Adding fuel
Thread Starter
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Adding fuel
Ok forgive me if this is a dumb question but again I am just learning. To tune the A/F mixture is the injector constant how to make global changes across the board then use the WOT A/F tables to getthe proper A/F under WOT? I am messing around with the VE tables at the moment (Using VE master) to try and get the BLM's to 128 across the board (prety close now but it could be better) I am just trying to figure out as much as posible and m having a hard time finding information that is to the point. I had a link that was great and explained basic tuning including fuel A/F and timing but I lost it.
Heel & Toe
Joined: Feb 2000
Posts: 22
Likes: 0
From: Lemoore, Australia
Unless you have changed the injector size and/or cubic inch you should not be changing the injector constant as it is used by almost every calculation the computer does....AE, DE, EGR etc. Do your VE tables, THEN do your PE tables, THEN your AE, etc
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by FD2BLK
Ok forgive me if this is a dumb question but again I am just learning. To tune the A/F mixture is the injector constant how to make global changes across the board then use the WOT A/F tables to getthe proper A/F under WOT? I am messing around with the VE tables at the moment (Using VE master) to try and get the BLM's to 128 across the board (prety close now but it could be better) I am just trying to figure out as much as posible and m having a hard time finding information that is to the point. I had a link that was great and explained basic tuning including fuel A/F and timing but I lost it.
Just remember that you CAN'T change the target AFR that the PCM will attempt to control at. In closed loop the PCM always targets 14.7 but you can control the constants that fuel the engine that the PCM uses to arrive at 14.7 AFR. And you can control open loop AFR as well as PE AFR. If you change the injector constant you will have to go back and change the PE tables slightly to adjust. Another way to get a global change is to massage the MAF sensor tables. Just make small changes in the areas where its needed.
Thread Starter
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Tom,
I was hoping you would chime in and you confirmed almost exactly what I was thinking. I am using the VE tables right not trying to get 128 BLMs across the board, will follow yours and Moats advice and shoot for 125 now. I am using VE Master and having some success but I have made 2 30 min runs at varing loads and RPMs but the BLMs still tend to want to stay around 134-137. I do see that the last time I changed the tunes ve table with vemaster that it had some success in several RPM/load ranges and it seems to be comming around. I have been looking at the MAF tables and was thinking they may need a little tweek but am hesitant to mess with them at the moment.
I was hoping you would chime in and you confirmed almost exactly what I was thinking. I am using the VE tables right not trying to get 128 BLMs across the board, will follow yours and Moats advice and shoot for 125 now. I am using VE Master and having some success but I have made 2 30 min runs at varing loads and RPMs but the BLMs still tend to want to stay around 134-137. I do see that the last time I changed the tunes ve table with vemaster that it had some success in several RPM/load ranges and it seems to be comming around. I have been looking at the MAF tables and was thinking they may need a little tweek but am hesitant to mess with them at the moment.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by FD2BLK
Tom,
I was hoping you would chime in and you confirmed almost exactly what I was thinking. I am using the VE tables right not trying to get 128 BLMs across the board, will follow yours and Moats advice and shoot for 125 now. I am using VE Master and having some success but I have made 2 30 min runs at varing loads and RPMs but the BLMs still tend to want to stay around 134-137. I do see that the last time I changed the tunes ve table with vemaster that it had some success in several RPM/load ranges and it seems to be comming around. I have been looking at the MAF tables and was thinking they may need a little tweek but am hesitant to mess with them at the moment.
I was hoping you would chime in and you confirmed almost exactly what I was thinking. I am using the VE tables right not trying to get 128 BLMs across the board, will follow yours and Moats advice and shoot for 125 now. I am using VE Master and having some success but I have made 2 30 min runs at varing loads and RPMs but the BLMs still tend to want to stay around 134-137. I do see that the last time I changed the tunes ve table with vemaster that it had some success in several RPM/load ranges and it seems to be comming around. I have been looking at the MAF tables and was thinking they may need a little tweek but am hesitant to mess with them at the moment.
Hmm your trims are fairly high. Are the O2 sensors in good shape? The reason I ask is because them boys are the final control element. If they are lazy, they could cause the PCM to command a higher than normal trim number even if the AFR is correct. If everything is OK and the trims are true, you could easily mod the MAF tables to correct this. Using your scan data look at the MAF flow numbers where the engine is running. Knowing what the flow is, will tell you about where to modify the MAF tables. Make small changes, no more than a 5% change will make a significant change. What RPMs are the trims hovering in the 130s at? And what is the MAF flow rate at these points?
Burning Brakes
Joined: Apr 2001
Posts: 1,209
Likes: 0
From: Toronto Ontario
St. Jude Donor '13
MAF Values
Hi Tom,
Just want to clearify, bare with me.. In this scenario you would increase the MAF values by 5% in the desired areas? This will have the effecto of adding fuel in these areas?
Therefore, log the MAF activity and note the MAF frequencies where more fuel could be used and then increase the grams/second by a few percent? Sounds redundant of me, but I just want to make sure I understand correctly.
Thanks,
Victor
Just want to clearify, bare with me.. In this scenario you would increase the MAF values by 5% in the desired areas? This will have the effecto of adding fuel in these areas?
Therefore, log the MAF activity and note the MAF frequencies where more fuel could be used and then increase the grams/second by a few percent? Sounds redundant of me, but I just want to make sure I understand correctly.
Thanks,
Victor
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Thread Starter
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Originally Posted by 89'Bowtie
Hi Tom,
Just want to clearify, bare with me.. In this scenario you would increase the MAF values by 5% in the desired areas? This will have the effecto of adding fuel in these areas?
Therefore, log the MAF activity and note the MAF frequencies where more fuel could be used and then increase the grams/second by a few percent? Sounds redundant of me, but I just want to make sure I understand correctly.
Thanks,
Victor
Just want to clearify, bare with me.. In this scenario you would increase the MAF values by 5% in the desired areas? This will have the effecto of adding fuel in these areas?
Therefore, log the MAF activity and note the MAF frequencies where more fuel could be used and then increase the grams/second by a few percent? Sounds redundant of me, but I just want to make sure I understand correctly.
Thanks,
Victor
Last edited by FD2BLK; Jun 28, 2005 at 12:53 AM.
