birch64

what tables need to be modified when upgrading from a 2.73 to a 3.15 keep getting the p1870 code?

gojo

I would imagine HP Tuner does gear scaling in a similar way as LS1 Edit. There should be a table called Gear Scaling. You put in your tire size and new gear. If it's like Edit the shift points will also change, but you will likely customize them to your liking after driving a while.
someone with the HP should be confirming this.

birch64

were trying to program a 2000 coupe for the new 3.15 gear.we tried the gear scaling update, with no luck, speedo was off(about 8-10 mph) and wasn't shifting right,(p1870 code) i upgraded from 2.73 to 3.15 gear, stock GY runflats 275 40 18, (tire height 26.66 ?) 180 degree thermostat, anyone have there number's from a 2000 with a A4, what they should read for the hp tuner? or what are we doing wrong?


[Modified by birch64, 5:22 PM 5/30/2004]


[Modified by birch64, 5:22 PM 5/30/2004]

DragMan

Hell mine will not shift on WOT!

Droberts

Wayne, are you saying this is an HPTuner problem with programming your PCM for the 3:73 gears?

Thanks again for the HPTuner stock file.

Dennis

0rion

Ummmm, I'm an F-body guy so my knowledge of C-5's is limited but as far as I know you don't have to adjust the speedo for a gear swap on the C-5's. The sensor is after the carrier on C5's so the only thing that will throw off the speedo is a tire size change. With edit you make changes under the speedo tab to address the TCC slip that you're having(p1870). Someone with those gears and tire size will have to speak up though. I am pretty sure though that stock height is 26.7 if that helps any.


[Modified by 0rion, 3:57 AM 6/3/2004]

ToplessTexan

Orion is correct, the F-body and Y-body gear stuff is different. However you should not have to do anything with tire sizing to address P1870s. If you dink with tire sizing you will screw up the speedo. (If you see speedo error w/o touching the tire size stuff there's a problem.) Don't mess with tire sizes if you haven't changed your tires.

You can in fact verify that gear scaling has been correctly implemented by collecting OBD-II data including RPM, gear, input shaft speed, output shaft speed, and vehicle speed and doing a little math. Engine speed and vehicle speed are derived nearly directly from sensors (and can be very easily verified if you're being thorough.) The input and output shaft speeds are computed values and are directly related to the various gear and tire scaling factors. If these aren't as expected, the gear scaling ain't right.

Note that P1870 is triggered by differences between engine speed and input shaft speed and a scaling error that results in incorrect input shaft speeds can generate huge differences. LS1-Edit offered a workaround (still available) while they chased down the scaling... It was to make the P1870 test limits accessible so they could be relaxed. I needed at least 7-800 RPM limits to avoid component slip codes when swapping from 3.15 to 3.73 till it was fixed.

ToplessTexan

You've got a request for some more info from the HPTuners folks on the other board.