PCM Diagnostics & Tuning HP Tuners | Holley | Diablo
Sponsored by:
Sponsored by:

Why does changing trans pressure affect idle

Thread Tools
 
Search this Thread
 
Old 08-03-2015, 05:01 PM
  #1  
10 Second Club
Thread Starter
 
dw456post's Avatar
 
Join Date: Nov 2005
Posts: 891
Received 67 Likes on 51 Posts

Default Why does changing trans pressure affect idle

In HP Tuners, when I change the trans pressure from 92.8 to 90.1, my idle tune goes to crap. Barely starts and will not idle--then dies---multiple tries.
The same thing happens when I modify other shift pressure tables.
Any explanation?
Thanks
Old 08-13-2015, 02:50 PM
  #2  
12 Second Club
iTrader: (3)
 
Brando5641's Avatar
 
Join Date: Apr 2010
Location: NW Arkansas
Posts: 248
Received 1 Like on 1 Post

Default

Shouldnt. Did you unknowingly make the modifications to a old tune and flash it in? I have done that a time or 2. I like to pull the tune off the car if it has been a while since i have messed with it just in case i didnt save it the last time.
Old 08-13-2015, 03:10 PM
  #3  
11 Second Club
iTrader: (18)
 
thunderstruck507's Avatar
 
Join Date: Mar 2008
Location: Northwest AR
Posts: 8,358
Received 26 Likes on 18 Posts

Default

Are you doing a couple key start cycles with some idle time to let the PCM adjust after flashing the tune?

Seems common the first couple starts after a tune flash the car will behave a little off. If everything isn't 100% spot on it might just be a matter of the PCM relearning some fuel trimming and idle.

EDIT: I did just see that you have a 2005 GTO. The only one I messed with in EFI Live has separate controllers for engine and transmission so I wouldn't think my above post would apply in this case since you would be flashing the transmission controller not the engine controller.
Old 08-13-2015, 04:36 PM
  #4  
10 Second Club
Thread Starter
 
dw456post's Avatar
 
Join Date: Nov 2005
Posts: 891
Received 67 Likes on 51 Posts

Default

Originally Posted by Brando5641
Shouldnt. Did you unknowingly make the modifications to a old tune and flash it in? I have done that a time or 2. I like to pull the tune off the car if it has been a while since i have messed with it just in case i didnt save it the last time.
I made the change to the current tune, saved it as a different tune, and did a write calibration only. Weird.
I loaded it twice to make sure nothing happened loading it. Started the car multiple times and had to change it back. I was trying to soften the 1-2 shift on my street tune. I finally modified my shift time to .900 and it still shifts firm, but better. Trans has fluid mods and a shift kit so it is kinda hard to soften it up.
Thanks for the replies



Quick Reply: Why does changing trans pressure affect idle



All times are GMT -5. The time now is 08:45 PM.