ethanol content. It will only show lean or rich.

He doesn't seem to think E85 is available around him, so it may not be an option. But "caveat emptor." He's concerned about high LT fuel trims now; the suggestion was to reset the LTFTs, and run E0 and good fuel system cleaner to see if the LTFTs would come down with pure gas.

A scanner might show the alcohol content, and it would be interesting to see. What's to lose by looking? My Tech 2 showed it on my FF truck but, of course, it's probably looking specifically for the FF options of the VIN. Just curiosity on my part.

I don't have much to add to any of this discussion; until some controlled testing is done and results shared, we're just guessing at what could be off enough to make the LTFTs a little high. The other unknown item is that there might be an updated engine computer calibration that might affect any/all of this issue. Lots of "what-ifs" and variables to consider and work through. Or just worry about why it's not "right."

 

[2006Tahoe2WD]

He doesn't seem to think E85 is available around him, so it may not be an option. But "caveat emptor." He's concerned about high LT fuel trims now; the suggestion was to reset the LTFTs, and run E0 and good fuel system cleaner to see if the LTFTs would come down with pure gas.

A scanner might show the alcohol content, and it would be interesting to see. What's to lose by looking? My Tech 2 showed it on my FF truck but, of course, it's probably looking specifically for the FF options of the VIN. Just curiosity on my part.

I don't have much to add to any of this discussion; until some controlled testing is done and results shared, we're just guessing at what could be off enough to make the LTFTs a little high. The other unknown item is that there might be an updated engine computer calibration that might affect any/all of this issue. Lots of "what-ifs" and variables to consider and work through. Or just worry about why it's not "right."

Thanks to everyone putting brain power on this.
Yesterday went for a ~100 mile trip and the LTFTs came down a bit.
I searched for non-ethanol gas near me and it looks like the 76 station near me has it. I'm going to go check it out and fill up if they do. I certainly will report back.
In the mean time I continue to work with Foxwell to get my scanner working again.
As a reminder I have two "scanners" 1- Foxwell NT510 Elite (currently on the fritz) and a OBD Link MX+ (using this to graph FTs on my iphone while I drive).

 

[Mudsport96]

A scanner might show the alcohol content, and it would be interesting to see. What's to lose by looking? My Tech 2 showed it on my FF truck but, of course, it's probably looking specifically for the FF options of the VIN. Just curiosity on my part.

Your 2004 still has the mechanical ethanol sensor, so it will show alcohol content in the fuel. Late 05 and up do not have that sensor so they estimate.

I don't have much to add to any of this discussion; until some controlled testing is done and results shared, we're just guessing at what could be off enough to make the LTFTs a little high. The other unknown item is that there might be an updated engine computer calibration that might affect any/all of this issue. Lots of "what-ifs" and variables to consider and work through. Or just worry about why it's not "right."

Yeah he'll, if he is not the original owner, a previous owner may have even put junk aftermarket injectors in and that is causing g an issue

 

[2006Tahoe2WD]

Your 2004 still has the mechanical ethanol sensor, so it will show alcohol content in the fuel. Late 05 and up do not have that sensor so they estimate.

Yeah he'll, if he is not the original owner, a previous owner may have even put junk aftermarket injectors in and that is causing g an issue

I did take a look at having the injectors serviced/clean by WitchHunter.... I used them before but they are no longer doing business. I'm not the original owner but the original owner serviced at only the dealer per CarFax and that's why I bought it.

 

[Fless]

Your 2004 still has the mechanical ethanol sensor, so it will show alcohol content in the fuel. Late 05 and up do not have that sensor so they estimate.

Which is why I thought it would be interesting to see 1) if a scanner would show what it thinks the alcohol content is, and 2) how that tracks to what's being put in the tank.

 

[2006Tahoe2WD]

Which is why I thought it would be interesting to see 1) if a scanner would show what it thinks the alcohol content is, and 2) how that tracks to what's being put in the tank.

Yes, that would be interesting. If I get my Foxwell working and if it will read that value I will sure post all that here.

 

[2006Tahoe2WD]

Anyone have an idea on the PID "name" for alcohol percentage? This assumes my non-flex 2006 Tahoe has a PID for that. I might be able to read a custom PID if the OBD Link MX+ doesn't have it already named.

 

[Fless]

Are you using software that is available with the MX+? What's it called?

I'm using an MX+ with Torque Pro, but I don't think it has the alcohol content PID to show.

 

[2006Tahoe2WD]

Are you using software that is available with the MX+? What's it called?

I'm using an MX+ with Torque Pro, but I don't think it has the alcohol content PID to show.

It seems to just the software that comes "with" the dongle. I created an account and downloaded the software from iphone app store. I think the name is obdlink.
I might be able to use other apps - I don't know.