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Discussion Starter · #21 ·
@figgie good stuff. I will check the TCCS reference material later.

Yes FCA/Stellantis has been at the front of the bus security push with the highest theft rates in the business. Teslas are enigmatic too. Auto execs are diving head first into locking down their vehicles and ensuring service only at their branded outlets. The point they are missing is, vehicles that are easy for owners to keep on the road stay on the road. If a security bit sets and locks out the vehicle start system, it now becomes a 2 ton lawn ornament and there is nothing an owner can do except tow it to a dealer. I have seen glitches in over the air updates do this already, because the vehicle has to be immobilized while modules are updating. A packet has to come in to re-enable the vehicle when updates are complete, and if that packet doesn't come in the vehicle thinks its still in the middle of a flash. You have to have deep security access to fix this.

Also stay on your toes about CAN protocol differences. You can't take just a powertrain from a CAN FD vehicle and swap it to a CAN 2.0 vehicle for example. Even if the body, engine and trans are the same, the modules and harnesses are not. Some vehicles now have over 40 modules on the network and the PCM gets vital messaging from most of them.
 

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Also stay on your toes about CAN protocol differences.
CAN is all over the place. It's like the schizo chassis wiring the Japanese did in the 90s with some of their cars with OBDII changes happening during or around same model generation facelifts. I've heard all of the Germans have been using their own variants of the Bosch system since the 90s, and then the other OEMs came on in the 2000s with their own versions, etc.
 

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Discussion Starter · #23 ·
And that's really the heart of the modern problem with vehicles. Every OEM group still depends on multiple suppliers to provide the modules and support for the network. Its possible now to have a particular module for the same model and model year made by more than one manufacturer. If you happen to need a module at some point there is no guarantee the one you find in a junk yard will work 100% with your configuration even if it plugs right in. The resulting random gremlins will then force you back to the dealer where they will use your VIN and BOM to find the correct module hardware version you need, then you have to find out if the software in that new module works with everything it talks to. You may need the dealer to reprogram stuff to complete the repair. Most repair labor now is just fooling with all of this stuff.
 

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Those pictures on post #1 are just trim resistors that are added at the factory after the initial wave-solder build was complete. There is nothing tuned there. To do that you need to get the code out of the chip ROM and onto external memory of some sort so that it can be tweaked. Since the assembly language was known only to Denso and their customers it took some very smart guys in Japan to reverse engineer how the CPU works since it is like nothing available commercially at the time. The hardware was very dedicated to making an ECU and looking back I can absolutely state that they were a generation ahead of the industry at that time thanks to the insane resources that the Japanese "Bubble" economy of the late 80's allowed. It must have sucked to work for Detroit or Germany and see the electronics sophistication coming out of Japan during that time and knowing it was totally inaccessible to you.

Of course OEM tunes are conservative. They have warranty and customer perception concerns that aftermarket industry need not worry about. When the stock ECU goes open loop under high power you can feel the loss of power immediately and it is plain as day in the datalogs. Start pulling fuel out of the open loop map and you can make a lot more power but you better know when to stop. The stock ECU also pulls timing for so many reasons including just generally driving aggressively and high temperatures. Lots of places in the code to "find" more power if you don't mind a blown engine here and there.
 

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all of the Germans have been using their own variants of the Bosch system since the 90s, and then the other OEMs came on in the 2000s with their own versions, etc.
On BMW specifically, I can tell you safely that they adhere to CANbus specs with no deviation usually using little Endian for things like dash messages and big/Intel endian for other more complex messages between subsystems such as between ECM and ST/TC systems.

The one thing they are doing is they are using seperate CANBus for;

Powertrain (ECM, stability control, traction control etc)
Comfort (AC, Interior Lighting, heated seats/steering etc)
Power (relays etc)
Safety (Air bags, ABS)
Gateway (facilitates comms between different CANBuses)
Security...what we are discussing here.

Then add in Linbus for wiper control (1 wire vs 8, another trick Bosch piece used on prancing ponies) and other security features and it becomes a spaghetti!
 

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Discussion Starter · #26 ·
@3p141592654
Thanks for the comments. I think the question of was anything done to tune this ECU is a closed case. Later I will update this thread after I compare OL fuel from these two ECUs cold starting from the same temperature. May take a while because I need to get a UEGO.
 

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So in my case, the "modified" ECU ran the car last year, but with some caveats...
After putting the intake and exhaust back to stock last year, adding back a catalyst and installing a new and properly located O2 sensor,

The engine also sometimes cranks a little long and can stumble to a start hot. As for power I would say its adequate but definitely not over what I would expect form a stock 7MGE. Unfortunately I have not gotten around to buying and installing a UEGO yet although my new down pipe has a boss for it. I will add that to the list of to do over the winter.
Did it do those "caveats" before you put the stock intake and exhaust back on, or after?

Agree that it's pointless to talk to JET, they're a bunch of scammers and idiots if they're even still around.
Well, I'm very pleased with their Stage 2 Quadrajet. :)
 

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The level of knowledge in this thread is absolutely fantastic - thank you @BonestockNA @figgie @3p141592654 for taking the time to share your collective knowledge here. Simply AWESOME stuff!


Did it do those "caveats" before you put the stock intake and exhaust back on, or after?



Well, I'm very pleased with their Stage 2 Quadrajet. :)
Thieves that do right by a few people are still thieves. 💩

Granted, so much time has passed since they offered their 'service' to 'tune' those ECU's that it's likely a lot of their employees and maybe even their management and owners have no idea that happened. I'd still avoid them like the plague, regardless.
 

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Discussion Starter · #29 ·
Did it do those "caveats" before you put the stock intake and exhaust back on, or after?
This car came with headers and a wide open exhaust which I did not drive much before changing it back to stock. Did not get to drive it like that in the heat but I can say the crank times were always long with this car. First thing I noticed when I got it. Engine always idled correctly and everything seemed in order except for lazy starting and the soot. The old Bosch plugs I took out were sooty too. No codes ever set on this car either.

After putting the stock exhaust back on with an HKS cat back I was more satisfied with the drive, but it still cranked long sometimes and some warm/hot starts would crank for a few seconds then stumble on runup. WOT performance was not the best either and I can say that the modified exhaust setup made better power at WOT, while my current setup feels better midrange.

After replacing the ECU and testing last week, I could see an instant startability difference cold and after fully warming up. Good 7Ms always jumped to life by my experience and now mine does that repeatably. Bad weather and salt will keep me off the roads for a long while but I will add on to the thread when I know more. It is possible the ECU I got with the car had a problem the whole time, but the behavior I described was why I suspected a tuning resistor was changed.
 

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The level of knowledge in this thread is absolutely fantastic - thank you @BonestockNA @figgie @3p141592654 for taking the time to share your collective knowledge here. Simply AWESOME stuff!



Thieves that do right by a few people are still thieves. 💩

Granted, so much time has passed since they offered their 'service' to 'tune' those ECU's that it's likely a lot of their employees and maybe even their management and owners have no idea that happened. I'd still avoid them like the plague, regardless.
@chevydude
A quick look at JET's catalog of parts, it looks like their current hustle is sourcing cheap OE style replacement DBW throttle bodies for GM engines, putting a few scallop cuts in the throttle body inlet and slapping a JET sticker on it, and selling it for $250-400 as a 'plug and play no tuning required' 'upgraded' throttle body.

If it was any upgrade at all, it'd require tuning. Insane that they're still up to their bullshit after all these years.
 
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