Downshifting from 3rd to 1st?

[Cool28]

When I'm cruising in d at 40 and floor it it goes to 2nd for a sec then goes to 1st. Is there a way to have it go right to first? It would have a great kick for 40 mph rolls if I could get it to do this.

Thanks

[joecar]

Post your tune file.

[Cool28]

http://forum.efilive.com/attachment.php?attachmentid=12781&d=1331606957

[Cool28]

Don't know this one might not be the right one. I don't have my car laptop handy right now

[joecar]

Is your differential ratio (3.00) correct in the tune file...?

[joecar]

Try setting D0960,1,2 to 100% all cells.

[Cool28]

Yes rear gear is 3.00. First gear is good to 57 or so mph.

Ok I'll change that thanks

[Cool28]

well guess that was a old on checked my latest file and thats already at 100%

heres current file13416

[Cool28]

oklooks like the downshift is 35 instead of 40 but ya still doesnt go from 3rd to 1st at that speed.

[joecar]

I'm thinking it over...

are VSS and TPS both correct...?

[Cool28]

2to1 is 35 mph at 100%tps. 3-2 is 61 at 100%. Kickdowns are also all at 100%. My laptop died so that's all I got.

[Cool28]

Hmm I wonder if it's see a 3-2 just before it see 3-1. Have to check 3-2 tps below 100%.

[joecar]

The 3->2 and 2->1 tables each have to trip...

but they should trip in rapid succession (would appear almost simulataneously, no momentary pause at 2nd)...

[joecar]

Try this: raise the last few cells of D0906 to say 45 mph.


( also, D1206/7 seem a little low to me, I usually see these at 94/84, but I don't think this is causing it ).

[Cool28]

ok made those adjustments. Ill find out when i get my car back from paint this week:)

[Cool28]

Loaded it up still can feel it go to 2nd then 1st.

[joecar]

Can you make this happen at part throttle...?

[Cool28]

I don't think so I can try it

[Cool28]

I don't think I can cause it will only drop to 1st from 3rd at 80% throttle or so

[Cool28]

Ya know at part throttle it did go from 3-1 lastnight. But then went right back into 2nd since it point is so close. Freaking thing leaped when it did do 3-1:). Now wonder why it won't do it at wot?

[Cool28]

Still having this problem when floored from 3rd it goes 2 then 1. Anything I can do? I've done what was said above still no go.

[joecar]

Hmmm, this is a hard problem...

log GM.SHIFTLAST and GM.SHIFTDELAY.

[Cool28]

Ok will do as soon as I get my car back from getting rims on:)

[Cool28]

Need to charge my laptop then ill log it

[Cool28]

heres the log.

[Boost]

Post a video when you get this to work right ! :banana:

[joecar]

I ran out of time today... I'll look at the log tomorrow.

[joecar]

The log shows three 4->1 downshifts as follows:
- frame 298: delays 0.75s before shifting 4->3 in 0.093s; then delays 0.0s before shifting 3->1 in 0.140s;
- frame 514: delays 0.35s before shifting 4->2 in 0.110s; then delays 0.0s before shifting 2->1 in 0.078s;
- frame 858: delays 0.03s before shifting 4->3 in 0.109s; then delays 0.0s before shifting 3->1 in 0.095s;

the shift delay is the delay between the PCM deciding to shift and the PCM commanding the shift (this implies the PCM was not ready to command the shift yet for some reason);

the first case would be noticeable (0.75s delay), the second case would maybe not be noticeable (0.35s), the third case would not be noticeable (0.03s)... is this what you perceived when taking that log...?

[Cool28]

Ya so was in 4-1. So it goes to 3rd then 1st. That would be the reason for the delay then. Anyway to fix 4-1 delay?