-LTFT after sc
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
I never done any injector calibration before but with stock tune the value was 4.19 to 4.59.
is this right?
as I know is that the stock injector is around 32 and the kit is 60.
for me it should be 90%
Burning Brakes
Joined: Jan 2006
Posts: 1,130
Likes: 33
the tuner done it, the value is 6.56 in high kpa and 6.96 in low kpa
I never done any injector calibration before but with stock tune the value was 4.19 to 4.59.
is this right?
as I know is that the stock injector is around 32 and the kit is 60.
for me it should be 90%
I never done any injector calibration before but with stock tune the value was 4.19 to 4.59.
is this right?
as I know is that the stock injector is around 32 and the kit is 60.
for me it should be 90%
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
the tuner done it, the value is 6.56 in high kpa and 6.96 in low kpa
I never done any injector calibration before but with stock tune the value was 4.19 to 4.59.
is this right?
as I know is that the stock injector is around 32 and the kit is 60.
for me it should be 90%
I never done any injector calibration before but with stock tune the value was 4.19 to 4.59.
is this right?
as I know is that the stock injector is around 32 and the kit is 60.
for me it should be 90%
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
You can't get the 60#/hr injectors "right" because the table maxes out too early. Those values are reasonable (assuming you're talking g/sec) but my IFR table goes from 7.31 @ 0 kPa to 8.00 @ 80 kPa (of manifold vacuum). Upping your IFR would shorten the pulsewidth and bring your LTFTs closer to 0.
my table start with 6.56@252 gm/sec@map kpa, and end's with 6.96@18.
I will change it to 7.56@252 & 8@18.
and see what will happen.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
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Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
Probably not. I have no idea how your car was tuned or what a scan looks like now. You need to be tuning with a wide band.
If you raise the IFR it will bring your fuel trims in line but it will also lean out WOT fueling. To get it to where you're achieving the commanded PE and fuel trims are ~0 you need to:
- Get your injector data as correct as possible (at least the size for WOT purposes)
- Tune your MAF or VE tables
The above is like a 30,000 foot view. More like a view from the space station.
If you raise the IFR it will bring your fuel trims in line but it will also lean out WOT fueling. To get it to where you're achieving the commanded PE and fuel trims are ~0 you need to:
- Get your injector data as correct as possible (at least the size for WOT purposes)
- Tune your MAF or VE tables
The above is like a 30,000 foot view. More like a view from the space station.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
I did add 1 to IFR table, after testing the LTFT is totaly unstable.
0 on low MAP and -16 on 100 MAP.
I think I will try to do the MAF, I didn't wont to do it but this is life.
se la ve.
I only wanted to know if it's normal to tune the MAF after installing the sc.
thanks
0 on low MAP and -16 on 100 MAP.
I think I will try to do the MAF, I didn't wont to do it but this is life.
se la ve.
I only wanted to know if it's normal to tune the MAF after installing the sc.
thanks
Melting Slicks
Joined: May 2008
Posts: 2,121
Likes: 2
From: CT
I did add 1 to IFR table, after testing the LTFT is totaly unstable.
0 on low MAP and -16 on 100 MAP.
I think I will try to do the MAF, I didn't wont to do it but this is life.
se la ve.
I only wanted to know if it's normal to tune the MAF after installing the sc.
thanks
0 on low MAP and -16 on 100 MAP.
I think I will try to do the MAF, I didn't wont to do it but this is life.
se la ve.
I only wanted to know if it's normal to tune the MAF after installing the sc.
thanks
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
You're making some very wrong assumptions and it's clear you don't really know what you're doing with regard to tuning. You need to have an understanding of what the tables do, how LTFTs work.....etc. etc. And you need to be tuning with a wide band and understand how that works.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
You're making some very wrong assumptions and it's clear you don't really know what you're doing with regard to tuning. You need to have an understanding of what the tables do, how LTFTs work.....etc. etc. And you need to be tuning with a wide band and understand how that works.
I done tuning for NA cars for so long time since LT1(limited number of my own cars and some frinds), never done SC or injector replacement, I admit to that.
but LTFT is used as I know for normal driving, so it's not that important to do it.as it's corrected by the ECU for nunWOT driving.
I was (and still) intersted to correct it so my PE table will be as I planned, and not use wideband for every mod in the PE.
as for the problem of the BAP, it's confirmed as the fuel pressure drops after 3-4psi boost. as for the PE table it's commanded to 11.3AFR where actual AFR was 19.
it was a wideband.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
You're making some very wrong assumptions and it's clear you don't really know what you're doing with regard to tuning. You need to have an understanding of what the tables do, how LTFTs work.....etc. etc. And you need to be tuning with a wide band and understand how that works.
Judging from his questions, I think this is the wrong situation to learn FI tuning in. Learn by watching this done by a professional or it will be an expensive learning curve. N/A tuning is nothing like FI tuning. If he is asking LTFT questions with IFR and MAF tuning, its clear he didnt master N/A tuning and shouldnt be saying he did. Part throttle LTFT's are the first thing done in any tune.
Last edited by SpinMonster; Sep 8, 2009 at 01:56 AM.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
thanks 5LiterEater,
I done tuning for NA cars for so long time since LT1(limited number of my own cars and some frinds), never done SC or injector replacement, I admit to that.
but LTFT is used as I know for normal driving, so it's not that important to do it.as it's corrected by the ECU for nunWOT driving.
I was (and still) intersted to correct it so my PE table will be as I planned, and not use wideband for every mod in the PE.
as for the problem of the BAP, it's confirmed as the fuel pressure drops after 3-4psi boost. as for the PE table it's commanded to 11.3AFR where actual AFR was 19.
it was a wideband.
I done tuning for NA cars for so long time since LT1(limited number of my own cars and some frinds), never done SC or injector replacement, I admit to that.
but LTFT is used as I know for normal driving, so it's not that important to do it.as it's corrected by the ECU for nunWOT driving.
I was (and still) intersted to correct it so my PE table will be as I planned, and not use wideband for every mod in the PE.
as for the problem of the BAP, it's confirmed as the fuel pressure drops after 3-4psi boost. as for the PE table it's commanded to 11.3AFR where actual AFR was 19.
it was a wideband.
Your LTFT's will have a range and just because they go down to -18 doesnt tell what it goes up to on the high end. Varying cruise speeds and loads have to be sampled to keep the average from triggering rich or lean CELs at stoic. If the -18 is only at idle scan for the MAF freq at idle and lower only those cells (raises the LTFT to lean out) to narrow the average on the MAF table. This wont change fueling at other rpms and force a retune with a wideband.
Once you change IFR and PE, the car needs to be retuned with a wideband under load to verify fuel curves. Put the calculator away. It wont get it right.
Last edited by SpinMonster; Sep 8, 2009 at 02:07 AM.
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
If you're using a BAP and 60lb motron injectors then the commanded a/f calculations for PE are all out the window since the BAP varies voltage making you have to artificially increase the PE table even as high as 60% over at high rpm. The injectors max out the biggest input value which also throws off the calculation.
I am not a pro in tuning, but from what I know is that WOT is openloop and not closedloop operation, for me that means when entring WOT the ECU reads the air entered, load, IFR, injecter... and PE table, with no feedback to correct fueling.
the effect of BAP, is to pump enugh fuel in the fuel rail to maintain the pressure as the injectors starts consuming in high rate and full cycle, based on the commanded value in PE.
so is this right?
Thread Starter
Instructor
Joined: Sep 2007
Posts: 174
Likes: 17
From: Dubai Dubai
Judging from his questions, I think this is the wrong situation to learn FI tuning in. Learn by watching this done by a professional or it will be an expensive learning curve. N/A tuning is nothing like FI tuning. If he is asking LTFT questions with IFR and MAF tuning, its clear he didnt master N/A tuning and shouldnt be saying he did. Part throttle LTFT's are the first thing done in any tune.no one starts a pro, bro.