LTFT troubles and injectors 42's
08-12-2006, 10:17 AM
#1
LTFT troubles and injectors 42's After installing 42lb svo injectors, I used the spreed sheet, I know can't seem to get my ltft's in order. Seems to hesitate/stumble slightly (once in a while) also and my 1/4 times have gone to hell. I lost my log from last night, so... Also, added racetronics pump at same time.
On the injectors, I used the known numbers on red hard's site and compared to spread sheet are very close. Am I missing another step, like min pulse width? or something else?
On the trims, I logged and was into postives on all cells, and higher like 12/15% in the lower flow areas and all way to 4000rpm. Now, what I did was add these with special paste and it seems to make the trims worse, more positive. However, when running with maf disable they are great in the low negatives, just where i want them, but when i plugged the MAF in they jump to like 25 postive now. Tried this a couple times with same results?
Also, am getting a PO449 code which is the valve at the charcol fuel canister. Seems to be on/off and I get the code to clear if I turn it on/off a few times in HPT. Chevy dealer mech said this has no bearing on performance? But it seems to stumble sometimes when switching it around to get it off?
I know there is a couple issues here, and I am driving myself crazy on this so I thought I would check with the tuning GURUs. Thanks, and I'll help ya guys with your nitorus stuff anytime in exchange.
Robert
On the injectors, I used the known numbers on red hard's site and compared to spread sheet are very close. Am I missing another step, like min pulse width? or something else?
On the trims, I logged and was into postives on all cells, and higher like 12/15% in the lower flow areas and all way to 4000rpm. Now, what I did was add these with special paste and it seems to make the trims worse, more positive. However, when running with maf disable they are great in the low negatives, just where i want them, but when i plugged the MAF in they jump to like 25 postive now. Tried this a couple times with same results?
Also, am getting a PO449 code which is the valve at the charcol fuel canister. Seems to be on/off and I get the code to clear if I turn it on/off a few times in HPT. Chevy dealer mech said this has no bearing on performance? But it seems to stumble sometimes when switching it around to get it off?
I know there is a couple issues here, and I am driving myself crazy on this so I thought I would check with the tuning GURUs. Thanks, and I'll help ya guys with your nitorus stuff anytime in exchange.
Robert
08-12-2006, 01:42 PM
#2
TECH Fanatic
iTrader: (10)
Join Date: Aug 2004
Location: Rochester,Ny
Posts: 1,433
Likes: 0
Received 0 Likes
on
0 Posts
it seems you MAF may not be agreeing with your VE table.When mine were to far apart it would stumble...Try doing the ve table then MAF table to match it..What year is your car and what are you using to tune it??
08-12-2006, 01:45 PM
#3
TECH Fanatic
iTrader: (10)
Join Date: Aug 2004
Location: Rochester,Ny
Posts: 1,433
Likes: 0
Received 0 Likes
on
0 Posts
Never mind i saw your sig...Are you using the wideband or the stock narrowbands to tune it...What i did was use the wideband to get in the general area for part throttle then used the stock o2 sensors to fine tune the part throttle,because the computer is looking at your stock o2 sensors and not the wideband...The use the wideband only for WOT..
08-12-2006, 02:53 PM
#5
TECH Enthusiast
iTrader: (14)
Join Date: Apr 2005
Location: NE Ohio
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
Couple of thoughts/suggestions.
1) Double check your fuel line pressure and make sure it agrees with the numbers being plugged into the spreadsheet.
2) Once fuel parameters are correct dial in your VE like you would normally.
3) After VE is dialed in use VE calculated airflow values to adjust your MAF.
In short, if your LTFTs are significantly better with the MAF disabled, then either there's an issue with the data the MAF is reporting, or it's calibration is significantly different than your VE table.
Any other changes besides the 42lbs injectors and the fuel pump?
1) Double check your fuel line pressure and make sure it agrees with the numbers being plugged into the spreadsheet.
2) Once fuel parameters are correct dial in your VE like you would normally.
3) After VE is dialed in use VE calculated airflow values to adjust your MAF.
In short, if your LTFTs are significantly better with the MAF disabled, then either there's an issue with the data the MAF is reporting, or it's calibration is significantly different than your VE table.
Any other changes besides the 42lbs injectors and the fuel pump?
08-12-2006, 03:35 PM
#6
reddtail, MAF was recalibrated before up sizing injectors and seemed fine, again I used the spred sheet and ended up using the truck numbers, IIRC.
As for tuning pt, not sure i follow, it runs with my WB connected at the commanded 14.7 area?
JoeyGC5, yes i cleaned the MAF wires (today and did not help), and MAF was re cal'ed after Air Box install, before injectors and fuel pump.
Muncie21,
1. Fuel line pressure is real close to what it was, at least within a pound or so, I have a pressure gauge to monitor. Pump was added for heavy load nitrous runs, not because stocker was weak at low end.
2. I believe at this point the fuel numbers are correct, I used the 58psi. The same as before.
3. I am not sure how to do this, can you expand your description.
Here's were I am at. I went back a couple bin files to where the injectors were added. Now I am starting over with logging ltft, and am finished with that part. Above the 35 area all trims are 10 postive or more. the rest of the table is within specs. Now this is where I think I may? be having trouble. When logging after setting maf code, i press the relearn trims and reset trims? or like the write up says hit reset trims. Now when I hit reset trims, the button dode not turn color like it goes on, is this normal? When learn is pressed it goes green. directions for this area are not very clear on when and what buttons to push
I am ready to add my positive trims to the VE table. My process, copy all ltft and then use paste-special-add on VE table correct. Then just press relearn and drive for 50 minutes or do we need to push reset again. Please let me know if I am missing something or getting it wrong.
Thanks you guys for taking the time to help out. Mucho gratitude.
Robert
As for tuning pt, not sure i follow, it runs with my WB connected at the commanded 14.7 area?
JoeyGC5, yes i cleaned the MAF wires (today and did not help), and MAF was re cal'ed after Air Box install, before injectors and fuel pump.
Muncie21,
1. Fuel line pressure is real close to what it was, at least within a pound or so, I have a pressure gauge to monitor. Pump was added for heavy load nitrous runs, not because stocker was weak at low end.
2. I believe at this point the fuel numbers are correct, I used the 58psi. The same as before.
3. I am not sure how to do this, can you expand your description.
Here's were I am at. I went back a couple bin files to where the injectors were added. Now I am starting over with logging ltft, and am finished with that part. Above the 35 area all trims are 10 postive or more. the rest of the table is within specs. Now this is where I think I may? be having trouble. When logging after setting maf code, i press the relearn trims and reset trims? or like the write up says hit reset trims. Now when I hit reset trims, the button dode not turn color like it goes on, is this normal? When learn is pressed it goes green. directions for this area are not very clear on when and what buttons to push
I am ready to add my positive trims to the VE table. My process, copy all ltft and then use paste-special-add on VE table correct. Then just press relearn and drive for 50 minutes or do we need to push reset again. Please let me know if I am missing something or getting it wrong.
Thanks you guys for taking the time to help out. Mucho gratitude.
Robert
08-12-2006, 05:23 PM
#7
Yep, redid everything and got all ltft's in plus/minus two. Then when plugging maf back in they go tp positive 8 and mostly above to pos 17. Is my MAF going bad? Also, some new slight bucking single buck just crusing along? Also, can't get my dry spray to perform like in the past, times and mph are way off about 1 sec and 13mph? Man this sucks, ran a good spray time before the injectors? A concident injector install/MAF acting up? Need some insight.
Robert
Robert
Trending Topics
08-13-2006, 12:44 PM
#9
Originally Posted by RedHardSupra
nope, now that you have VE's done, you just need to recalibrate your MAF, shouldn't take more than 10 mins, cop/open road permitting 
post up your tune/logs tho, we need to look over some things
post up your tune/logs tho, we need to look over some things
Robert
08-13-2006, 12:55 PM
#10
no need for MAF spreadsheet anymore, you can do it quite easily with a custom histogram in hpt or efi.
all you need to log is dynair (not dyncylair, they're different!) and the histogram i think is in there already preconfigured for most popular applications, just have to load it, and if it's set up right, you should see it populate values in real-time.
all you need to log is dynair (not dyncylair, they're different!) and the histogram i think is in there already preconfigured for most popular applications, just have to load it, and if it's set up right, you should see it populate values in real-time.
08-13-2006, 01:32 PM
#11
TECH Enthusiast
iTrader: (14)
Join Date: Apr 2005
Location: NE Ohio
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
Robert,
To clarify, what you are going to do is compare dynamic airflow which is in Grams/sec versus Mass Airflow in Hz. You may also want to log Mass Airflow in G/sec. Here's what each does:
Dynamic airflow- is a calculated value based on your (newly corrected) VE table.
MAF Hz- You'll need this as an axis to populate the dyn airflow values against.
Mass Airflow (G/sec)- This shows you the current airflow values from your MAF table.
While driving you can see how far off the MAF table is versus the VE table by looking at the dyn airflow PID vs. the Mass Airflow (g/sec) PID. When you are done setup a histogram showing the dyn airflow vs. MAF in HZ, your table should look like the MAF table in the editor.
When you are driving try to be smooth and avoid sudden transitions. Also, when setting up the historgram shoot for at least 50 cell hits per data points.
This is one way to cal the MAF. I've seen people do it versus AFR error also. So don't think this is the only way to skin this cat.
To clarify, what you are going to do is compare dynamic airflow which is in Grams/sec versus Mass Airflow in Hz. You may also want to log Mass Airflow in G/sec. Here's what each does:
Dynamic airflow- is a calculated value based on your (newly corrected) VE table.
MAF Hz- You'll need this as an axis to populate the dyn airflow values against.
Mass Airflow (G/sec)- This shows you the current airflow values from your MAF table.
While driving you can see how far off the MAF table is versus the VE table by looking at the dyn airflow PID vs. the Mass Airflow (g/sec) PID. When you are done setup a histogram showing the dyn airflow vs. MAF in HZ, your table should look like the MAF table in the editor.
When you are driving try to be smooth and avoid sudden transitions. Also, when setting up the historgram shoot for at least 50 cell hits per data points.
This is one way to cal the MAF. I've seen people do it versus AFR error also. So don't think this is the only way to skin this cat.
08-13-2006, 03:10 PM
#12
You guys have me so looooost, I am ready to jump off a bridge. I have only done the maf cal once and it was not easy at all. Not all are computer/excell type wizards. We need a real world (read: a dummy proff step by step) write for us that are part time want to be tuners, like me.
Sorry to be such a newb to this, but a part time tuner dosen't do it enough to have it down like you guys. Hopefully this will help others. Trying to figure out the two differnt spread sheets has allready taken me a few hours and I still am lost. 
Robert
Robert,
To clarify, what you are going to do is compare dynamic airflow which is in Grams/sec versus Mass Airflow in Hz. You may also want to log Mass Airflow in G/sec. Here's what each does:
Dynamic airflow- is a calculated value based on your (newly corrected) VE table.
MAF Hz- You'll need this as an axis to populate the dyn airflow values against.
Mass Airflow (G/sec)- This shows you the current airflow values from your MAF table.
What pids do I need to log, these above only? Or just make sure they are included with whats in there allready?
While driving you can see how far off the MAF table is versus the VE table by looking at the dyn airflow PID vs. the Mass Airflow (g/sec) PID. When you are done setup a histogram showing the dyn airflow vs. MAF in HZ, your table should look like the MAF table in the editor.
I really don't understand what to do here? how can I see maf table vs VE table, please explain? When done logging, how do i set up a histo showing dyn airflow vs maf hz? Then what do I do with this info? When, where, what do i do to the MAF hz numbers like the spread sheet will do?
When you are driving try to be smooth and avoid sudden transitions. Also, when setting up the historgram shoot for at least 50 cell hits per data points.
Dose this mean how many times each cell is hit as I am logging? if so how do I know?
This is one way to cal the MAF. I've seen people do it versus AFR error also. So don't think this is the only way to skin this cat.
To clarify, what you are going to do is compare dynamic airflow which is in Grams/sec versus Mass Airflow in Hz. You may also want to log Mass Airflow in G/sec. Here's what each does:
Dynamic airflow- is a calculated value based on your (newly corrected) VE table.
MAF Hz- You'll need this as an axis to populate the dyn airflow values against.
Mass Airflow (G/sec)- This shows you the current airflow values from your MAF table.
What pids do I need to log, these above only? Or just make sure they are included with whats in there allready?
While driving you can see how far off the MAF table is versus the VE table by looking at the dyn airflow PID vs. the Mass Airflow (g/sec) PID. When you are done setup a histogram showing the dyn airflow vs. MAF in HZ, your table should look like the MAF table in the editor.
I really don't understand what to do here? how can I see maf table vs VE table, please explain? When done logging, how do i set up a histo showing dyn airflow vs maf hz? Then what do I do with this info? When, where, what do i do to the MAF hz numbers like the spread sheet will do?
When you are driving try to be smooth and avoid sudden transitions. Also, when setting up the historgram shoot for at least 50 cell hits per data points.
Dose this mean how many times each cell is hit as I am logging? if so how do I know?
This is one way to cal the MAF. I've seen people do it versus AFR error also. So don't think this is the only way to skin this cat.
Robert
08-13-2006, 03:21 PM
#14
Originally Posted by RedHardSupra
nope, now that you have VE's done, you just need to recalibrate your MAF, shouldn't take more than 10 mins, cop/open road permitting
post up your tune/logs tho, we need to look over some things
post up your tune/logs tho, we need to look over some things
Robert
08-13-2006, 03:38 PM
#15
TECH Enthusiast
iTrader: (14)
Join Date: Apr 2005
Location: NE Ohio
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
How to setup histogram for MAF calibration Here's a few screen shots of how to setup the dynamic airflow histogram.
Setting up the histogram:
What the histogram should look like when finished and populated. When you get to this point, all you need to do is copy and past the values from this histogram into your MAF airflow table in Editor. You may want to smooth out any bumps or valleys that show up. Finally...keep in mind that these values are only as good as your VE table. If you didn't tune your VE table >4000 RPM (for example) then don't use values from that range, as they won't be valid.
Here's a log of a spirited run. Notice that the dynamic air and MAF PIDs are pretty close to each other. Also, the commanded AFR and the actual AFR are pretty good also.
You only need to log three values (Dynamic Airflow [g/sec], MAF Airflow [g/sec], and MAF Hz [Hz]) to set this up. Keep in mind the more data you are logging the less resolution you'll get.
In closing, I'd like to thank RedHardSupra and all the others on this board for helping me learn this and other tuning details.
Setting up the histogram:
What the histogram should look like when finished and populated. When you get to this point, all you need to do is copy and past the values from this histogram into your MAF airflow table in Editor. You may want to smooth out any bumps or valleys that show up. Finally...keep in mind that these values are only as good as your VE table. If you didn't tune your VE table >4000 RPM (for example) then don't use values from that range, as they won't be valid.
Here's a log of a spirited run. Notice that the dynamic air and MAF PIDs are pretty close to each other. Also, the commanded AFR and the actual AFR are pretty good also.
You only need to log three values (Dynamic Airflow [g/sec], MAF Airflow [g/sec], and MAF Hz [Hz]) to set this up. Keep in mind the more data you are logging the less resolution you'll get.
In closing, I'd like to thank RedHardSupra and all the others on this board for helping me learn this and other tuning details.
Last edited by muncie21; 08-13-2006 at 04:14 PM. Reason: Update with pics
08-13-2006, 05:12 PM
#16
Wow, thanks, I can't believe you went to all that trouble, great. One question is, How i do i get the maf to read correctly in the greater than 4000 range? I will be running a dry shot and need it right on through out range. I have a few values from ltft logging (maf disabled) all the way into 4800rpm and only a few deep. Well this will get me started. Can I re log with maf hooked up again and get into the higher rpms or dose this matter?
Wow, setting up the histogram, i didn't know this was there until recently, must be an add on for the updated software. Been away from tuning to long I guess.
Wow, setting up the histogram, i didn't know this was there until recently, must be an add on for the updated software. Been away from tuning to long I guess.
08-13-2006, 07:05 PM
#17
TECH Enthusiast
iTrader: (14)
Join Date: Apr 2005
Location: NE Ohio
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Robert56
How i do i get the maf to read correctly in the greater than 4000 range?
08-14-2006, 10:42 PM
#18
Man what a great way to do the MAF. Worked flawlessly. My ltft are now 95% between +1 and -3. A couple in the low rpm range are a little more neg, with idle cell being the worse -7/-8. Can I just fine tune these random few cells? like in the VE table, or just leave them alone. Once I get above 4000rpm it just goes flat line all 0, man this is the best I have seen. No more spread sheets for the MAF for me.
Thanks go out to Muncie21 and to RedHardSupra who have both helped in my tuning adventures with great knowledge and insight. There is a little additional info to be added to this post for others doing this and I will add later.
Robert
Thanks go out to Muncie21 and to RedHardSupra who have both helped in my tuning adventures with great knowledge and insight. There is a little additional info to be added to this post for others doing this and I will add later.
Robert
08-14-2006, 11:01 PM
#19
TECH Addict
iTrader: (21)
Join Date: Nov 2005
Location: Maine USA
Posts: 2,209
Likes: 0
Received 0 Likes
on
0 Posts
Great read, thanks Robert for bringing it up.
I'll be in the same boat soon instead of the one I am on now if ya know what I mean
(only EFI instead of HPT).
Cheers
Beer
I'll be in the same boat soon instead of the one I am on now if ya know what I mean
(only EFI instead of HPT).Cheers
Beer
08-14-2006, 11:06 PM
#20
TECH Enthusiast
iTrader: (14)
Join Date: Apr 2005
Location: NE Ohio
Posts: 591
Likes: 0
Received 0 Likes
on
0 Posts
Glad you got things worked out Robert.
To answer your question regarding the idle cells, you can either tune them by hand or change the filter in the custom histogram that you created. The original filter excluded idle, decel and WOT cells (PID.6310>0 and PID.6310<17)
To capture idle only cells (stay in SD with MAF disabled)
1) Delete this filter (save), start your car and let it idle.
2) Once it gets into Closed loop (2-5 minutes or so) start your logger.
3) Log for a few minutes, adjust your VE
4) Reset your fuel trims and log again.
5) Once VE is correct, use the custom histogram to adjust the affected MAF cells.
***As we discussed, idle may end up a tad rich (even with VE modified) due to differences in injector pulse width of the old and new injectors. If this is the case, you'll need to make some adjustments to your fueling tables......or just live with it
To answer your question regarding the idle cells, you can either tune them by hand or change the filter in the custom histogram that you created. The original filter excluded idle, decel and WOT cells (PID.6310>0 and PID.6310<17)
To capture idle only cells (stay in SD with MAF disabled)
1) Delete this filter (save), start your car and let it idle.
2) Once it gets into Closed loop (2-5 minutes or so) start your logger.
3) Log for a few minutes, adjust your VE
4) Reset your fuel trims and log again.
5) Once VE is correct, use the custom histogram to adjust the affected MAF cells.
***As we discussed, idle may end up a tad rich (even with VE modified) due to differences in injector pulse width of the old and new injectors. If this is the case, you'll need to make some adjustments to your fueling tables......or just live with it