PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Why are my STIT's staying at zero?

Thread Tools
 
Search this Thread
 
Old Aug 20, 2010 | 01:48 PM
  #1  
JimMueller's Avatar
Thread Starter
TECH Veteran
20 Year Member
Liked
Loved
Community Favorite
iTrader: (9)
 
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
Default Why are my STIT's staying at zero?

HPT Support says it's either mechanical or in the tune. Frost is helping me with the tune and it's the first time he's seen this.

I'm going to try scanning with the 2.22 release instead of the beta in case it's a scanner bug. If it's not that, how do I resolve this?
Reply
Old Aug 20, 2010 | 02:23 PM
  #2  
edcmat-l1's Avatar
Banned
iTrader: (10)
 
Joined: Jul 2006
Posts: 4,782
Likes: 4
From: Va Beach
Default

What are your O2 sensors reading? What codes are set? What codes are turned off? If the PCM sees funky stuff going on with O2 oscillation, it will discontinue closed loop operation.
Reply
Old Aug 20, 2010 | 03:38 PM
  #3  
Frost's Avatar
FormerVendor
iTrader: (45)
 
Joined: Jul 2005
Posts: 5,913
Likes: 2
From: Richmond VA
Default

Originally Posted by edcmat-l1
What are your O2 sensors reading? What codes are set? What codes are turned off? If the PCM sees funky stuff going on with O2 oscillation, it will discontinue closed loop operation.
They would update early on in the process and no DTC's have been changed since. The issue is STIT's, not STFT's. It's pretty strange!
Reply
Old Aug 20, 2010 | 03:54 PM
  #4  
edcmat-l1's Avatar
Banned
iTrader: (10)
 
Joined: Jul 2006
Posts: 4,782
Likes: 4
From: Va Beach
Default

Originally Posted by Frost
They would update early on in the process and no DTC's have been changed since. The issue is STIT's, not STFT's. It's pretty strange!
OOPs! Misread.......

I had one one time that the STITs would lock in on the lowest base airflow number. Wouldn't reset to zero off idle. Never figured it out. Had to "tune around" it.
Reply
Old Aug 20, 2010 | 04:15 PM
  #5  
jimmyblue's Avatar
Moderator
iTrader: (11)
 
Joined: Mar 2002
Posts: 12,604
Likes: 7
From: East Central Florida
Default

There are some enable fields for adaptive idle RPM, like
off temperature. And if your TPS reads out of idle range
then it won't even try to trim. Any of this sound likely?

If IAC counts are moving around and RPM is being held,
I'd be thinking a PID screwup of some sort (what it thinks
is your STIT PID, returns zeroes). There seem to be some
occasional issues of that sort, though you'd think a '98
F-body ought to be a pretty known quantity. Then again
there's that (how many?) multiple-OSes deal....
Reply
Old Aug 20, 2010 | 05:36 PM
  #6  
foff667's Avatar
LS1TECH Sponsor
iTrader: (2)
 
Joined: Jul 2003
Posts: 7,986
Likes: 3
From: Clermont, FL
Default

Try logging 24 bytes or less.
Reply
Old Aug 20, 2010 | 07:05 PM
  #7  
JimMueller's Avatar
Thread Starter
TECH Veteran
20 Year Member
Liked
Loved
Community Favorite
iTrader: (9)
 
Joined: Jan 2002
Posts: 4,072
Likes: 75
From: Casselberry FL
Default

I'll try that this weekend. My opinion is the software should notify the user if you're trying to log more than the supported number of bytes when you connect to the vehicle. I'm also curious how the software determines which bytes to ignore?
Reply




All times are GMT -5. The time now is 08:56 PM.

story-0
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 | 2026-05-28 11:05:11


VIEW MORE
story-1
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-2
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-3
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-4
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-5
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-6
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-7
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
story-8
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-9
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE