VIII patch to reset fuel trims?

[sub7]

Did anyone tried disconnecting the ecu connector itself? Much easy that way. For JDM 8, try disconnect the middle one (where both +12v pin are wired)

[Fast_Freddie]

You are mising the point... I wanna reset it with a patch... and not disconnect anything...

[sub7]

That definitely the whole point reset the fuel trim and I just suggest something easier than disconnecting battery. Can't imagine I got to re-tune my favourite radio channel and clock each time battery reset.

[wreckleford]

If you plug out the ECU plug you wouldn't have to reset the radio and clock, but a patch is definitely preferable.

[logic]

I've actually considered just wiring in a normally-closed momentary switch to the power line for the ECU; there's been more than a few cases where I'd have liked to wipe RAM and start from a completely fresh boot, but digging the ECU harness out of the dash isn't typically very convenient.

Of course, neither is rooting around under the dash, installing yet another switch. I'm running out of room for attractive installs of switches and LEDs.

[acamus]

logic, tephra can you write a patch?

for 94170015:

create function which checks 0x10 at variable FFFF8DC8
if bit is set calls sub 14302 and at the end sets r0 to 1

replace function reference from sub 20D02 to the offset of new one at 8B98

then clearing CEL would clear trims even in case there is no CEL.

[acamus]

Nobody wants to write a patch , I had to do it manually in hex as I do not have build environment set yet .....

Here it comes fully untested with no warranty for 94170015.

00008B98                 .data.l sub 39000

00008BF8                 .data.l sub 39000

sub 39000:                              
00039000                 mov.l   r14, @-r15
00039002                 mov     r15, r14 ; 
00039004                 mov.l   @(h'14,pc), r10 ; FFFF8DC8
00039006                 mov.w   @r10, r10
00039008                 extu.w  r10, r0
0003900A                 tst     #h'10, r0 ; 
0003900C                 bf      loc_39014 
0003900E                 mov.l   @(h'10,pc), r0 ;  sub 14302
00039010                 jsr     @r0 ; sub 14302
00039012                 nop
00039014                 mov     #1, r0
00039016                 mov.l   @r15+, r14
00039018                 rts
0003901A                 nop
0003901C                .data.l FFFF8DC8    
00039020                .data.l sub 14302

HEX

00008BF0  00 02 0F D4 02 08 FF FF  00 03 90 00 02 10 FF FF

00008B90  00 02 0C D0 01 80 FF FF  00 03 90 00 02 01 FF FF 
 
00039000  2F E6 6E F3 DA 05 6A A1  60 AD C8 10 8B 02 D0 04  
00039010  40 0B 00 09 E0 01 6E F6  00 0B 00 09 FF FF 8D C8  
00039020  00 01 43 02 FF FF FF FF  FF FF FF FF FF FF FF FF

[logic]

Sorry for not getting a chance to look at this, acamus, but your patch looks basically right to me. Also, 96530006 is basically the same thing, but you'd need to change sub_14302 to sub_14172.

I'll try to test this today when I step out for lunch, it certainly looks straightforward enough.

[SEEnoEVO]

Let me know if this works for the 96530006!! This would be very nice!!!

[acamus]

My only concern is whether the flag at FFFF8DC8 stays set long enough to reach engine on/off checks @8B98 and @8BF8
otherwise more changes are needed.

[JohnBradley]

The easiest way to reset trims is to not use them. Trims are so 1999 :P

[logic]

Aaron, just let me know when you port jcsbanks' SD patches to 96530006, and I'll be happy to give up my fuel trims. (Which reminds me, I really need to get jcs' DMA logging patches added to 96530706 at some point, I really miss the logging rates I had with that.)

acamus, looks like I'm not going to be able to test this this afternoon; earliest I'll be able to look at it is tonight. So, someone else might want to take a quick crack at it if they're in a big hurry to know if this is workable.

(I still think hooking this into tephra's map switching is probably a good idea as well, though; switching between E85 and E10 usually results in at least a little bit of a swing in trims for me, despite having things dialed in pretty well.)

[Fast_Freddie]

I can't do it today either... I am still on the 0011 rom anyway as i do not use map switching... I have a patched 0006 rom already, just haven't had a chance to didldle with it...

[Fast_Freddie]

Bump since I don't have the listed ROM for the test patch...

[acamus]

Now that we know that some actuator commands are not used in some ROM's, we have the opportunity to write patch that uses spare "dedicated" command for doing this. Fast_Freddie are you still interested? What is your ROM ID?