Looking for Knowledgeable MAF Tuners

[84Elky]

Am working on expanding the Speed Density Log File Analyzer to handle MAF engines. Would like to have some proficient MAF tuners (eg - $32-BUA, $32B, $6E, $0D) who would be willing to review the Beta MAF Analyzer and offer constructive criticism and recommend enhancements. The Analyzer reads a log file, organizes it and produces information in a format allowing rapid tuning.

If interested, please click on my User Name and send me an email. In a few days, I'll send you a Beta Analyzer via return email for your review.


Before that, a couple of questions (I'm SD proficient, but less MAF):
1.
As I look at the various ADX files, none report TPS%. They only report TPS volts. Looking at a log, how does one determine a WOT state without knowing TPS%?

2.
$32-BUA, $32B and $6e MAF Tables are Volts .vs Air Flow (gm/sec). But the ADX files for these masks only report Air Flow and do not appear to report MAF volts. Lacking that, how do you know what to change to affect BLM or WBo2 AFR?

Looking forward to your replies.

Elky

[Stokes1114]

I'm interested in checking this out. I run $OD maf on my 93 truck and would love to get this to work with my 02 Sierra 0411. PM sent

[steveo]

1. some datastreams dont contain tps% but lots do. i assume by WOT you're trying to determine if an engine is in power enrichment. tps% is the completely wrong way to determine if an engine is in power enrichment, and can only be used to tell if the throttle is physically wide open. lots of calibrations wont go into power enrichment at 100% throttle until a delay time has passed. most datastreams contain a bit to tell you if you're in power enrichment or not, i'd recommend using that. if it lacks a bit for power enrichment i bet it would clear the closed loop bit while in power enrichment so you could probably use that

2. you pretty much ignore the voltage axis of the table. you find the closest airflow cell and adjust that one while smoothing adjacent cells. i know its kind of weird to tune but it does actually make sense once you're doing it. i'll give you an example. lets say you have a really simple maf that's volts/AFGS and you have a table like this:

volts,afgs
1,22
2,34
3,56

now lets say you have a log entry for 25 afgs and the desired correction is +10%

you find the table values around 25 afgs. in this case, 1 volts is the closest, but you need to give 2 volts a bit of a bump too so the curve is maintained. i'd adjust roughly as follows, allowing the magnitude of adjustment to be affected by how close the AFGS value is:

volts,afgs
1,22 * 1.10
2,34 * 1.03
3,56

what you're effectively doing in other words, is instead of saying 'at 1 volt there is 10% more airflow', since you don't have enough data to do that, is saying 'hey, where you think there's 22 afgs of airflow, there's actually 24.2 afgs'.

i hope that makes sense, this logic is the same for mafs that are frequency tables (hz/afgs rather than volts/afgs)

you should look at how my trimalyzer tool some time, i tried to write a tool that works almost automatically on practically any CSV log file without knowing anything about the particular ECM. it does suck a bit with MAF tuning though, i just kind of hacked it in there. maybe it'll give you some ideas to improve your tool

[steveo]

one more thing, if you learn to use cubic splines that really helps when trying to automate modifying a 2d table while maintaining aspects of its existing shape and curvature, and also very helpful for playing with any table when your input points don't necessarily align with existing cells. definitely worth looking into for an automatic maf tuning tool if you want to get deep into it

[84Elky]

1. some datastreams dont contain tps% but lots do. i assume by WOT you're trying to determine if an engine is in power enrichment. tps% is the completely wrong way to determine if an engine is in power enrichment, and can only be used to tell if the throttle is physically wide open. lots of calibrations wont go into power enrichment at 100% throttle until a delay time has passed. most datastreams contain a bit to tell you if you're in power enrichment or not, i'd recommend using that. if it lacks a bit for power enrichment i bet it would clear the closed loop bit while in power enrichment so you could probably use that

steveo --- Tks for the detailed reply.
Regarding WOT -- Was not referring to PE, but truly determining WOT without TPS%. As you know, PE can be invoked at much less than 100% TPS (WOT). With TPS% reproted, it's easy to determine a WOT state. But with only voltage, how? I ask because all masks use various routines to determine TPS% from voltage, starting with a base-point assumption of voltage at 0%. For example. SD $8d uses 0.62v =0%TPS, from which TPS% is calculated based on voltage above that. Said another way, there is not a linear relationship between TPS sensor voltage and %. Lacking TPS%, I'm stuck on how to determine WOT unless there is a given voltage above which WOT can be assumed. But then it's only an assumption.

Regarding the masks that report TPS% and other matters, I will send a PM to discuss.

2. you pretty much ignore the voltage axis of the table. you find the closest airflow cell and adjust that one while smoothing adjacent cells. i know its kind of weird to tune but it does actually make sense once you're doing it. i'll give you an example. lets say you have a really simple maf that's volts/AFGS and you have a table like this:

Understand your example. So would 3D tables be helpful?
---BLM at RPM .vs. Air Flow
---BLM at RPM .vs. LV8 load
---BLM at RPM .vs. Hz frequency
The variation of BLM in each cell from 128 indicates the approximate correction factor needed to obtain 128 BLM.
This is what I do for SD to adjust the VE tables.

[steveo]

i cant imagine how rpm would be very helpful in maf tuning

also can’t really imagine how 100% tps would be useful in fuel tuning as you want to tune power enrichment across the board, but if you must, you would have to say wot if volts > x and make the user input x. or get tricky and make your users floor it at least once in your log, then find the greatest tps voltage, using it as 100% tps

[84Elky]

i cant imagine how rpm would be very helpful in maf tuning

Aren't Air Flow and LV8 load, which in part determine BLM and AFR, directly related to RPM? If not RPM, then what type of MAF table would be of benefit? For many of the early masks datastrams, voltage is not reported. Only in later masks datastreams is Hz reported which would allow AirFlow or LV8 to be correlated with it. Thoughts appreciated.[/OUOTE]

also can’t really imagine how 100% tps would be useful in fuel tuning as you want to tune power enrichment across the board, but if you must, you would have to say wot if volts > x and make the user input x. or get tricky and make your users floor it at least once in your log, then find the greatest tps voltage, using it as 100% tps

You're right. I confused MAF with WOT. In analyzing and reporting WOT AFR when a WBo2 sensor is used, msut have a way to determine WOT. Your solution is the only one I've thought of. Not elegant, but doable to have a voltage threshold entered.[QUOTE]