Blackbear Performance Review

[Geotrash]

If you have a bidirectional scanner and use the mfr's codes by VIN (not generic OBD) is there a fuel composition or alcohol content value, or a reset function?

I do (hp tuners and a tech 2) and I’ll plug them in and find out. Not sure if a tech 2 will work with this rig.

 

[Fless]

So it’s been interesting. I’ve been doing a good bit of “general” maintenance (will post in the 3500 thread I have) but VIN lookup at the parts store has the question about flex fuel or non-flex fuel engine. I believe my truck to be non-flex as it was a fleet vehicle and came with a sticker “GASOLINE ONLY”.

I do not have a factory sticker indicating anything else.

That's pretty conclusive that it's not a FF system.

 

[Geotrash]

If you have a bidirectional scanner and use the mfr's codes by VIN (not generic OBD) is there a fuel composition or alcohol content value, or a reset function?

So here's what I found with HP Tuners, using their scanner app. Alcohol content was not a default channel for the app's home screen, but I was able to add it and then scan the ECU to see if there was any data available there. Sure enough, there is. Now I don't know if it's a calculated value based on O2 sensor data, or an actual hardware sensor value, but at least the ECU is capturing alcohol content data as a percentage. And the value seems plausible. Note, the ignition was on but the engine wasn't running for the screenshot below.

 

[Fless]

So here's what I found with HP Tuners, using their scanner app. Alcohol content was not a default channel for the app's home screen, but I was able to add it and then scan the ECU to see if there was any data available there. Sure enough, there is. Now I don't know if it's a calculated value based on O2 sensor data, or an actual hardware sensor value, but at least the ECU is capturing alcohol content data as a percentage. And the value seems plausible. Note, the ignition was on but the engine wasn't running for the screenshot below.

View attachment 444783

I can't imagine that there is a physical sensor on it, so I would bet it's a calculated percentage. They dropped the physical sensor from the GMT800s around 2005 or so.

 

[Geotrash]

I can't imagine that there is a physical sensor on it, so I would bet it's a calculated percentage. They dropped the physical sensor from the GMT800s around 2005 or so.

Thanks, Steve. I think you’re right about not having a physical sensor, but I guess the question is still open as to whether or not it’s actually a stealth flex fuel truck.

 

[Fless]

Curiously, gmauthority says it's FF:

https://gmauthority.com/blog/gm/gm-engines/l96/

I would be inclined to do a little test with some E85 -- know your fuel trims with E10 first, then maybe mix 1/3 E85 (probably E50 or E70 at the pump) with 2/3 gas and see 1) if the STFTs go way positive, or settle down to a good value and 2) see what HP Tuners reads for alcohol content. And not a full fillup, just less than 1/2 a tank if it becomes an issue.

EDIT: I take that back, didn't read the fine print. Article says FF in the Savanna and Express only.