6.2L ECU tuning

TheCaddyMan04 · April 11, 2022

So, i'm running a hypothetical scenario through my head, and the basis on which i proceed with this, is based entirely on a few questions.

before i ask the question, let me explain what's going on, you're all going to tell me i'm insane, and that's perfectly fine. I have a 2004 Escalade ESV that i love dearly, and can't get rid of. i've been thinking about interior swapping the bits from a wrecked 2018 escalade esv that I have. i'd like to swap the cue system and the dash and door panels, and that's going to be a project in itself, trimming out pieces of the headliner and fitting them into the old one and recovering it, and likely same thing with door panels to resize them. i'm not worried about that. what worries me is how will i get everything to power on without the k2xx BCM? short answer is, i won't. and if i swap the BCM, it won't be happy unless it has its keyless entry module (meaning cadillac smart key, sweet), the ecu, tcu, and a number of other modules that are crucial to drivetrain and theftlock functions. i've already researched all of that, and thanks to GM Fleet tools, i'm more than confident in my ability to get everything but one piece working fine.

the ECU, of course i could run two ecus and just have the signals from the engine be tapped out from the original ecu to the secondary ecu for the gauges and start signal, but then i have to worry about where to mount both ecus and how to wire it without it being a total mess. and i would ideally like to be able to use the 10speed rather than the 4l65e that's in my truck right now. not to mention, i think with the column shifter from the K2xx, I'd have to. The 6.2L I have is unusable as the block is cracked from the collision, the front of the frame of the donor truck is totally mangled, it had a very rough front end collision, looks almost like it went full send into a tree. the ecu is still intact and responds just fine to GDS, it's very confused and upset, but still functional. I understand that the L92, or whatever that motor is designated, has all sorts of toys like cylinder deactivation, Variable Valve timing, gdi, cam and crank position sensors, plus the wiring for the vvt and DOD solenoids and actuators and what not. Would it be possible to tune the ecu so much that it will run a 6.0L LQ9? i know they're within the same family of engines, but a lot can change over the course of 14 years. we're talking about going from the most technologically advanced cam in block V8, to one of the simplest modern V8s. I'm sure it would be upset since it wouldn't see responses from most of its trick functions. a lot of open circuit codes for certain. i'm not 100% yet, but knowing GM, i seriously doubt they'd change the bellhousing for the transmission dramatically. would make my interior swap a whole lot simpler if i could run the LQ9 with just modification to the engine harness and ECU tune.

life is rarely ever this simple, i'm aware that i'm on my way into fabrication hell. this is the least of my problems, but i'd like to know if the harness i have to build will have to use both ecus, or if i can use just the one.

GM does this thing with the high speed canbus that makes it so that the ecu and tcu are essential, because they terminate the can lines. maybe there's an aftermarket ecu that can simulate all those can lines? or maybe i have to get creative with an arduino and a megasquirt? possibilities for certain.

CamGTP · April 11, 2022

Sadly you can not make the PCM/TCM and transmission function in this.

The engine and transmission must work together because of how integrated they are. They operate on a torque based model for the calibration unlike the computer in your current 2004 truck. Your Escalade is 2-3 generations of development behind the 2018 model year truck.

The engine calibration directly talks with the TCM to tell it what to do. The E92 computer can not operate an older engine like the LQ9. They aren't in the same family either. The LQ9 is an LS engine and the L86 is a LT engine with all that DI/AFM/VVT etc etc stuff on it.

I have not seen a standalone controller for the 10 speed yet but also have researched it lately.

TheCaddyMan04 · April 11, 2022

Dang what a shame, that's gonna hurt progress here. There's absolutely no way to make that ECU work? Only to use another Gen4 or L92? Also thanks for the correction, for a long time I thought the LT and LS were closer related than they were. If I'm being honest, I'm not a fan of the L92 because I've seen collapsed cam lifters so many times. And I guess if I were using an older engine like an LQ9 I'd probably have it refreshed so that it could be nice and clean, and maybe prepared for a magnuson super charger, maybe. So if I were to refresh an LQ9, it's certainly a possibility to refresh an L92 with better quality lifters. Just trying to make do with what I've got so far.

As someone that works on the electronics from this vehicle and similar ones on a regular basis, I see the parts, I can see the diagrams and power the modules up and play with things a little bit, but there's no engine there, I have an ECU and BCM and Keyless entry module and immobilizer all wired together on a table, and I can talk to them using my MDI, and I can see why they're all upset and not happy, I mean obviously, you'd be upset if you lost communication to your neighbors and thought that all of your doors were open too. I'm not too familiar with LS swaps or LT swaps, or even with HPTuners, but I've heard there's a lot that can be done with it. I kinda need that ECU for the power-moding, in order to use the smart keys for remote start, and to use the start-stop button, and to get the BCM to wake up to send the wake up signal for the gauge cluster, radio, onstar module, DVD Players, and HVAC system. The BCM would try to talk to the ECU and TCU, find it isn't there and then just stop right there, since it's waiting for signal from the ECU. also, I've noticed that the BCM won't respond or talk to the MDI without the ECU being present. I'll have to find a way around that for certain.

Also I wasn't intending on finding a standalone 10 speed TCU, was looking for maybe a standalone LS ECU that could talk to the Escalade's bus systems. Like maybe a plug and play standalone designed for the K2xx. This is a popular product for 80s BMWs and 90s JDM cars, I didn't know if the same thing crossed over to the world of GM.

TheCaddyMan04 · April 12, 2022

also, my apologies, its not a Gen4 L92, it is a Gen5 L86 EcoTec3. I'm sure the two are different, but as far as I know (not much) there's not much difference

CamGTP · April 12, 2022

There are the same in the sense that they are both 6.2 Liters. The L92 is a LS and the L86 is an LT engine.

Different blocks, cylinder heads, intakes, injectors and everything else. The LT engine controller can only operate the direct injection system, it can not operate a port fuel injection system. The high pressure fuel pump driven by the camshaft and all the sensors that go along with it play a role in everything for engine fueling.

I've been using HP Tuners for 10-11 years now, something like this just isn't possible to make work using these tools and the limitations we have with the factory controllers.

TheCaddyMan04 · April 12, 2022

So what you mean to tell me is that the DI injectors work differently than port fuel injectors? the solenoids operate differently? I'm guessing the system is looking for the pressure with the sensor, otherwise ecu would cut fuel supply to the engine? could there be any way to trick the ecu to think the sensor is working as intended? a resistor perhaps?

I'm fishing for an answer that I want because I can't accept the answer that is. I guess I'll just have to get another L86 to make this thing work. that or maybe just use the original ECU and have the L86 ECU sitting so that I can use the car. I could send the sensor signals to both ECUs so that I get display on the cluster, I'm pretty certain tach is measured in different ways, so I would probably have to use an arduino with a can shield in order to translate the LQ9 tach signal to the signal for the L86 ECU. i imagine the transmission computer would be happy to see tach signal. I could wire the LQ9 ECU's CEL line to the cluster, at least they didn't change that, then it's just a matter of "fixing" as many sensors and actuators as I can to solve the barrage of DTCs that the L86 ECU will have so I can have remote start be happy and so that I can pass inspection. for inspection i could use two OBDII ports, one for the ECU that runs the LQ9, and another that would go through the serial data gateway module for the L86 systems.

maybe I'm thinking too deeply into this, I'm trying to gain full factory like functionality. maybe I should just simplify things and find another L86 somewhere.