PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

FI tuning - timing and afr

Thread Tools
 
Search this Thread
 
Old Apr 8, 2012 | 10:17 PM
  #1  
273sunsetZ's Avatar
Thread Starter
10 Second Club
 
Joined: Aug 2005
Posts: 567
Likes: 0
From: Tennessee Tech
Default FI tuning - timing and afr

I've been tuning on my car all weekend and just noticed today that its seeing 2* of kr at part throttle acceleration of no more than 145kpa. It will go up to 2* at first and then works its way to 0.

My question, is there a general rule as to what afr and timing needs to be, at part throttle? I'm thinking this might have something to do with it since I've botched the timing table up so many times in the past when I was running nitrous. I've thought about just starting with a stock timing & Ve table and going from there but i've put a lot of time into the drive ability tune of this car, and have never seen kr before unless it was @ wot. Any advice?
Reply
Old Apr 8, 2012 | 10:20 PM
  #2  
273sunsetZ's Avatar
Thread Starter
10 Second Club
 
Joined: Aug 2005
Posts: 567
Likes: 0
From: Tennessee Tech
Default

More info:

Front mount pte 76
346 ci
Total commanded WOT timing 14*
Reply
Old Apr 8, 2012 | 10:37 PM
  #3  
gectek's Avatar
TECH Enthusiast
iTrader: (2)
 
Joined: Jun 2008
Posts: 702
Likes: 0
Default

The better info would be the log and tune. I have stressed this in quite a few other threads, but are you sure its actual knock? It could be burst knock since you said it goes away so fast. You can log that and see what is going on.
Reply
Old Apr 9, 2012 | 02:11 AM
  #4  
273sunsetZ's Avatar
Thread Starter
10 Second Club
 
Joined: Aug 2005
Posts: 567
Likes: 0
From: Tennessee Tech
Default

i've attached the files. let me know if you find anything. Part throttle and driving around it's fine but when I stab the peddal there is hesitation, afr skyrockets and so on... so this is the log where I kept trying to create the issues so i could see what kpa, rpm, afr, and timing were at when it happened, i think it shows a total of 1.7* KR during part throttle acceleration and i never get over 50% tp, i believe timing ended up going down to 10* but to be honest i have no idea what this number should be during part throttle??? I'm waiting for a new IAT sensor to come in so set everything in the table to 0, but never had any issues before with the iat pulling timing. Generally, i know how to tune for WOT by BE, VE, and timing tables and have never seen any knock at wot, it always shows what it commanded, which is 14* and afr in the mid 11's but this part throttle issue is a first, i've been driving this car for about 7 months and never noticed it.

I recently changed the fuel setup from factory lines, regulator, 80lb's to -8 feed, fast rails, brfpr, and return.
Attached Files
File Type: hpl
KR_issue.hpl (125.3 KB, 78 views)
Reply
Old Apr 9, 2012 | 02:39 AM
  #5  
gectek's Avatar
TECH Enthusiast
iTrader: (2)
 
Joined: Jun 2008
Posts: 702
Likes: 0
Default

So you have the maf turned off in the diag tables, but adding fuel? Are you speed density? Open loop speed density? Since your long terms are off, your short terms are off all the codes are erased.

Is there a reason you are doing it this way? How high does the car really idle at?

Honestly your VE table has some bad transitions in it. And your spark table as well. I think your PE is not coming on soon enough with boost and you are running into a problem of an overlean followed by overly rich condition. Esp if you look at the eq ratio. Your pulse width skyrockets out of nowhere with your normal transition. I am not seeing any MPH so its hard to tell. Both are zero. You still running the 4L60?
Reply
Old Apr 9, 2012 | 05:39 PM
  #6  
273sunsetZ's Avatar
Thread Starter
10 Second Club
 
Joined: Aug 2005
Posts: 567
Likes: 0
From: Tennessee Tech
Default

Originally Posted by gectek
So you have the maf turned off in the diag tables, but adding fuel? Are you speed density? Open loop speed density? Since your long terms are off, your short terms are off all the codes are erased.

Is there a reason you are doing it this way? How high does the car really idle at?

Honestly your VE table has some bad transitions in it. And your spark table as well. I think your PE is not coming on soon enough with boost and you are running into a problem of an overlean followed by overly rich condition. Esp if you look at the eq ratio. Your pulse width skyrockets out of nowhere with your normal transition. I am not seeing any MPH so its hard to tell. Both are zero. You still running the 4L60?
I had a partial tune put on it last year. i'm not sure what all he changed and to be honest i have no idea how it should be. I am only running a wideband out of the downpipe which dumps at the front passenger tire, I really need to get a bung welded into each side of the crossover pipe for the 02's but just havnt had time. The car idles right at 1k, it has a pretty healthy cam and much lower than that will cut off when i put it in gear. I'm running a th350
Reply




All times are GMT -5. The time now is 02:09 PM.

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