kr when downshifting...

[ssminneapolis]

ok..i have gottan my ltfts to where i want them to be...done some timing work and gottan my 02's where they need to be.

but i seem to be having a kr problem when downshifting...the KR starts in cell [4000rpm/.76] and goes from there as you can see...

it was suggested to me that i manually downshift before mashing it, and that worked...i have been told some TCC changes maybe be the trick to get this working...but i am not sure where to go with this...any help would be appreciated...

[jimmyblue]

Look at what your O2s are doing, in the cell or three before
the KR blip appears. Most likely you will see them hit the floor.
If so, find the MAP and RPM that you are hitting at that same
event, and bump up the VE table at those coords by a couple
of points, and hand-smooth-in the surrounding area.

I believe the mechanism here is that the MAF, MAP are both
changing, the PCM steps back into SD mode, and the SD tune
is a bit too lean for reality. Attacking the KR blips this way has
worked out pretty well for me.

[ssminneapolis]

out of the 5 episodes i have recorded in the last log...only 1 of them had an instance where the O2's dipped...and only slightly, 5-7...and it recovered right after.

[jimmyblue]

Dipped 5-7 ??? You mean like from 870mV to 863mV, or
what?

Recovery will happen as soon as the MAP re-stabilizes.
But by this time you will have been hit with KR.

Stock KR "jumps up" too much for my liking and goes away
too slowly, like a mooching brother-in-law. You could reduce
the aggravation level by reducing the attack rate and upping
the recovery rate (I use 0.100 attack and 0.200 recovery).
This reduces the ability to protect against real ping but is
a lot more tolerable.

But you might try the VE bumping anyway, until you see the
O2 voltages -rise- on shift / tip-in events you haven't gone
"over the top" yet.

[ssminneapolis]

yeah...sorry, from 5-7mV swing...the 02's are pretty steady at 880 at WOT. i am going to give the TCC apply/release a shot. see if that helps a little....if not..then i guess i will just have to remember to manually downshift everytime i mash it on the highway.

thanks for the help...

[02denali]

so was this ever resolved. i am having the same problem now after the 80e swap.

[ssminneapolis]

i have solved it for the most part....i modified the TCC settings inthe tranny. after that i didn not see any KR...i haven't logged anything lately as i just haven't had much time and the weather has been pretty crappy...

shoot me a PM if you want the exacts...

[mustbbrent]

Silly rabbit tricks are for kids. Well of course we want the exacts. (please and thank you, sir )

It's the only place i have left that has KR... Does driving 55-65 and mashing the go pedal give you a steady 4*KR but in contrast, if you mash the go pedal from the light you have all goodness and no KR even through that same RPM and MPH range sound familiar? And BTW, thank you immensely for your previous help.

One other question, other than at idle, I haven't found any place where I can push too much timing. I mean, I have the full 60* of timing all across the top and an average of 5* more timing in part throttle areas than you, though 2* less at WOT cells. I wonder if it is related to that high stall converter I still have installed. I took your advice but have not found a place nor time to have it fixed. Comments?

[ssminneapolis]

below are the settings in the TCC apply release...i tried just about everything to get rid of this stuff...this is the only thing that actually worked...actually devised it from a bit of advice from another gentlemen...

from work i have done on a few other trucks..the actual settings are going to depend on how sloppy (or whatever is causing this) your truck is...
256 256 256 256 256 256 256 256 256 256 256 256 256 256 256 256 256
43 43 43 43 43 50 57 66 75 75 75 75 75 75 75 256 256
36 36 36 38 44 48 56 76 97 136 255 255 255 255 255 255 255
256 256 256 256 256 256 256 256 256 256 256 256 256 256 256 256 256
45 45 45 45 45 45 45 45 45 45 45 45 45 47 50 65 68
38 38 41 43 44 46 50 56 62 77 82 143 186 255 255 255 255

with regards to your timing inquery brent...when i had my cable my truck was getting a new tranny...(snaped the output shaft on the old one...lowing kit related - bad angle...thank you warrant) and now that i have my truck i do not have my cable...should have it back here this week so i have some serious work to do...

but as far as my timing table...it was based off of someone elses...i modified it a little to smooth it out a bit but since then i haven't had time to do anything with it...

[mustbbrent]

The bin file I sent you is really old... as in 20 or so revs old, now. if you want a new one. i incorporated the good stuff i saw in yours to what was good in mine. My tranny stuff will seem wierd though as I have the 3200 stall to deal with and I lock it up when under part throttle. Good to catch up with you... I went to the silveradoss.com forum for the first time since September last year or so. WOW. what a difference. . Let me know if you are interested when you get your cable.

[BQuicksilver]

You could reduce
the aggravation level by reducing the attack rate and upping
the recovery rate (I use 0.100 attack and 0.200 recovery).
This reduces the ability to protect against real ping but is
a lot more tolerable.

Into which tables exactly did you insert these values, or did you multiply certain values by these factors?

[mustbbrent]

Go look at Engine - Spark Retard - Spark Retard... then Base Recovery Vs. RPM and Recovery Rate vs. RPM... Hope this helps.

Into which tables exactly did you insert these values, or did you multiply certain values by these factors?

[BQuicksilver]

Go look at Engine - Spark Retard - Spark Retard... then Base Recovery Vs. RPM and Recovery Rate vs. RPM... Hope this helps.

Don't those tables both control recovery? Which controls attack?