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does box code matter?

compudude86

CEG'er
Joined
Apr 28, 2011
Messages
414
Location
Algonquin, IL
I have an ATAQ0 ECU, with a KCA3 box code. Say I went to the junkyard, and snagged an ECU off a similar year mystique, with a different code on it, (basically, connectors are the same) and put my KCA3 tune on it. would it work? Is the code specific down to the hardware level, or is it the tune file itself that makes the difference?
 
I'm pretty sure the tune would be specific to the PCM code. Like with the SVT SFG0, SFG1 and SFG2 are different revisions of the same code. Now they can be used in the like year and optioned car, however a tune would be the same when compared to the other code.
 
Short answer: the tune file makes the difference, but the hardware may also complicate that.

Long answer:
When I tuned my SE, the last time, I first upgraded from CGB1 to CGB3 by flashing. Then I proceeded to tune. The differences between CGB1-CGB3 were minimal, I recall mainly the RPM adder for when the AC was turned on went up some. But the code was fairly different. A binary diff. of the two showed two completely different binaries, sharing only a small percentage of code.

Not much changed in the hardware of the boxes, and it is fairly likely that the software from one box may run on similar hardware from a different box, but tuning it is a different story. Most tuning happens by modifying a parameter at well known location. That parameter is very likely to be in a different location for the different box codes, and your tune specifies this parameter(s) and their location explicitly.

I would assume that if you had a KCA3 box, and replaced it with a KCAx box, you would have to have your tune redone for the KCAx binary.

Some other things to think about would be the VIN# change. Some software/handhelds may not let you use your tune on another ECU, even if it IS the same box code. This is normally due to licensing, not because it wouldn't work.

Out of curiosity, why would you be getting a junkyard PCM?
What are you using to tune? Xcal2/3?
Are you tuning it yourself, or was it done by a shop/mailorder?
 
I am using a Delta Force Tuning Sniper tuner. For the cost and the tuning options, it fit at the time. At the time, I also didn't personally know someone who could get me a deeply discounted price on an SCT pro racer setup like I do now, so that might be a future move. I am looking at replacing the ECU because I am convinced it is failing... after replacing my engine, and loading my tune, everything worked fine. I decided to do a minor adjustment to my tune, it said "all done", I unplugged it, switched the key on, everything behaved normally. I did a keep-alive reset, by disconnecting the battery and turning on the headlights and turning the ignition to drain all the power out, and when I reconnected the battery and started the car, I had the PATS flashing 16, about communication with the ECU. It starts and runs, but to this day, still flashes after starting. I ran FORscan and ran a PATS test, and after running the test, the light goes out, and it tells me no problems found, but upon key cycle the light is back. I also have had other erratic intermittent issues, where at times the RPMs go up and down and act like something is getting funky readings, it isn't the harness as I inspected the whole thing and rewrapped it before installing, and all my sensors come back fine on inspection. I also had an issue where my power steering leaked, and ATF ran down inside the ECU. I opened it, cleaned it with alcohol, and used compressed air to get rid of any remainders, but I figure the damage could already be done. I am also lucky in that this is a E0 98, so PATS is a separate module that isn't affected by an ECU swap.
 
Do you need the tune to run the engine? For example, do you have larger injectors, FI, or non-stock MAF that needs the tune to run the engine right?

If your tune is only a performance enhancement, try reverting to stock, and see if you have the same issues. It seems suspicious to have the issues after meddling with the tune.

Try to remove as many troubleshooting variables as possible. Since you have replaced the engine, and the tune, there are several possible points of failure.

Can you datalog? Maybe that could provide some useful info about the engine's behavior.

I'd think it would be far more likely to have a vacuum leak and a pinched wire, or a bad tune file, than it would for the ECU to go bad.

As for the PATS... have you ruled out the possibility of the issue being with the PATS module rather than the ECU? I'm not very familiar with the separate PATS modules... I wonder if defeating/bypassing/removing the PATS system (if reasonably possible) could help with diagnosing the issue more thoroughly.

I'd definitely try to make sure that the ECU has the same symptoms on the stock tune (if possible) before replacing it. It could also be a bad write of the tune file or various other issues related to the tune.
 
q: been using sct and i was considering the pro racer package but i am open to other options; the sniper tuning looks expensive, what do you have from them? air fuel monitor? data logging software? this just allows you to datalog not write tunes right? thats crazy expensive.
 
... this just allows you to datalog not write tunes right? thats crazy expensive.

It is a full tuning suite. Not just datalog.

If you have an Xcal2/3 you have one of the best datalogging capabilities for our cars. IMHO, Might as well stick with it, and pick up the PR package. But I'll let the OP speak about the Delta Force stuff...

BTW, Why not create your own thread asking about it? It'd get a lot more visibility...
 
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