Hacking the Autobox ECU

[foxdie]

Hi folks,

Well, you all know me by now, I believe in sharing knowledge. This thread is a dump of my progress for hacking the Pre-facelift automatic ECU.

Phase 1 - Download the ROM from the Auto ECU
Phase 2 - Build a definition file
Phase 3 - Make a change and test it

Phase 1 was completed a couple of weeks ago, with a crocodile clip and some bare wire I was able to successfully download the ROM from the Auto ECU using an Openport 2.0 cable.

Phase 2 is now in progress, I've spent about an hour looking at this so far and this is what I've learnt;

Here's what we know so far;

* Although probably common knowledge - the pre-facelift autobox ECU's also have a 7201 chip inside - like the PFL engine ECU
* The 7201 ECU seems to favour some little endian tables whereas all the others seem to use only big endian tables (this threw me at first)
* The 7202 and 7203 ROMs are seemingly identical

Well tonight I crossed a milestone; I've successfully located the throttle position and first -> second gear shift point tables in the 7201 gearbox ECU

Here's a comparison between the PFL and FL tables (PFL is at the front, FL is behind it to the right).

pfl-fl-shiftpoints-1-2.png

We can see that between PFL and FL, Mitsubishi changed the shift points, the PFL holding gears longer and the FL shifting up sooner.

More to come, watch this space

[foxdie]

Second update!

Definition is done as far as I can get it using @BCX templates as hints to find locations. They can be found in the Definitive ECU ROM repository along with the others.

Couple of things to note;

* There were some oddities in BCX tables (I'm sure he did the best he could, it's a huge headache looking through hex) and those have transferred across, there are a couple of tables that don't seem right
* The MUT periphery table looks vastly different, presumably because it's a different ROM entirely

Another thing too, after bouncing some ideas against Confused and Nick Mann, I'm wondering if the unknown shift point tables are interpolated for the INVECS driver style learning. Here's a screenshot;

unknown-shift-points.png

The above is 2 pairs of tables, the ones on the left are the 1st -> 2nd gearshift tables, the ones on the right are 2nd -> 3rd.

It's widely known the main engine ECU has 2 fuelling tables; high octane and low octane. It interpolates between these depending on how much knock affects the octane rating (0-100). My theory is that, depending on how aggressive you are driving, it interpolates between the "known" and "unknown" table to choose it's shift point, with a variable (lets say 0-100 again) relating to driving aggressiveness.

I am thinking the "known" table is for hard driving, the "unknown" table is for gentle driving;

The harder you drive, the closer to the "known" table the gearbox shifts, holding gears longer.
The softer you drive, the closer to the "unknown" table the gearbox shifts, shifting up sooner.

I'm not sure. It's late, I'm off to bed. For now, at least we have something to play with

[Davezj]

sound like you have been hacking the **** out of this.

looks great.

[orionn2o]

Excellent work Jason

[foxdie]

Thanks chaps
@Confused has been helping out a lot and will help test some of the tables.

I've also approached someone to see if they can help us change the code to add torque converter lockup in 3rd gear too.

[Confused]

Yep I'll be testing some stuff out over the next few days, watch this space

[orionn2o]

Ideally you want to be able to set a nice drag racing style torque converter setting

[foxdie]

Question, has anyone mixed a early facelift autobox ECU (with the additional speed wire) with a late facelift auto gearbox (without the additional speed wire), or vice versa?

If so, were there any issues?

( @Davezj @adaxo @Wodjno you guys may know this? )

[Davezj]

I am not sure.
I think most of the swap that have worked are old PFL boxes with PFL ECU and these seem to be able to be fitted to any car.
I do have never old FL auto box and ECU in the back of my shed (buried under a load of stuff) and that configuration did not work for Nev in his PFL not sure if the box and ECU is early or late.
Nev or nick Mann would have more info on this.
@elnevio @Nick Mann

Sent from my MI 5s using Tapatalk

[Confused]

@Davezj if you get a chance to dig out the box and ECU, we'd be very interested to know the part numbers and processor type

[Davezj]

Easier said than done.
I can't get into my shed without taking stuff out of the door and it is right at the back with 10-12 feet of stuff in-between.
I think all the numbers from the box and ECU are already recorded on the forum somewhere, as Nev tried to get the box and ECU to work in his car but gave up and removed it. He fitted a PFL ECU and box I believe.
Which seems to be the only off the shelf combination that is proven to work in a PFL car.
Although my silver vr4 originally had a second gen box ( no external filter and OWC) with a plastic case ecu.
That is a 1998 car.
I have probably recorded those numbers on here as well.
I did a lot of searching for the correct pairings of box and ECU.
There are tables of the results somewhere.
@elnevio will know what the thread was called or some specific key words to search for it.

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[foxdie]

Posting an update.

Earlier today we successfully reflashed a pre-facelift gearbox ECU and improved shift time by 20%.

Video demonstration;



Keep in mind this car has a boost leak. There's potential for more

[rajvr497]

Great work @Jason...
more to come????

[Confused]

Yes, we certainly hope so!! This has definitely whet our appetites!

[Anderz]

Excellent, good work! A bit off topic but have you found how to control the TC lockup, or is it found for the FL Auto?

[Confused]

Not yet, but that is one thing that we are all interested in!

[Louis]

Well done!

[orionn2o]

Not yet, but that is one thing that we are all interested in!

if he works that bit out, i might just buy another vr4 just to play! I'm sure i'll have broken it in weeks...

[Confused]

Have modified a couple of entries in the VR4_AT_Base_PFL.xml file to correct ECUID and Case Part Number lookup... and maybe the MUT table too (although the MUT table looks better than it did, it may still not be correct!)

Capture.PNG

[foxdie]

Hi folks, here's a small update;

The gearbox mods have been trialled by fire at Santa Pod at the weekend and have also clocked up around 300 miles so far.

The best bit is the times. In 26'C ambient temps I clocked a 13.8 second pass, whereas a similar specced auto VR-4 without the gearbox mods clocked a 14.2 second pass (so nearly half a second quicker!).

We're still under the belief there's a lot more progress to be made but we'll keep updating this as more emerges