Another Fuel Trim Question.
Another Fuel Trim Question.
Well I've been doing quite abit of reading on fuel trims and adjusting injector latencies lately but was wondering what people with Evoscan should be seeing for there trim numbers. Most of the threads seem to say it should be around zero or you'll see + or - certain %'s but mine are anywhere from 89.0625 for my mid to 100 for my low and 133.5938 for my high. Any thoughts?
100 is the base in EvoScan. Try to reflash your car to set them back to 100. Then, drive for a bit while logging the trims, O2 Feedback and airflow. The O2 feedback is the immediate correction value, so if it gets way off at a certain airflow Hz then thats where you need to adjust.
I've been playing with this stuff and it seems that Low mid and High trims refer to the airflow values ... For example, Low Trim could refer to 19 Hz to 100 Hz and Mid Trim could be 100 Hz to 500 Hz. When I first started messing with these values I thought that low was a short term trim and high was a long term trim but that doesn't seem to be the case.
So, from what I've seen, it seems that you've corrected for your idle airflow (Low Trim) but not your cruising trims.
I've been playing with this stuff and it seems that Low mid and High trims refer to the airflow values ... For example, Low Trim could refer to 19 Hz to 100 Hz and Mid Trim could be 100 Hz to 500 Hz. When I first started messing with these values I thought that low was a short term trim and high was a long term trim but that doesn't seem to be the case.
So, from what I've seen, it seems that you've corrected for your idle airflow (Low Trim) but not your cruising trims.
NIEvo,
EvoScan has the wrong formula and wrong requests for the fuel trims.
I've posted the correct forumlas and requests several times in other fuel trims threads. A quick search should enable you to find what you are looking for.
Eric
EvoScan has the wrong formula and wrong requests for the fuel trims.
I've posted the correct forumlas and requests several times in other fuel trims threads. A quick search should enable you to find what you are looking for.
Eric
. That's where trims hover around 0. And low and hi LTFT's are not dyslexic.
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100 is the base in EvoScan. Try to reflash your car to set them back to 100. Then, drive for a bit while logging the trims, O2 Feedback and airflow. The O2 feedback is the immediate correction value, so if it gets way off at a certain airflow Hz then thats where you need to adjust.
I've been playing with this stuff and it seems that Low mid and High trims refer to the airflow values ... For example, Low Trim could refer to 19 Hz to 100 Hz and Mid Trim could be 100 Hz to 500 Hz. When I first started messing with these values I thought that low was a short term trim and high was a long term trim but that doesn't seem to be the case.
So, from what I've seen, it seems that you've corrected for your idle airflow (Low Trim) but not your cruising trims.
I've been playing with this stuff and it seems that Low mid and High trims refer to the airflow values ... For example, Low Trim could refer to 19 Hz to 100 Hz and Mid Trim could be 100 Hz to 500 Hz. When I first started messing with these values I thought that low was a short term trim and high was a long term trim but that doesn't seem to be the case.
So, from what I've seen, it seems that you've corrected for your idle airflow (Low Trim) but not your cruising trims.
The AirFlow is based on RPM and the throttle body, so it will hold steady of your foot and the terrain are steady. The O2 feedback will bounce a little, but if you graph it you'll see that it's within a fixed range.
I'm currently working on a trial and error basis with the MAF scaling and the trims. It's been proven that lowering the injector scaling will fix the issue, but I feel that the injector scaling has pretty much been nailed down and figured out, while the MAF reading seems to be much more fickle and easily skewed. So, I feel that correcting the MAF scaling is the way to go with stock injectors in the car.
I'm currently working on a trial and error basis with the MAF scaling and the trims. It's been proven that lowering the injector scaling will fix the issue, but I feel that the injector scaling has pretty much been nailed down and figured out, while the MAF reading seems to be much more fickle and easily skewed. So, I feel that correcting the MAF scaling is the way to go with stock injectors in the car.
Well I logged a few runs at the track on Friday and my High or low if they are switched trims are way off during my runs. I was reading 142.96 on my trims. O2 feedback is 100 and airflow is around 1603. What Im wondering is what is this telling me? The car is running great but I would like to learn what all these numbers mean 
NI,
you can let the airflow go, its just a means of seeing how much power you are making, it caps out at 1603 typically.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
*in a minute the tape will self destruct.
you can let the airflow go, its just a means of seeing how much power you are making, it caps out at 1603 typically.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
*in a minute the tape will self destruct.
you can let the airflow go, its just a means of seeing how much power you are making, it caps out at 1603 typically.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
NI,
you can let the airflow go, its just a means of seeing how much power you are making, it caps out at 1603 typically.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
*in a minute the tape will self destruct.
you can let the airflow go, its just a means of seeing how much power you are making, it caps out at 1603 typically.
your actual mid and low (I'm thinking in terms of logworks, but I think we are talking about the same thing) deal in different aspects of your off boost driving or idle.
When you go into wot or over about 35% throttle the car ceases to use the closed loop 14.7 as a target. During this time you should not be seeing any reaction to your low or mid term trims.
During closed loop as the ecu tries to maintain 14.7 it adds or subtracts fuel from what the latencies and injector scaling are allowing. That effort to maintain 14.7 is what you are seeing in the logs. The mid term trim is what the ecu is doing under cruise driving. So while you putter along at 65 and high vacuum or 35, whatever speed, that is when mid term trim is in effect. When you idle for an extended period you might see your short term trim make a move. As I recall evoscan gives you a updated o2 feedback during either mode of driving. The ecu determines how much fuel it needs to remove or add to hit 14.7, that would be the o2 feedback you see.
If it is predominantly negative or positive then that is the way your trims move.
"Your job should you accept it*" is to adjust the injector scaling and or latencies so that the ecu only has to work within a narrow window.
If the latencies or injector scale is off by a lot the trims will affect your fuel maps when the trims go to extremes. Typically a small range of plus or minus 10% is considered OK.
(not sure what number that equates to in evoscan, 110?)
Lastly trying to read the o2 feedback is only worthwhile in determining trends.
The reason you saw 100 (on evoscan) is because that is its base or zero, during your wot driving it shuts off, that is why you see "100".
so the cliff note is: check your mid and low, adjust as necessary. Ignore them if within 10%. The trims are continually updated and at times are at odds with the ecu itself so the zero is a target not a rule.
*in a minute the tape will self destruct.
remember the info is worth what you paid for.
I really don't use evoscan much as it hasn't been updated to log more than one Innovate input. So although the general idea I express is right (I believe) a few of the particulars may be wrong. It likely will continue to indicate trims during wot but as you said the o2 feedback drops off. My feeling is that if the o2 feedback is 100 (zero) then the ecu has stopped updating the trims but is keeping them until you come out of wot.
I think I am correct in saying to you, yes, your 142 means nothing to your wot log, it does indicate (from what I can discern) your latencies may be a little lean. A positive number indicates the ecu is adding fuel in its effort to maintain 14.7.
Perhaps you should dwell on what is labeled mid trim and high trim (although labeled incorrectly) if these numbers approach 150 then they are pegged and you need to adjust your injector scale or latencies. It has been reported that when the numbers are at the extremes they will have an affect on your wot fuel map.
just happened to read your first post and there you start where I just finished.:-)
as far as evoscan trims, you are likely OK. you could download mitsulogger and see if your trims run less than 10. His logger pegs at twelve but I believe he has said within ten percent is OK.
I really don't use evoscan much as it hasn't been updated to log more than one Innovate input. So although the general idea I express is right (I believe) a few of the particulars may be wrong. It likely will continue to indicate trims during wot but as you said the o2 feedback drops off. My feeling is that if the o2 feedback is 100 (zero) then the ecu has stopped updating the trims but is keeping them until you come out of wot.
I think I am correct in saying to you, yes, your 142 means nothing to your wot log, it does indicate (from what I can discern) your latencies may be a little lean. A positive number indicates the ecu is adding fuel in its effort to maintain 14.7.
Perhaps you should dwell on what is labeled mid trim and high trim (although labeled incorrectly) if these numbers approach 150 then they are pegged and you need to adjust your injector scale or latencies. It has been reported that when the numbers are at the extremes they will have an affect on your wot fuel map.
just happened to read your first post and there you start where I just finished.:-)
as far as evoscan trims, you are likely OK. you could download mitsulogger and see if your trims run less than 10. His logger pegs at twelve but I believe he has said within ten percent is OK.
Last edited by nothere; Aug 12, 2007 at 06:01 PM.
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