LTFT????

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Jan 25, 2003 | 11:11 PM

sconnor

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From: Baltimore, MD

LTFT????

I'm trying to get my car tuned properly and I need to know were I need to have my LTFT. And which bank should I look at 1 or 2. I also can't seem to get my WOT above 11.9. I have my MAFT set at 4% lean now should I go more? TIA ....Scott

Jan 26, 2003 | 11:53 AM

Doc99SShome

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From: Newport, Michigan

Re: LTFT????

With any scanner, you can begin to look at LTFTs from both banks, 1 and 2. 1 is driver side, 2 is passenger side. In a perfect world, they would be identical. But since, the engine is not truely symmetrical and O2 sensor are different (and other reasons), the bank 1 LTFT value will almost never be the same as the bank 2 LTFT value.

Another complication is that there are several LTFTs, one for each fuel cell, there are (I think) about 22 fuel cells.. I think 19 is for idle, 22 is for WOT, 21 is for decel.

Now about your MAFT, there are at least two dial switches inside the case, Mine had 2, one for base (part throotle operation), and one for WOT.
You state that you are at 4% lean, which one are you talking about???
You can effect the WOT AFR with adjustments with both switches, base and WOT!!!!! Believe it or not.

Jan 26, 2003 | 01:18 PM

The Dragon

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From: Tampa, Florida

Re: LTFT????

Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly.

Jan 26, 2003 | 02:12 PM

J&JsTA

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From: Whitby Ont Canada

Re: LTFT????

<blockquote>quote:<hr />Originally posted by The Dragon:
 Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly. <hr /></blockquote>One day I would love to get a definative answer on fuel cell monitoring.

Here's another answer from a search in LS1.com

-------------------------------------------------
Here are some things I have learned so far:

Cell definitions, courtesy of TeamZR1:

Non load cells 0-5, 21
Idle 17-20
Part Throttle 6-14
WOT 15, 22
-------------------------------------------------

If I was to continue to read there are a couple more variations..... <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> some one needs to post a GM tech site that lists what the REAL cells are and stop the confusion SHEESH <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Jan 26, 2003 | 09:57 PM

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by Doc99SShome:
 With any scanner, you can begin to look at LTFTs from both banks, 1 and 2. 1 is driver side, 2 is passenger side. In a perfect world, they would be identical. But since, the engine is not truely symmetrical and O2 sensor are different (and other reasons), the bank 1 LTFT value will almost never be the same as the bank 2 LTFT value.

Another complication is that there are several LTFTs, one for each fuel cell, there are (I think) about 22 fuel cells.. I think 19 is for idle, 22 is for WOT, 21 is for decel.

Now about your MAFT, there are at least two dial switches inside the case, Mine had 2, one for base (part throotle operation), and one for WOT.
You state that you are at 4% lean, which one are you talking about???
You can effect the WOT AFR with adjustments with both switches, base and WOT!!!!! Believe it or not. <hr /></blockquote>Currently I have it set on 5% rich at idle and 4% lean on WOT.....Scott

Jan 26, 2003 | 09:59 PM

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by The Dragon:
 Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly. <hr /></blockquote>I am kinda new to A-Tap, how do I log the LTFT's.....Scott

Jan 27, 2003 | 12:31 AM

J&JsTA

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From: Whitby Ont Canada

Re: LTFT????

From Understanding the GENIII LS1/LS6 Control Systems and PCM

Fuel Cells

The PCM will move from cell to cell under varying conditions.
There are 22 Fuel Cells, and are as follows:

1-19 – used to update fuel trims
20 – Idle Cell
21 – Deceleration Cell
22 – WOT (Power Enrichment mode)

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Jan 27, 2003 | 01:22 AM

The Dragon

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From: Tampa, Florida

Re: LTFT????

<blockquote>quote:<hr />Originally posted by J&JsTA:
 <blockquote>quote:<hr />Originally posted by The Dragon:
 Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly. <hr /></blockquote>One day I would love to get a definative answer on fuel cell monitoring.

Here's another answer from a search in LS1.com <hr /></blockquote>The answer is simplicity in itself: go out and sit at idle in neutral --->>> 19. Click the A/C or defroster on while still in neutral --->>> 18.
Decelerate in gear (eg. foot off of accelerator without braking) and you get 0's/1's etc.
Part throttle acceleration in any gear and you get 4's, 9's, 12's, etc.
WOT --->>> 22 ONLY.

<blockquote>quote:<hr />Originally posted by sconnor:
 I am kinda new to A-Tap, how do I log the LTFT's.....Scott <hr /></blockquote>Connect to your car with Atap. Go to Gauges in Atap and record your Long Term Fuel Trim Bank 1 and Bank 2 (LTFT B1, LTFT B2), and Fuel Cell Trim (these parameters are in Atap).
Drive around town for a while eg. 20 - 30 minutes. Switch gears normally.
Stop recording. Open that log up in playback mode. Go to Log and click export to comma delimited file. This will export your log to Excel or whatever you use. When this is done, close out of Atap and open the Excel log file.

Delete any column that does not contain Fuel Cells 4 thru 16.
Average the remaining LTFT's.
<img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Jan 27, 2003 | 06:59 AM

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by The Dragon:
 <blockquote>quote:<hr />Originally posted by J&JsTA:
 <blockquote>quote:<hr />Originally posted by The Dragon:
 Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly. <hr /></blockquote>One day I would love to get a definative answer on fuel cell monitoring.

Here's another answer from a search in LS1.com <hr /></blockquote>The answer is simplicity in itself: go out and sit at idle in neutral --->>> 19. Click the A/C or defroster on while still in neutral --->>> 18.
Decelerate in gear (eg. foot off of accelerator without braking) and you get 0's/1's etc.
Part throttle acceleration in any gear and you get 4's, 9's, 12's, etc.
WOT --->>> 22 ONLY.

<blockquote>quote:<hr />Originally posted by sconnor:
 I am kinda new to A-Tap, how do I log the LTFT's.....Scott <hr /></blockquote>Connect to your car with Atap. Go to Gauges in Atap and record your Long Term Fuel Trim Bank 1 and Bank 2 (LTFT B1, LTFT B2), and Fuel Cell Trim (these parameters are in Atap).
Drive around town for a while eg. 20 - 30 minutes. Switch gears normally.
Stop recording. Open that log up in playback mode. Go to Log and click export to comma delimited file. This will export your log to Excel or whatever you use. When this is done, close out of Atap and open the Excel log file.

Delete any column that does not contain Fuel Cells 4 thru 16.
Average the remaining LTFT's.
<img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" /> <hr /></blockquote>Thanks for the quick reply!!! I am going to be doing it first thing this morning.....Thanks Scott

Jan 27, 2003 | 02:35 PM

#10

The Dragon

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From: Tampa, Florida

Re: LTFT????

<blockquote>quote:<hr />Originally posted by sconnor:
 <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" /> Thanks for the quick reply!!! I am going to be doing it first thing this morning.....Thanks Scott <hr /></blockquote><img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Jan 27, 2003 | 04:58 PM

#11

WS6 GreeN

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From: Birmingham, AL

Re: LTFT????

Don't count on your A/F ration showing more than 11.9 in ATAP <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> I haven't had any luck with that yet. They say you should only pay attention to your O2 sensors at WOT anyway.

Jan 27, 2003 | 05:54 PM

#12

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by WS6 GreeN:
 Don't count on your A/F ration showing more than 11.9 in ATAP <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> I haven't had any luck with that yet. They say you should only pay attention to your O2 sensors at WOT anyway. <hr /></blockquote>I can't get it lower thean 11.9:1 at WOT....

Jan 28, 2003 | 11:43 AM

#13

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by sconnor:
 <blockquote>quote:<hr />Originally posted by The Dragon:
 <blockquote>quote:<hr />Originally posted by J&JsTA:
 <blockquote>quote:<hr />Originally posted by The Dragon:
 Scott, take a long autotap log and average both passenger and driver-side Lterms when they are in fuel cells 4 - 16.
Your WOT Lterms should go to 0 once you've gotten your cruising Lterms (those that appear in 4-16 cells) negative. After you've made a BASE adjustment, remember to give your PCM ~40 learning miles before you tap part-throttle Lterms again. Try and get them around -1.
Always tune your BASE MAFT, or cruising/part-throttle, first; then log your WOT and adjust WOT settings accordingly. <hr /></blockquote>One day I would love to get a definative answer on fuel cell monitoring.

Here's another answer from a search in LS1.com <hr /></blockquote>The answer is simplicity in itself: go out and sit at idle in neutral --->>> 19. Click the A/C or defroster on while still in neutral --->>> 18.
Decelerate in gear (eg. foot off of accelerator without braking) and you get 0's/1's etc.
Part throttle acceleration in any gear and you get 4's, 9's, 12's, etc.
WOT --->>> 22 ONLY.

<blockquote>quote:<hr />Originally posted by sconnor:
 I am kinda new to A-Tap, how do I log the LTFT's.....Scott <hr /></blockquote>Connect to your car with Atap. Go to Gauges in Atap and record your Long Term Fuel Trim Bank 1 and Bank 2 (LTFT B1, LTFT B2), and Fuel Cell Trim (these parameters are in Atap).
Drive around town for a while eg. 20 - 30 minutes. Switch gears normally.
Stop recording. Open that log up in playback mode. Go to Log and click export to comma delimited file. This will export your log to Excel or whatever you use. When this is done, close out of Atap and open the Excel log file.

Delete any column that does not contain Fuel Cells 4 thru 16.
Average the remaining LTFT's.
<img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" /> <hr /></blockquote>Thanks for the quick reply!!! I am going to be doing it first thing this morning.....Thanks Scott <hr /></blockquote>I logged the LTFT's yesterday deleted all the cells that werenot between 4,16 and averaged them out. My grand average for bank 1 is 2.01, and my grand average for bank 2 is 0.98. Should I adjust the richness on idle another notch or is this good?? TIA...Scott

Jan 28, 2003 | 01:53 PM

#14

The Dragon

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From: Tampa, Florida

Re: LTFT????

<blockquote>quote:<hr />Originally posted by sconnor:
I logged the LTFT's yesterday deleted all the cells that werenot between 4,16 and averaged them out. My grand average for bank 1 is 2.01, and my grand average for bank 2 is 0.98. Should I adjust the richness on idle another notch or is this good?? TIA...Scott <hr /></blockquote>Assuming that your banks are both +, yes.
You need to have them average a negative integer. You're +1.495 now. Click yourself another notch, give it some miles, and tap again <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Jan 28, 2003 | 06:37 PM

#15

sconnor

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From: Baltimore, MD

Re: LTFT????

Jan 29, 2003 | 05:02 PM

#16

sconnor

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From: Baltimore, MD

Re: LTFT????

[/QUOTE]Assuming that your banks are both +, yes.
You need to have them average a negative integer. You're +1.495 now. Click yourself another notch, give it some miles, and tap again <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> [/QB][/QUOTE]
Dude I did it again today, my average for bank 1 is -2.66, and bank 2 is -.3.46. Sorry to keep bothering you with this but it seems like you are the man to talk to about it. Let me ask you this, I have a Granatelli MAF and I need to know if I should turn the switch for the 85mm MAF on or leave it off? Thanks Scott

Jan 29, 2003 | 06:42 PM

#17

Doc99SShome

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From: Newport, Michigan

Re: LTFT????

Just keep it just like it is now. You are perfect for LTFTs now. If you switch something around, you will have to re-dial in the correct base setting for a 85mm MAF to get your LTFTs back to negative.

Because the 85mm MAF comes with different flow frequencies, you should have made a switch in the first place. But you are OK now, so leave it alone. I never change a switch when I tuned my MAFT when I had my GMAF installed.

Now its time to dial in the WOT switch.

Jan 30, 2003 | 12:53 AM

#18

sconnor

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From: Baltimore, MD

Re: LTFT????

<blockquote>quote:<hr />Originally posted by Doc99SShome:
 Just keep it just like it is now. You are perfect for LTFTs now. If you switch something around, you will have to re-dial in the correct base setting for a 85mm MAF to get your LTFTs back to negative.

Because the 85mm MAF comes with different flow frequencies, you should have made a switch in the first place. But you are OK now, so leave it alone. I never change a switch when I tuned my MAFT when I had my GMAF installed.

Now its time to dial in the WOT switch. <hr /></blockquote>Sounds great!!!! Thanks.....Scott

Jan 31, 2003 | 12:31 AM

#19

The Dragon

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Re: LTFT????

If you had Edit, I'd recommend getting them to -1 for best gas mileage but, as Doc said, -3 is fine.

Moving to WOT tuning Baby! <img border="0" alt="[evil]" title="" src="graemlins/gr_devil.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

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