PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Commanded AFR issue please help!

Thread Tools
 
Search this Thread
 
Old Mar 17, 2012 | 03:01 PM
  #1  
Zman420's Avatar
Thread Starter
Staging Lane
iTrader: (18)
 
Joined: Sep 2005
Posts: 67
Likes: 0
From: houston, tx
Default Commanded AFR issue please help!

Finished my heads and cam swap about a week ago. I drove the car over to a friends house and all the afr's were looking good. I just did some minor tweaks to the ve table on the way and everything looked good. It was ideling for awile when all of a sudden the afr's started going lean. I tried adding more and more fuel and it was like it wasn't doing anything to the afr. I limped it home and started checking everything!

Here it is a week later and I have literally gone through it top to bottom. The car runs fine, idles fine, everything is good other then the fact that if I take it out of closed loop the thing just leans out and no matter how much I add to the ve table, it just wont correct it! Even in closed loop, the fuel trims are all over the place (lean). I have tried going into maf only mode and tried correcting the fuel that way to no success.

Im at a loss if solutions at this point and the only other thing I can think of is something in the ecu just let go if that's even possible for one to do this. I have searched and searched for vacuum leaks ect. And no dice.

Is there possibly a ground or something in the ecu that would cause this? any help is greatly appreciated! Has anyone else had a issue like this or am I in a boat by myself here? I have even tried putting the stock tune in and put it in openloop and same scenario.
Fuel pressure is rock solid at 58psi
Reply
Old Mar 17, 2012 | 07:14 PM
  #2  
Zman420's Avatar
Thread Starter
Staging Lane
iTrader: (18)
 
Joined: Sep 2005
Posts: 67
Likes: 0
From: houston, tx
Default

Anyone?
Reply
Old Mar 17, 2012 | 08:52 PM
  #3  
flame's Avatar
TECH Fanatic
20 Year Member
iTrader: (13)
 
Joined: Oct 2004
Posts: 1,169
Likes: 3
From: Waterloo, Ontario
Default

If you were in SD mode and the IAT was really high that will cause it to go lean. It is caused by heatsoak on the IAT sensor.
Reply
Old Mar 17, 2012 | 09:02 PM
  #4  
Zman420's Avatar
Thread Starter
Staging Lane
iTrader: (18)
 
Joined: Sep 2005
Posts: 67
Likes: 0
From: houston, tx
Default

No this happens no matter what IAT it's at.
A link to the log file and tune fiile can be seen here:
http://www.hptuners.com/forum/showthread.php?p=286644
Reply
Old Mar 19, 2012 | 10:43 PM
  #5  
joecar's Avatar
TECH Senior Member
20 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Default

Is it working now...?
Reply
Old Mar 21, 2012 | 09:12 PM
  #6  
Phil'sC5vette's Avatar
TECH Fanatic
iTrader: (4)
 
Joined: Feb 2004
Posts: 1,074
Likes: 0
From: Tampa
Default

dial in your MAF

In HP tuners histograms, set up your MAF to determine the commanded AFR and the percent you are off from the commanded.
Reply




All times are GMT -5. The time now is 07:18 AM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE