4L60E WOT shift 1>2

[maudyZ28]

Hi Guys,

tuning a friends car and the car have NEVER shifted at WOT 1>2 at the commanded point,
limiter is at 6600 rpm
shift at 6500 rpm
WOT vss threshold 52 kmh-1 (about 4500 rpm as indicated by efilive)
part shift is ~4 kmh-1 below WOT vss
part downshift is ~ 3 kmh-1 under upshift at all TPs
dont recall WOT downshift
wot threshold is 95 % TP

the car appears to consistently shift at 6000 rpm. even though every other gear is setup the same and shifts right on 6500?

also we did increse rev limiter to 6700 rpm and if seem to shift at 6150 rpm, but on the next run the car just hit the limiter ?

What could be going on. Do I need to decrease part throttle Vss shifts ? and WOT downshift?

[joecar]

Hi Maudy,

Try setting both the WOT MPH and WOT RPM values lower and see if it shifts...?

Does he have a cam...? Is he getting DTC P0121 (look at C3905)...? Do you have a log...?

What car/engine/pcm does he have...?

[maudyZ28]

hi Joecar, thanks for the reply. I have come to rely on you for your knowledge and would like to thank you for always getting back to me (and the other guys on the forum)

Ok,
LS1 camaro, lS1B pcm with COS3, stock bottom end, full top end upgrades, 228/232 cam @ 0.050" lift with 0.58X/0.58X lift, 241 slp ported heads, full exhaust + intake etc. Full TCi streetfighter gearbox and 3600 stall, strange 12 bolt.

Will check the P0121 code, don't think it is there. I did do a search and read up about this but will double and triple check. He has a log that I sould be able to post if he sends it.
Strange thing was the run where we adjusted things it ran well (best NA time he has had with the setup). Then I changed the timing on launch as they car knocks here (think it is mechanical as it doesn't go ewven when pulling loads of timing out) and then it didn't shift.

I will try setting the part shift vss (up/downshifts) lower and the WOT vss and rpm shifts much lower (5500 rpm ish) and let him run the car and see if it shifts. Then sneek them up again.

[joecar]

Go back to the tune file that shifted ok... and discard all the tune files after that one (i.e. the ones that the shift fails)...

then make your changes again (and save as with new filename) and see if the same thing happens

[ the idea here is to see if maybe the tune file was corrupted or something ]

[joecar]

More info (yes, I know, it's from HPT): The curse of the P0121 Code...

[maudyZ28]

thanks Joecar.

Ok I see, maybe that's a possibility. We can test this.