Thanks hard to keep somethings straight
Thanks hard to keep somethings straight
I found this PDF which I found very helpful in giving a very basic understanding of tuning the GM EFI. So, I figured I'd post it here for anyone who might stumble onto this thread. It answered a lot of my questions and had really good explanation. It's for an older mask so not fully relevant but the explanations of the different functions is very helpful.
https://www.gmcmi.com/wp-content/upl...EFI-System.pdf
It looks like the authors website is no longer around. Which is a shame, it would have been nice to find some more of his write-ups.
It's been pretty busy so I have not had much time to datalog. I got one log in the other day. I adjusted the VE maps based on this and will try and get another log going.
Screen Captures from Data Log 1.xdl
Near Idle BLMs.jpg
Off Idle BLMs.jpg
Spark Advance.jpg
Thanks. So, I get the BLM numbers in the top section and I have the spread sheet to adjust those. But what are the numbers in the green section?Originally Posted by dave w
I'm also curious about the spark advance you've circled. I've seen that while playing back the data log. But I was not sure what was causing that since they are unrealistic numbers. I think that range of RPM vs MAP is where I'm seeing knock so, I don't know if that's what's causing the data to spike like that. I did retard the advance a little in those areas where I saw knock.
I have not messed with the spark advance at all other than turning it down 1-2' in the areas where I saw knock retard.
I was watching my second log file it looks like the spark advance spikes at tip in. Again, I'm not sure if this is just an issue with the data log or something real. But here are screen shots of the dash board right before and during. Dash 0 was a few seconds before (I think I was sitting at a light), Dash 1 is the frame right before and Dash 2 the first frame when it started. The advance spiked for maybe 3-4 frames and then went back down. I don't really see anything out of sorts. Anybody have any thoughts?
I have a '94 GMC with a 6395 $OD stock. So they are not 4l80 specific.
95 model year introduced PWM controlled TCC. run the bin that matches your transmission.
VE, or Volumetric Efficiency, is in simple terms, how much air your engine fills the cylinders in a certain condition, IE load and RPM.
That is Speed Density Fueling. Certain Amount of air requires certain amount of fuel. Systems can self tune to a degree with O2 input, but any time you loose battery power you are back to square 1. And also, they are not that accurate, in this generation of computers, they are made to fine tune, not compensate for large airflow changes. That is why you change VE to tune the lookup table. That is the why. I would highly recommend a Wide band o2, for tuning a cam change. I have a tutorial on how to tune open loop with one in the writeup section.
No need to re-invent the wheel. But we can make it better
I am a green horn regarding tuning, I have to ask admin if this tuning 101 paper would be something helpful to save into the "GM ECM - Bins - TunerPro Definition Files - Wiring Diagrams - Tuner Info!" section? maybe call the folder "basic 101 tuning or heck even call it "start here"
WB is definitely on the shopping list. Just trying to figure out which one to go with. Right now I'm leaning towards the AEM 30-0300 because the price point seems decent. I'm also considering the Innovate LC-2 controller with gauge.
The AEM 30-4110 https://www.aemelectronics.com/produ...uego-afr-gauge is Plug-n-Play if using the WBO2 - Tuning Spreadsheet: http://www.gearhead-efi.com/Fuel-Inj...ng-Spreadsheet
- 0-5v analog output (10-20 AFR range only)
Decided to go with the AEM 30-4110 should hopefully be here this weekend. Whether or not I'll have time to install it is another question.
I am seeing a lot of fluctuations in my BLM readings which is making it really hard to get this down. I did a 30ish mile log yesterday on my commute to work ranging from stop and go traffic to 80mph. Some of the cells saw swings of 12-19 points between the low and high BLM values. So, I'm really curious what the WB will end up showing. I'm also wondering if this could be caused by my NB. I do have a new one sitting on the shelf so maybe I should drop that in and see if it makes a difference.
Edit:
To add to the above, I also wanted to see if may certain things like PE were effecting the results. So, I did an export of the log to Excel and removed all records with PE or Open Loop enabled to see if that would reduce the fluctuations. It changed the averages slightly but still saw large fluctuations in regions with a lot of samples.
Last edited by IamBrad; 07-27-2022 at 06:50 PM.
The WBO2 spreadsheet I posted a link to will filter out PE, AE, and Open Loop data in the cell averages. The WBO2 spreadsheet is for Closed Loop Only tuning.
It's not unusual to have BLM swings. As the BLM / AFR tuning progresses, the BLM / AFR swings will be present but less. It's impossible to ZERO Out the swings.
I've got that thread saved and will be reading through it. Good to know about the BLM swings.The WBO2 spreadsheet I posted a link to will filter out PE, AE, and Open Loop data in the cell averages. The WBO2 spreadsheet is for Closed Loop Only tuning.
It's not unusual to have BLM swings. As the BLM / AFR tuning progresses, the BLM / AFR swings will be present but less. It's impossible to ZERO Out the swings.
Ok, so I was playing around with your spreadsheet and I have some questions. Not so much about the main functionality of the spreadsheet. I think I've figured that out and it's pretty straight forward. The one functionality question I do have is. I see where you have a table for PE Active AFR however, I don't see anywhere that this is used to create an adjustment for the VE map. Is there a different spreadsheet where this is used?
My other question and please keep in mind this is coming from a Excel/Data geek and not a tuner. Is there a reason you are using the Fixed AFR for Closed loop only rather than using the Desired AFR input which would appear to also work with open loop and PE data and allow you to move into the higher RPM ranges as well. Functionality wise it seems like an easy switch since the desired AFR data is already there. Just insert another table populate it with the Desired AFR and compare that to the WBO2 data. I guess if the issue is related to closed loop data you could use this of the Open Loop and PE data.
Anyway, nice work on the spreadsheet.
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