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Apparently the input (pin for the A/C pressure sensor is commonly used. I've suggested the pin the Corvette PCM uses for oil temperature because some scanners show a reading for oil temp on the F-Body (-40° for an open circuit). I imagine you would have to change the scalar in the program, or use an external spreadsheet to convert.
Location: Born on the Florida West Coast, now where can I retire?
Posts: 1,505
Re: How do you data log wideband?
Pin D27 is normally unused and unwired and that is why it can be wired for any function. The problem is that none of the usual scanners use it. Maybe try my scan9495? It has that option to use it instead of the Baro input. You are on your own to scale it though. Results will be in the Baro line and will be labeled D27.... It inputs as an 8 bit number from 0 to 255 and is displayed as a voltage from 0 to 5vdc. The formula used to convert to baro is (8 bit number reading) + 28.06) times 0.369). Dividing the displayed reading by that gets you back to the original 0-255. Then use your formula to get your sensor value. If you can do a scan, I may be able to help with the math ;-) First time for me. Like Fred said you would have to use something like an Excel spreadsheet to manage this. The users asking me for this option could do that themselves.
Pin D27 is normally unused and unwired and that is why it can be wired for any function. The problem is that none of the usual scanners use it. Maybe try my scan9495? It has that option to use it instead of the Baro input. You are on your own to scale it though. Results will be in the Baro column. It inputs as an 8 bit number from 0 to 255. The formula used to convert to baro is (8 bit number reading) + 28.06) times 0.369). Dividing the displayed reading by that gets you back to the original 0-255. Then use your formula to get your sensor value. If you can do a scan, I may be able to help with the math ;-) First time for me. Like Fred said you would have to use something like an Excel spreadsheet to manage this. The users asking me for this option could do that themselves.
Very easy to use - thank you. I changed it to pin 27 but it's showing like 101v or something and doesn't fluctuate from that.
Location: Born on the Florida West Coast, now where can I retire?
Posts: 1,505
Re: How do you data log wideband?
Originally Posted by raroz28
Very easy to use - thank you. I changed it to pin 27 but it's showing like 101v or something and doesn't fluctuate from that.
That sounds like you did not change the setting. The baro reading is usually around 100 and does not change during a scan because it is set at engine start time and remains fixed. If the setting is changed, the label should change from "Baro pressure-kpa" to "D27 input (0-5v)".
If it does not change, the setting was not changed. Make sure to click on Exit on the Setup screen. This image shows what it looks like when changed and there is nothing attached to pin D27...5v. I was wrong about having to do the calculations, that is done by the program and the result is a reading from 0 to 5vdc.
That sounds like you did not change the setting. The baro reading is usually around 100 and does not change during a scan because it is set at engine start time and remains fixed. If the setting is changed, the label should change from "Baro pressure-kpa" to "D27 input (0-5v)".
If it does not change, the setting was not changed. Make sure to click on Exit on the Setup screen. This image shows what it looks like when changed and there is nothing attached to pin D27...5v. I was wrong about having to do the calculations, that is done by the program and the result is a reading from 0 to 5vdc.
ok, got it. Not sure if its a glitch, but i did check the box each time but i found that if you check it prior to connecting to the vehicle and starting the scan, it will be unchecked after you start the scan. Once i started the scan and went into settings, i was able to check the box and got the result you shared. Here is what i was seeing before:
So I got this logging and the software is great. I added in a formula based on my 10:1-17:1 afr gauge. Its a 4v autometer. You can see, I've moved the D27 output next to the RPM to read it easier. I used ((7/4)*voltage)+10 to calculate my AFR. The log is below and I'm wondering if my issue is at low RPM. I know that I'm running rich, but I think I have squared a lot of that away and it's running much better by adjusting the fuel tables from 2800 RPM and up, but when I look at RPM below that, it looks like it's super lean. What's happening is after a WOT, it will have to burn off excess fuel but once i burn it up and build RPM, it takes off.
Data log:
And here is the fuel tables. Should I add some fuel at lower RPM? This is the PE AFR Correction - RPM table in tunerpro RT.
Location: Born on the Florida West Coast, now where can I retire?
Posts: 1,505
Re: How do you data log wideband?
You are probably asking questions about things we have no experience with. I'm just a computer geek and we (Fred and I) have never done any programing..... good luck.
You are probably asking questions about things we have no experience with. I'm just a computer geek and we (Fred and I) have never done any programing..... good luck.
Well thank you so much - the software is great. Super easy to use and with it I can finally pull logs and see what my car is doing. Thank you for the recommendation, I didn't see your software in all my searches, mainly just eehack which i could never get to make sense. Yours works perfectly. Thank you again.
Is the data in the chart of RPM vs. pin D27 wideband readings an extract from a continuous log? Or is that an assembled set of data from various points in the log? If you have eased up on the accel petal in a continuous log, it's going to go lean because under certain circumstances the PCM cuts the fuel off on decel. If the throttle is opening, the mixture may be enriched. I think what you really need is a complete runup from idle, go WOT, and track the entire pull. Then you will see where things are not where they are supposed to be.
If you have the original log in .csv format, attach it to a post so I can download it if you want. While I'm not a tuner, the guy who bought my Formula is, and he works with a wideband to sort things out.
Is the data in the chart of RPM vs. pin D27 wideband readings an extract from a continuous log? Or is that an assembled set of data from various points in the log? If you have eased up on the accel petal in a continuous log, it's going to go lean because under certain circumstances the PCM cuts the fuel off on decel. If the throttle is opening, the mixture may be enriched. I think what you really need is a complete runup from idle, go WOT, and track the entire pull. Then you will see where things are not where they are supposed to be.
If you have the original log in .csv format, attach it to a post so I can download it if you want. While I'm not a tuner, the guy who bought my Formula is, and he works with a wideband to sort things out.
Hey Fred, that snippet is from a WOT pull. I have dialed back the fuel a little more. On this sheet, if you search for the max rpm values, you can see the rampup. For example, for the high value 6923 RPM, all the values prior to that are at WOT. I am wondering if my stumble at lower RPM is actually a result of being lean, and not from excess fuel burning off.
The log file is here. https://docs.google.com/spreadsheets...it?usp=sharing
Here is an example of a WOT pull. I have added in the AFR and Lambda tables. Per Moe, I should be looking for .78 lambda at WOT.
It would be useful to see the full log, e.g. when it transitions to PE mode. What A/F ratio are you targeting in PE? How much boost are you running? I'm no tuner, but if it was nitrous I’d have a better understanding of desired A/F ratio. Haven’t done anything w/ forced induction.
Given the extent of the mods it would seem like a dyno tune would be advantageous. I watched them do it on my setup and it took a lot of pulls even for a shop that specialized in big nitrous setups. Same guys that built and tuned George Baxter's 1,125 flywheel HP Vortech S/C record holding LT1 “back in the day”.
And again, I'm just offering to take a look at the log so I can try and understand your numbers. Not sure if I can help much.
It would be useful to see the full log, e.g. when it transitions to PE mode. What A/F ratio are you targeting in PE? How much boost are you running? I'm no tuner, but if it was nitrous I’d have a better understanding of desired A/F ratio. Haven’t done anything w/ forced induction.
Given the extent of the mods it would seem like a dyno tune would be advantageous. I watched them do it on my setup and it took a lot of pulls even for a shop that specialized in big nitrous setups. Same guys that built and tuned George Baxter's 1,125 flywheel HP Vortech S/C record holding LT1 “back in the day”.
And again, I'm just offering to take a look at the log so I can try and understand your numbers. Not sure if I can help much.
The google sheet i put above is the only log output i have. Per Moe, it should be .78 lambda, or about 11.8 afr.
May as well keep the thread updated for future searches:
I've been pulling back fuel and am seeing great results. The car has 18x11" Nitto NT05 and it has a really really hard time getting any traction at lower RPM, but I think a big part of that is the 4.10 gear that I need to swap out.
My fuel tables are now scaled back to here:
I have been doing my pulls from a slow roll and going to WOT at about 2500-3000 RPM. The scatter plot below shows that I'm in a much better place than I was before. The desire for the engine to stall is gone now after WOT pulls, however, a slight flutter remains after the pull to burn off excess fuel, so it is still a tad bit rich. Once it is burned off, it drives fine until I do the next WOT pulls.
My only concern is that now for the first time in the ramp up i am seeing 13-12 afr, whereas before i was in low 11's and high 10's. I do not want to scale back anymore fuel because I am concerned that my issue with the excess fuel after WOT could be related to something else and not flooding at WOT, however the line trends toward the desired AFR (11.8) and eventually settles there around peak RPM, so I'm thinking I could potentially pull some fuel.
I'll keep driving and analyzing and see how it turns out.
04-20-2023, 07:00 PM
