PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

PCM "Unlearned"???

Thread Tools
 
Search this Thread
 
Old Jan 31, 2003 | 06:36 AM
  #1  
Mr. B's Avatar
Thread Starter
11 Second Club
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Feb 2002
Posts: 3,934
Likes: 0
From: NY
Default PCM "Unlearned"???

A 1999 Formula with bolt-on's and cam (no heads) has LS1-Edit done by a well-know shop in June of 2002.

The car was re-dyno'ed because a loss of power, and while on wide-band reveals a 12.1 A/F ratio.

No changes were done to the car.

Is it possible for the PCM to "Unlearn" or overwrite the tune originally done?

If it is possible, how would/could it be prevented?

<small>[ January 31, 2003, 10:39 AM: Message edited by: mrb00formula ]</small>
Reply
Old Jan 31, 2003 | 05:32 PM
  #2  
gwj's Avatar
gwj
TECH Addict
 
Joined: Nov 2001
Posts: 2,003
Likes: 0
From: Live Oak, FL - in the woods where the creatures lurk.
Default Re: PCM "Unlearned"???

"Is it possible for the PCM to "Unlearn" or overwrite the tune originally done?"

The PCM will not "overwrite" any changes made to the "permanent" registers, nor will loss of power to the PCM. It's possible the STFTs/LTFTs will adjust, as these are operational adjustments that the PCM will make.
When you get/make a custom tune, you are placing values in the computers' memory that stay there until removed by the same methods.
There are still adjustments that the PCM makes
constantly while you are driving,using a different type of memory.
Hope this is clear enough?
Reply
Old Feb 2, 2003 | 12:34 AM
  #3  
Tim Sloper's Avatar
On The Tree
 
Joined: Dec 2002
Posts: 176
Likes: 0
From: Orlando, FL
Default Re: PCM "Unlearned"???

Is COTs disabled or enabled? Also, did they take the time ensure the LTrims would remain negative?

Tim
Reply
Old Feb 4, 2003 | 10:39 AM
  #4  
Dave@Ramchargers's Avatar
Launching!
 
Joined: Sep 2002
Posts: 238
Likes: 0
From: Warren, mi
Default Re: PCM "Unlearned"???

i had my car dyno tuned and the next day the air fuel was all over the place.. I forgot to uninstall my HPP untill i got there. It had to be re tuned because the car learned over time.. has it done a second time and i was all set.

<small>[ February 04, 2003, 10:52 AM: Message edited by: Dave@Ramchargers ]</small>
Reply




All times are GMT -5. The time now is 04:43 AM.

story-0
10 Reasons Daily Driving a Swap Project SUCKS! (& 1 Reason to Do It Anyway)

Slideshow: 10 reasons daily-driving a swap project might not be for you. Or is it?

By Michael S. Palmer | 2026-06-17 09:39:05


VIEW MORE
story-1
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-09 14:55:56


VIEW MORE
story-2
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-06-18 10:26:23


VIEW MORE
story-3
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-4
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-5
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-6
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-7
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-8
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-9
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE