FIC 750's scaling and latency issues and THE MEGA FIC 750 thread (hopefully)
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FIC 750's scaling and latency issues and THE MEGA FIC 750 thread (hopefully)
This is bizzare, but these injectors are acting absolutely weird....
Based on some values I found here on evom
I scaled them to 713 and set latencies as follows (al\lupo values):
3.312
2.04
1.296
0.912
0.792
0.6
0.336
STFT and MTFT were -4.9978 and -0.291399999999999 when idling for about 15 mins
Go out and do a cruise log: STFT and MTFT were -4.9978 and -0.8797
I am excited that I have got them down good. Car idles great, no throttle hang etc...but, read on...
So, I come back home and shut car down. A little while later, I start it up, let her warm up and for shizzles and grins, I decided to log again...
STFT and MTFT were -4.9978 and -6.1744
What gives? How does it suddenly change? Not sure what could have happened here...
Dumb question - How does one come up with these latency values? Is it just bumping values up and down or is there a formula to calculate it...
Here is the end-all part I was referring to, I am hoping this thread helps to address all FIC 750 scaling and latencies.....If people are so kind enough to post their values, I will keep adding to this thread...
1) roadspike
Scaled to 696
3.312
2.04
1.296
0.912
0.792
0.6
0.336
2) kreonic
scaled to 650
3.312
1.68
1.032
0.84
0.552
0.456
0.36
3) evoredy
scaled to 665
3.312
1.68
1.2
0.792
0.72
0.456
0.36
4) al\lupo
scaled to 696
also, with 713 scaling he got -0.39% (low) and +0.195% (mid).
3.312
2.04
1.296
0.912
0.792
0.6
0.336
5) John Bradley
Scaling 650
3.312
1.68
1.032
0.84
0.552
0.456
0.36
Based on some values I found here on evom
I scaled them to 713 and set latencies as follows (al\lupo values):
3.312
2.04
1.296
0.912
0.792
0.6
0.336
STFT and MTFT were -4.9978 and -0.291399999999999 when idling for about 15 mins
Go out and do a cruise log: STFT and MTFT were -4.9978 and -0.8797
I am excited that I have got them down good. Car idles great, no throttle hang etc...but, read on...
So, I come back home and shut car down. A little while later, I start it up, let her warm up and for shizzles and grins, I decided to log again...
STFT and MTFT were -4.9978 and -6.1744
What gives? How does it suddenly change? Not sure what could have happened here...
Dumb question - How does one come up with these latency values? Is it just bumping values up and down or is there a formula to calculate it...
Here is the end-all part I was referring to, I am hoping this thread helps to address all FIC 750 scaling and latencies.....If people are so kind enough to post their values, I will keep adding to this thread...
1) roadspike
Scaled to 696
3.312
2.04
1.296
0.912
0.792
0.6
0.336
2) kreonic
scaled to 650
3.312
1.68
1.032
0.84
0.552
0.456
0.36
3) evoredy
scaled to 665
3.312
1.68
1.2
0.792
0.72
0.456
0.36
4) al\lupo
scaled to 696
also, with 713 scaling he got -0.39% (low) and +0.195% (mid).
3.312
2.04
1.296
0.912
0.792
0.6
0.336
5) John Bradley
Scaling 650
3.312
1.68
1.032
0.84
0.552
0.456
0.36
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First you need to drive the car for a significant period of time to really dial in the fuel trims.
Second and more importantly what are you using to log trims? I see you quotoing STFT and MTFT. These are erroneous values used in many OBD2 loggers. You need to look at your Low, Mid, and High trims in evoscan or mitsulogger.
Lastly, your trims can and will be constantly changing. This is what their job is, to change so that you keep a stoichiometric AFR. Trims drift when the engine is warming up, coasting down big hills, recovering from a warm start, etc... Just find a happy medium.
Second and more importantly what are you using to log trims? I see you quotoing STFT and MTFT. These are erroneous values used in many OBD2 loggers. You need to look at your Low, Mid, and High trims in evoscan or mitsulogger.
Lastly, your trims can and will be constantly changing. This is what their job is, to change so that you keep a stoichiometric AFR. Trims drift when the engine is warming up, coasting down big hills, recovering from a warm start, etc... Just find a happy medium.
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First you need to drive the car for a significant period of time to really dial in the fuel trims.
Second and more importantly what are you using to log trims? I see you quotoing STFT and MTFT. These are erroneous values used in many OBD2 loggers. You need to look at your Low, Mid, and High trims in evoscan or mitsulogger.
Lastly, your trims can and will be constantly changing. This is what their job is, to change so that you keep a stoichiometric AFR. Trims drift when the engine is warming up, coasting down big hills, recovering from a warm start, etc... Just find a happy medium.
Second and more importantly what are you using to log trims? I see you quotoing STFT and MTFT. These are erroneous values used in many OBD2 loggers. You need to look at your Low, Mid, and High trims in evoscan or mitsulogger.
Lastly, your trims can and will be constantly changing. This is what their job is, to change so that you keep a stoichiometric AFR. Trims drift when the engine is warming up, coasting down big hills, recovering from a warm start, etc... Just find a happy medium.
I am quoting low and mid in Evoscan...I could swear thats what they say next to those values. My high always stays at .1008.
Thanks, I am learning all this stuff, so I appreciate the tips
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SFTF is typically means the short term fuel trim. MTFT typically means main fuel trim.
So, to avoid confusion. What are your Low, Mid, and High values from evoscan.
The short fuel trim in evoscan is the *right now* correction. If it says consistently lean or rich the ecu will change the low, mid, or high trim to reflect the discrepancy. Low trim is for low load situations such as idle, mid is typically for slow speed driving, high is usually updated when cruising on the highway.
All trims change with the weather, type of gas, humidity index etc... They will never be perfect. If you are consistently withing + and - 5% you are very good. I usually only make changes when I'm consistently + or - 10% off or more.
So, to avoid confusion. What are your Low, Mid, and High values from evoscan.
The short fuel trim in evoscan is the *right now* correction. If it says consistently lean or rich the ecu will change the low, mid, or high trim to reflect the discrepancy. Low trim is for low load situations such as idle, mid is typically for slow speed driving, high is usually updated when cruising on the highway.
All trims change with the weather, type of gas, humidity index etc... They will never be perfect. If you are consistently withing + and - 5% you are very good. I usually only make changes when I'm consistently + or - 10% off or more.
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SFTF is typically means the short term fuel trim. MTFT typically means main fuel trim.
So, to avoid confusion. What are your Low, Mid, and High values from evoscan.
The short fuel trim in evoscan is the *right now* correction. If it says consistently lean or rich the ecu will change the low, mid, or high trim to reflect the discrepancy. Low trim is for low load situations such as idle, mid is typically for slow speed driving, high is usually updated when cruising on the highway.
All trims change with the weather, type of gas, humidity index etc... They will never be perfect. If you are consistently withing + and - 5% you are very good. I usually only make changes when I'm consistently + or - 10% off or more.
So, to avoid confusion. What are your Low, Mid, and High values from evoscan.
The short fuel trim in evoscan is the *right now* correction. If it says consistently lean or rich the ecu will change the low, mid, or high trim to reflect the discrepancy. Low trim is for low load situations such as idle, mid is typically for slow speed driving, high is usually updated when cruising on the highway.
All trims change with the weather, type of gas, humidity index etc... They will never be perfect. If you are consistently withing + and - 5% you are very good. I usually only make changes when I'm consistently + or - 10% off or more.
Today - I scaled injectors at 731 and will get new latency values.
The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?
So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?
Also, how does the voltage work - why do they have diff values for voltages?
Thanks!
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Thats awesome to know. Thanks for the explaination. From reading, I was led to believe anything below the 5% band range needed correcting...
Today - I scaled injectors at 731 and will get new latency values.
The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?
So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?
Also, how does the voltage work - why do they have diff values for voltages?
Thanks!
Today - I scaled injectors at 731 and will get new latency values.
The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?
So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?
Also, how does the voltage work - why do they have diff values for voltages?
Thanks!
And I think that you're correct with the ms time is the lag time when the injector opens.
My LTFT high never moves also. Does anybodys?
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Thats awesome to know. Thanks for the explaination. From reading, I was led to believe anything below the 5% band range needed correcting...
Today - I scaled injectors at 731 and will get new latency values.
The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?
So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?
Also, how does the voltage work - why do they have diff values for voltages?
Thanks!
Today - I scaled injectors at 731 and will get new latency values.
The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?
So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?
Also, how does the voltage work - why do they have diff values for voltages?
Thanks!
I would subtract 0.1ms to all the numbers in your latency curve and after a couple days I think your low, mid, and high will be very close to 0.
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Okay guys here are my logs from tonight... just got done logging and thought I would post my results so you guys can actually see the results yourself. Low boost is at 16psi and High boost is at 26psi... FYI I didn't even touch the AFR map one single bit! Once again we have to thank John Bradley for updating his FIC 750 scaling... I adjusted a bit and here are the settings I used...
Scaling 650
4.69v- 3.312
7.03v- 1.680
9.38v- 1.032
11.72v- .864
14.06v- .696
16.41v- .552
18.68v- .360
Scaling 650
4.69v- 3.312
7.03v- 1.680
9.38v- 1.032
11.72v- .864
14.06v- .696
16.41v- .552
18.68v- .360
Last edited by Fast_Freddie; Feb 23, 2009 at 01:46 PM.