P219B after AFM delete on stock cam, already had a Trifecta AFM-disable tune. Need a retune or is it something else?

TQUAP · June 9

Hi all,

I've got a 2018 Escalade ESV (6.2L L86 w/ 10l80) that I recently had an AFM delete done on (Texas Speed kit with the base/stock cam, so no change in cam profile). I'm about a 6/10 driveway mechanic but this was a bit too detailed a surgery for my taste, so I farmed it out to my regular mechanic. Joe was rushing to get it done before vacation and is now gone for two weeks. After I picked it up, the CEL came on after a couple of miles and it's throwing a P219B (air/fuel ratio imbalance, bank 2). Both long term fuel trims are steeply negative, with bank 2 running about 5 to 7% lower than bank 1.

One thing worth mentioning on the tune side: I loaded a Trifecta tune about 20k miles ago, right after I bought the truck, specifically to disable AFM in software. That same tune is still on the truck. Joe did not touch the tune during the delete, so it's running the original AFM-disable Trifecta file on top of the fresh delete hardware.

I'm driving it sparingly until Joe gets back but would like an idea of what I'm working with before then. He's convinced we're looking at a bad fuel injector that just happened to go south right after the delete (color me slightly skeptical, but he's a good guy and I'm sure he'll take care of me either way).

When I logged the parameters and looked at the data, one thing that came up was whether the truck was properly re-tuned after the physical delete. My assumption going in was that with the base cam, the only tuning needed for an AFM delete is just turning AFM off, which I'd already done in software. But I'm now wondering if the truck actually needs a proper re-tune for the delete hardware and that's what's driving the P219B.

So my main questions for the group:

Do I need a dedicated re-tune after a physical AFM delete even if I kept the stock cam, given the truck is still running the same software AFM-disable tune from 20k miles ago?
Does a bilateral steeply negative LTFT with a 5 to 7% bank split point more toward a tune issue or toward Joe's bad-injector theory?

And of course, any other thoughts on what could be going on here are very welcome.

TIA

newdude · June 9

10 minutes ago, TQUAP said:

Hi all,

I've got a 2018 Escalade ESV (6.2L L86 w/ 10l80) that I recently had an AFM delete done on (Texas Speed kit with the base/stock cam, so no change in cam profile). I'm about a 6/10 driveway mechanic but this was a bit too detailed a surgery for my taste, so I farmed it out to my regular mechanic. Joe was rushing to get it done before vacation and is now gone for two weeks. After I picked it up, the CEL came on after a couple of miles and it's throwing a P219B (air/fuel ratio imbalance, bank 2). Both long term fuel trims are steeply negative, with bank 2 running about 5 to 7% lower than bank 1.

One thing worth mentioning on the tune side: I loaded a Trifecta tune about 20k miles ago, right after I bought the truck, specifically to disable AFM in software. That same tune is still on the truck. Joe did not touch the tune during the delete, so it's running the original AFM-disable Trifecta file on top of the fresh delete hardware.

I'm driving it sparingly until Joe gets back but would like an idea of what I'm working with before then. He's convinced we're looking at a bad fuel injector that just happened to go south right after the delete (color me slightly skeptical, but he's a good guy and I'm sure he'll take care of me either way).

When I logged the parameters and looked at the data, one thing that came up was whether the truck was properly re-tuned after the physical delete. My assumption going in was that with the base cam, the only tuning needed for an AFM delete is just turning AFM off, which I'd already done in software. But I'm now wondering if the truck actually needs a proper re-tune for the delete hardware and that's what's driving the P219B.

So my main questions for the group:

Do I need a dedicated re-tune after a physical AFM delete even if I kept the stock cam, given the truck is still running the same software AFM-disable tune from 20k miles ago?

Does a bilateral steeply negative LTFT with a 5 to 7% bank split point more toward a tune issue or toward Joe's bad-injector theory?

And of course, any other thoughts on what could be going on here are very welcome.

TIA

Lets throw the tune out the window for a second.

Was everything installed correctly during the delete? All of the injectors are plugged in? Intake gaskets were replaced with new ones? You did replace the stock cam with a DOD delete cam, correct?

Oxygen sensors. Do you have OEM sensors on the truck at all 4 locations? Are any of them aftermarket?

Texas Speed sells a DOD tuner as an option with their kit, but all it does is turn off AFM. Its states that its for use with the stock profile non DOD cams, and any other cams require proper tuning and not just DOD disabling.

So to me, that throws that part out the window, and you've got a sensor, electrical or mechanical cause for the P219B.

TQUAP · June 9

Unfortunately the most I can speak to how everything was reassembled is that I have used Joe quite a bit and he's always proven knowledgable, capable and honest. As to individual things he did I just can't say. I do know that he was under a time crunch to get all of this done and personally if I were in that situation I know I would be more susceptible to making minor mistakes. Though he did tell me he took the truck on an extended test drive after buttoning everything up and it did not throw a code for him.

With everything I know about the situation and as a layman, if I had to hazard a guess I'd say there's a non-trivial chance something minor that was overlooked. I was kind of hoping to narrow it down to a smaller subset of possibilities so I could have a more useful conversation with him.

A DOD-delete cam did come with the kit and the pictures Joe provided of the job indicate it was installed.

To my knowledge all O2 sensors are OEM. I purchased the truck at 75k miles about a year ago and the sensors were never replaced under my ownership.

On the intake gaskets, I supplied the parts and I did specifically purchase and give Joe all new gaskets to install. Anything that was indicated to be one time use, I purchased a new one of and supplied to him.