my friends 98 ta is shifting way before its calibrated wot shift points

[Eric]

Hi, recalibrated my friends 98 ta for him and everything is good except for the wot shift points , i left them as is at 6000 for the 1>2 and 5900 for the 2>3 , 5900 for 3>4 but when logging i noticed the the 1>2 shift was very close to 5500 and the 2>3 was very close to 5700, everything seems good as i corrected for a gear change in speedo calculator to input the correct pulses per km and output shaft revolutions and i did a shift point correction also because of the new 3.42 gear , could it have to do with the wot shift speeds even thought they were corrected when i did a shift point correction, i am sure gm wanted these shift points so they set the wot shift points to 6000 and 5900 and then set the wot shift speeds so it would shift at 5500 and 5700 and when i corrected for the 3.42 gears that all stayed the same , so i am thinking i should up my wot shift speeds , the wot shift speeds are way below what they would be at the wot rpm shift points but i noticed that the difference is less for the 2>3 and maybe this is why it is shifting closer to its wot shift rpm, so am i on the right track or is it something else , i will have the car this afternoon , if what i am saying is correct it will be trial and error to fix this to the desired shift points i want by uping the shift speeds at wot , thank you Eric

[Chuck L.]

Maybe, get some help here??
http://forum.efilive.com/showthread.php?1723-How-about-a-transmission-tuning-tutorial!&highlight=4L60e+shift+speeds

[joecar]

The WOT shifts require both WOT RPM and WOT MPH to be met...

so, to shift at a specific WOT ROM, set the WOT MPH a little lower, and then by trial/error adjust the WOT RPM until the actual shift RPM is achieved.

[Eric]

Thanks Chuck , nice thread lots of information , nice work Joe, so i was on the right track about the wot shift speeds , Joe when you say set the MPH a little lower do you mean the MPH at my wot shift rpm , so i caculate what my MPH would be at lets say 6000 which is my desired wot shift rpm and i set it back a bit , really that is trial an error , well looks like i wont be doing this tonight , does this also go for my 2000 silverado truck or is it specific to 97,98 pcms, thanks Joe

[joecar]

Set one of them down a little (so it is met first), and use the other to set the actual shift point (so it is set second).

[Eric]

Ok i will try that Joe , oh have another question concerning the same log , i also logged the pid feul system a and b and i noticed it is always in closed loop , can this be under wot , it has to go into pe at wot , am i just not getting the info because of a pid mix match , i believe i did not build the log file while connected to his ta , i just used the log file that i use on my truck , is this where my problem is , but i think i remember that when i connected to his ta before logging it did validate the pids, in the log i can see the commander afr which looks normal at about 12.5 at wot and my o2s did not go below .903v at wot and that is close to 13.2 afr , i dont want to connect my wide bands , i just want to make sure it is getting into open loop , thanks Joe what would we do without you, Eric

[joecar]

Not just me, but all the contributors on this forum, they have given their time and experience... :)


Look at his tune file, what does B3616 say, this is the condition for going into PE (it should also go OL).

[Eric]

Yes i know i am a bit confused about the open and closed loop , i know it should be in open loop until warmed up and closed loop relies on nb sensors for feul ajustment , my truck goes into open loop because it is supercharged , i have done no ajustments that concern feuling as you can see , feuling is all new to me but it will not be for long , so it is normal that my friends 98 ta stays in closed loop because it is set up that way in the tune and my truck because of my supercharger will go into open loop at wot and will not rely on the nb sensors for fueling but rather PE , does all this make sence or am i way off track , i imagine when supercharged the mixture is way to rich at wot to have any accuracy using nb o2s, i have seen as low as 11.7 on my trucks widebands but commanded was a bit lower so when i do become more in tune about all this i will fix that, thanks Joe hope you can clear all this up a bit for me , Eric

[Eric]

Thanks Joe , you got back to me as i was sending you my last reply , so what makes sence about all i said , i will check out B3616 and get right back , Eric

[joecar]

If the AFR is more than a few points off from stoichiometric, then the NBO2's can't trim so it goes OL.

[Eric]

Just checked out B3616 and the table goes from 64% at low rpm and 29% at 6000 of tps to enable PE , so it should go into open loop , so closed loop is only near stoichiometric , makes sence , so why in my log am i not seeing it go into open loop , feul system a and b is a valid pid for the 97, 98 pcms, could i have set up my log configuration wrong , meaning while not connected to the car , thank you Joe, Eric

[joecar]

Post log file and tune file.

[Eric]

Hi Joe , sorry about the delay in getting back here is the tune and log file , dont worry about the title , it says stock because i just saved them as from stock and did not rename it like i should have , 1116911170 thank you

[joecar]

PE:
Log shows PE kicking in. Use a wideband to verify.

WOT 1->2:
shifted at ~5500; add 200 rpm to the WOT RPM and see if it shifts at 5700; if it does, keep adding 100 rpm until it shifts at 5900-6000.

WOT 2->3:
shifted at ~5850; add 100 rpm increments until it shifts at 5900-6000.

[Eric]

Thanks Joe , yes that is what i saw , it is going to PE because the commanded AFR drops to 12.15 and the short term feul trims go to 0 , your right i should connect the widebands to be sure , so why is my feul system pid A and B not indicating open loop in the log , i here you on the rpm shift points , i could also leave my wot shift point rpm at 6000 and up my wot shift point speed until it shifts at 6000 , would that work , thank you Joe

[joecar]

I've noted with some OS's that the pid FUELSYS A/B keeps saying CL even tho commanded AFR/EQIVRATIO indicate PE fueling...

I don't know why it does this.

[joecar]

BTW: using the scantool->tuneool cursor linking feature, I saw that your logged commanded 12.15 AFR comes from the PE table.

[joecar]

T...
i could also leave my wot shift point rpm at 6000 and up my wot shift point speed until it shifts at 6000 , would that work , thank you Joe
If you set the shift rpm to 6000, then the shift might overshoot that (i.e. it might shift at 6200 which is where the rev limiter is).

i.e. if the PCM sees both points triggering at the same time it shifts past those points.

The key is this: set both rpm and mph lower, and then increment the one you're interested in until the shift happens at the right point.

Examples:

say you want to shift at 6000 rpm (which may correspond to say 38 mph):
then set the shift to 5700 and 34, and increment the rpm until the shift happens at 6000.

say you want to shift at 38 mph (which may correspond to say 6000 rpm):
then set the shift to 5700 and 34, and increment the mph until the shift happens at 38 mph.

[Eric]

Ok Joe i will try it that way, so it can be normal that my friends car will not show it is in open loop when selecting feul system pid because of the operating system , but like you said it was commanding 12.15 so this says that it was in open loop, thanks Joe
If you set the shift rpm to 6000, then the shift might overshoot that (i.e. it might shift at 6200 which is where the rev limiter is).

i.e. if the PCM sees both points triggering at the same time it shifts past those points.

The key is this: set both rpm and mph lower, and then increment the one you're interested in until the shift happens at the right point.

Examples:

say you want to shift at 6000 rpm (which may correspond to say 38 mph):
then set the shift to 5700 and 34, and increment the rpm until the shift happens at 6000.

say you want to shift at 38 mph (which may correspond to say 6000 rpm):
then set the shift to 5700 and 34, and increment the mph until the shift happens at 38 mph.

[joecar]

Yes, some OS's show CL all the time while others show OL-Drive during PE.

[Eric]

Just letting you know that everything is good on my friends ta , i checked the afr with my widebands and like you said it says CL in the log but it does go into open loop , car goes great with the new gears and the work i did on the tranny , what a difference, thanks Joe Eric
Yes, some OS's show CL all the time while others show OL-Drive during PE.