diablo question

**02BURBAN** · 11-28-2007, 12:31 PM

THE TUNER AT THE DYNO SHOP SAID HE WAS GOING TO RUN THE SUBBURBAN LEAN....
MONITORING DATA....
30% ENGINE LOAD
0% STFT
10.8% LTFT
12.6 - 13.2 MAF
27* SPARK
3* TO 0* KNOCK
75 MPH
75% TPS
177* ENGINE TEMP.

DOES ANY ONE KNOW IF IT SOUNDS WRIGHT... THE TRUCK IS 2002 SUBURBAN Z-71...

**0rion** · 11-28-2007, 04:52 PM

I can't really tell what you're showing me there. That's data from a log? 3 degrees knock? LTFT's 10% lean? If that's accurate it looks a little lean to me. Really need a wideband to see what the true afr is. What's your WOT data look like? What mv's are your O2's at and are you seeing knock at WOT?

**The Silver Goat** · 11-29-2007, 01:02 AM

Based on info from other web sites your LTFT's should be between -5% & +5%.
Your tuner is definitely running the vehicle lean.

Your PCM is adding 10% more fuel to get to 0%...
Your PCM will always chase 0% or the perfect A/F ratio

**02BURBAN** · 11-29-2007, 07:18 AM

The Shop Did Use A Wide Band 02 Sensor Hooked At The End Of The Tail Pipe. I Can Not Remeber But I Belive My 02 Sensors Are Running From 680 To 730 Not The 890 To 930 Like I Have In The Tunning Threads... The 3 Deg Would Only Show When Speeding Up Then It Will Go Back To Zero... As Long As The Speed Is Maintained The Eng. Knock Will Show 0.... What I Do Know Is When The Tuner Ran The Frist Dyno Pull, A Guy Who Goes To His Shop Pulled Up To The Truck And Said The Headers Were A Little Red While Running The Pull And It Was Too Lean... He Answered The Wide Band Is Showing Good On The Chart... Could It Be The Truck Is To Lean And The 02 Are Not Showing What They Need To Show... Could That Be The Lack Of Power From 500 Rpm To 2,000 Rpms... From 2,000 To 5,000 The Truck Runs Strong And Would Like To Get An Even Pull Through The Entire Rpm Range...

**0rion** · 11-29-2007, 02:00 PM

I would get it retuned.

**02BURBAN** · 11-30-2007, 05:56 AM

Last Night I Warmed Up The Truck Good And Made Some Wot While Monitoring Data... I Did Ad The P/p Tb Last Week End And My Tune Was 3 Months Ago... Will It Be Ok To Start Moving Around With The Diablo Tuner...
3*> 0*knock It Will Go Back To 0* But Some Times While Speeding Up It Will Show No More Than 3*...
24.8 Spack Adv. @ 3,000 Rpm... Appr. 90+mph..
680 To Max 800 02 Sensors...they Move Around A Lot...
Air Temp. Is Cooler Also If It Has Any To Do...
I WOULD LIKE TO KOWN IF YOU GO IN TO TUNE IT DOES IT CHANGE ANY THING OR CAN YOU GO AND SEE WHAT THE SETTING ARE...

**02BURBAN** · 11-30-2007, 06:47 AM

I Call The Tuner This Morning And Asked About The 10.8 Ltft And That I Had Add A P/p Tb... He Said It Was To High To Add Fuel To Where It At +3 To +5% On The Ltft And He Also Said The Spark Sound Good... I Will Try To Make The Change This Evening And See What Good This Does...
Thanks Guys For The Replys...
Will It Be Better To Try To Get It Closer To 0% At Wot Or Is It Fine +3 To +5 %ltft... I Am Guessing This Is Still Tring To Run It Lean Like He Frist Set The Truck To "maybe"...

**0rion** · 11-30-2007, 09:36 AM

you want the LTFT's to lock at zero during wot. That's why you add fuel at part throttle because let's say it's +10% right before you go WOT then it'll add that 10% to your WOT AFR. It just lets you get the WOT AFR consistent. I would add fuel to part throttle and log it until you get your LTFT's right then log some WOT runs and get your WOT O2 voltages 880-890 with zero knock. I wouldn't worry about the knock right now until you get your AFR straight because that's probably what's causing it. Sounds like you're pretty lean.

There are just tons of info out there on tuning with the diablo. It's not real hard as long as you understand what you're seeing in the data.

**02BURBAN** · 11-30-2007, 10:30 AM

O.k. That Make Sense And Will Adjust My Fuel And Give It A Test Run....
Tanks....

**aeroengineer** · 12-01-2007, 04:19 AM

Originally Posted by 0rion

you want the LTFT's to lock at zero during wot. That's why you add fuel at part throttle because let's say it's +10% right before you go WOT then it'll add that 10% to your WOT AFR. It just lets you get the WOT AFR consistent. I would add fuel to part throttle and log it until you get your LTFT's right then log some WOT runs and get your WOT O2 voltages 880-890 with zero knock. I wouldn't worry about the knock right now until you get your AFR straight because that's probably what's causing it. Sounds like you're pretty lean.

There are just tons of info out there on tuning with the diablo. It's not real hard as long as you understand what you're seeing in the data.

Agreed. Consider pulling some timing until you get the A/F ratio accurate across the table.

**02BURBAN** · 12-01-2007, 04:29 AM

Ok Here What I Look At The Settings...
Pe
2k>4k 14%
4k>7k 13%

Spark
1k>1.8k 5% Adv.
Wot 2k>4k 14% Adv.
Wot 4k>7k 9% Adv.

Would Both % On The Pe Have To Come Down Or How Is This Done...
Cloud I Avd. The Spark Some...
Please Help....

**The Silver Goat** · 12-02-2007, 02:56 AM

Originally Posted by 02BURBAN

Ok Here What I Look At The Settings...
Pe
2k>4k 14%
4k>7k 13%

Spark
1k>1.8k 5% Adv.
Wot 2k>4k 14% Adv.
Wot 4k>7k 9% Adv.

Would Both % On The Pe Have To Come Down Or How Is This Done...
Cloud I Avd. The Spark Some...
Please Help....

Changing the PE will not balance the LTFT's.
LTFT are cruising around and WOT is exactly that...

Use the Injector Slope to balance your LTFT's
For whatever % you are (+) or (-) you change the Injection Slope inversely.
The formula has an inverse relationship. (-) adds more fuel: holding the injector open longer thus adding more fuel. (+) is reverse. Its set up this way so if you change injector size... Most mods require bigger injectors.

So, if you (+) 10% change the slope injection to (-) 9% and no need for re-learn. This change is instant. You can tweak as necessary.

Get this portion of the tune straighten out first. Then you can change the timing and fuel. 5% advance on the timing ='s approx. 1 degree of timing: that's the ratio. Add fuel as required to avoid a lean condition. Adding fuel will reduce the PCM monitoring relative to Knock and retarding the timing.

**02BURBAN** · 12-02-2007, 04:45 AM

OK , I GET IT... GO DOWN TO THE INJECTOR SLOP AND REDUCE +10 TO - 9.
STORE IT AND THE TEST RUN TO TRUCK UNTILL I GET MY LTFT'S TO READ 0 AT WOT AND GET THE 02 BETWEEN 880 - 890 WITH ZERO KNOCK...
THANKS THAT IS A BIG HELP THERE FELLOWS...

I WILL MOVE THIS THIS EVENING... I GOT TO WORK TO DAY AND EVERY DAY....

**The Silver Goat** · 12-02-2007, 05:17 AM

Originally Posted by 02BURBAN

OK , I GET IT... GO DOWN TO THE INJECTOR SLOP AND REDUCE +10 TO - 9.
STORE IT AND THE TEST RUN TO TRUCK UNTILL I GET MY LTFT'S TO READ 0 AT WOT AND GET THE 02 BETWEEN 880 - 890 WITH ZERO KNOCK...
THANKS THAT IS A BIG HELP THERE FELLOWS...

I WILL MOVE THIS THIS EVENING... I GOT TO WORK TO DAY AND EVERY DAY....

I did not recall seeing a setting for the Injector Slope in the previous posts and
this is not at a WOT test run - this is for cruising along at 55 MPH

To clarify: if LTFT = +10% you reduce your Injector Slope by -9% give or take 1% to get your LTFT to 0%.
Once you get the LTFT in balance, then you commence with WOT test runs.
Advance the timing and add fuel as needed to avoid the knock response from PCM...
Work the low end banks first (2,000 to 4000 RPM) - thats the getting you out of the hole.
The focus on the 4000 to 7000 bank to sustain power across the entire RPM range.
It's all about torque
TO further make this a challenge you could achieve a -1% to -2% on your LTFT. This means the PCM is reducing the fuel by the aforementioned amount. It's always better to run a hair rich...

It took me a while to figure this all out and I've yet to dyno mine. But at least I know I'm running it within safe parameters.

At the end of the day I'm taking my to a local tune shop who uses LS1 edits.
That will be a tune to talk about...

**02BURBAN** · 12-02-2007, 07:08 AM

Ok I Will Try This So I Get My Ltft's Level And Test Run To See What It's Showing... I Hope I Get The Diablo Out Of The Preditor....
Thanks...

**02BURBAN** · 12-03-2007, 05:11 AM

I Check What The Injector Slop Was Set At 0... I Moved It To -8 And It Got Dark Very Quick With Rainny Wheather So I Did Not Run The Truck In The Hwy... I Have Another Question Why Does The Stft And The Ltft Very With The A/c... Is It Good To Adjust With A/c Off Or On... I Beleive I Will Have To Bring It Down To A -4 But I Need To Make Some Hwy Runs To Get Every Thing Nice And Warm... The Truck Will Brake The Tires Know But Still Has Some Knock To It... Will Clear Back To 0 Knock But It Did Show Some Knock... I Will Continue To Work It Untill I Get It Wright... There Was Some Gain Thought Because That Suburban Has Never Been Able To Brake The Tires Even When It Was New...

**The Silver Goat** · 12-03-2007, 02:28 PM

Originally Posted by 02BURBAN

I Check What The Injector Slop Was Set At 0... I Moved It To -8 And It Got Dark Very Quick With Rainny Wheather So I Did Not Run The Truck In The Hwy... I Have Another Question Why Does The Stft And The Ltft Very With The A/c... Is It Good To Adjust With A/c Off Or On... I Beleive I Will Have To Bring It Down To A -4 But I Need To Make Some Hwy Runs To Get Every Thing Nice And Warm... The Truck Will Brake The Tires Know But Still Has Some Knock To It... Will Clear Back To 0 Knock But It Did Show Some Knock... I Will Continue To Work It Untill I Get It Wright... There Was Some Gain Thought Because That Suburban Has Never Been Able To Brake The Tires Even When It Was New...

The engine is under a different load with the A/C running.

Run the vehicle without any accessories when working to true up LTFT's.
STFT are instant adjustments the PCM is making to obtain the proper A/F ratios.

Take my advice and adjust your slope to (-)10. You should your LTFT balance out to 0% which is where you want to be...

If you the Diablo tune loaded return all the changes back to '0'.
Once you get the LTFT's to 0% or a minus (-)1% you can then begin to change the timing and then adjust the fuel.

I have modified my MAF to allow for more air. Thus I'm currently set at (-) 15% adding more fuel. My LTFT's are 0%.

I've added 5% on both banks (2000 - 4000 RPM) and (4000-7000RPM to the and have not added more fuel during WOT. Each case is different. Given the weight of your vehicle you may need to add fuel during WOT, but as you know you do not want knock.

**02BURBAN** · 12-05-2007, 07:47 AM

Last Night I Was Monitoring Data And Got The Truck On A Smooth Roll And Was Travaling 61 On A 55 And There Was A Red White And Blue At The Bottom Of The Over Pass... He Waited For Me To Make The Light And Here He Comes... Well I Have A Yellow Slip Now... I Have To Find A Nice Open Road To Let Is Cruz And Try Wot...

**02BURBAN** · 12-06-2007, 06:08 AM

Thanks For The Info Will Try This As Soon As I Get The Red White And Bules Off My Tail... Got A Yellow Slip With A 61 On 50 Mph... No Good....

**02BURBAN** · 12-09-2007, 04:42 AM

PE 2K>4K 14%
4K>7K 13%
SPARK 1K>1.8k 5%
WOT 2k>4k 10%
WOT 4k>7k 6%
INJECTOR SLOP -10%

REAL TIME DATA

177* ENG. TEMP.
-2 STFT
-1.5LTFT
0.5 TO 1.2 % KNOCK @WOT ONLY THEN CLEARS TO 0...
890 TO 905 02 SENSORS...

LOST A LITTLE POWER BY BACK OFF THE TIMING BUT I WAS GETTING TO MUCH KNOCK WHEN I CHANGE TO INJECTOR SLOP TO -10%... I WAS SHOWING 6% OF KNOCK BEFORE IT WILL CLEAR UP. DO THIS SETTING SHOW GOOD. CAN I PUSH IT A LITTLE MORE ON ANY OF THE SETTINGS OR IS THIS THE LIMIT...

THANKS IN ADVANCE FELLOW IT BEEN A GRAET HELP.....