I have had a persistent stumbling problem and I just compared a video of the data log to a video of the car on track. It looks like every time I mash the throttle too quickly, the AFR goes to 9 or even 8:1 and it stumbles for a bit then clears up and goes like stink. If throttle is applied more slowly, it doesn't stumble. What do I adjust and how? EQ Ratio? Enrichment Ramp in? Enrichment Ramp Out?
Post log and tune
set your eq ratio to what you want it to be and tune it in the best you can.
then you need to analyse the log where you mash the tps and check the afr recorded after this tip in. to adjust it increase the enrichment ramp in (to richen) or decrease the ERI (to lean)
2000 Ford Mustang - Top Sportsman
Here is a log of a run, notice that AFR goes to 8:1 or 9:1 when I hit the gas pedal.18-07-22 12-58-14 (1).hpl What does adjusting the PE Ramp Out do? Mine is set at only .0100 Ramp Out
Last edited by marksawatsky; 07-27-2018 at 08:24 PM.
Ramp in is how fast you reach your requested pe ratio fueling and ramp out is how fast it returns back to stoich from the pe ratio fueling
Thanks. I have read several threads on here that said NA cars usually have their PE Ramp In set from 1.0-1.3 and boosted cars are over 1.5. My boosted car is set at 1.0 but I should try reducing it even more? Would it maintain desired AFR better if my Ramp Out rate was around 1.0 instead of .0100?
you have to minimize the log to exclude the transition zone when tuning wot. this is the most common reason to a funky ramp in value. the second is injector data.
if you can verify that target pe is correct post transition then yes you would have to lower the ramp in to correct the rich tip in issue.
2000 Ford Mustang - Top Sportsman
I start out at 1.0 - if your still rich you could lower the ramp in to adjust accordingly or what I do is log (maf or ve whichever you use) against afr error and against afr commanded and remove fuel from the cells your rich in when you enter pe to bring the fueling inline
Last edited by TCSS07; 07-27-2018 at 09:14 PM.
Easier to see if you actually have a wideband installed since I feel hptuners has a slight delay in logging the transition into pe ... for example in my car afr logging entering pe goes lean for a second on the scanner before shooting down but my wideband goes right to my commanded 11.8
Last edited by TCSS07; 07-27-2018 at 09:15 PM.
Here is a video of the car on track with the data overlayed. The stumble isn't really audible in the video but I can feel it and you can see it in the log when AFR goes to 9:1
https://www.youtube.com/watch?v=5M5TBqUvVR8
either get some dyno time to fine tune the afr or find a nice smooth road/no cops lol - set your pe to a solid number lets say 11.5afr or whatever you want to use and in 3rd gear do a pull from 2500 to redline and get the fueling to read 11.5 during the pull and like i said if your too rich during tip in you'll have to remove fueling from those cells to bring the fueling inline or lower the ramp in but id keep it at 1.0
and for the video you posted that's not really the best way to monitor afr because there are so many throttle lifts and stabs and wheel spins that it'll throw off the fueling - you need to do a nice solid/clean pull and make sure your actual afr is reading what your commanded is and if not - add/subtract fueling as necessary
Last edited by TCSS07; 07-27-2018 at 09:30 PM.
I did perform a test on a flat piece of road by going into top gear then doing a pull from about 2500 rpm to redline. I did this 6 times and it didn't stumble at all. Here is a log from that test session. AFR remains above 10.5:1 (but I don't mash the throttle nearly as quickly as I do when racing) road test 1 jerry tune.hpl
your rich from 6000hz - 9600hz your commanding a 12.5 afr but your wb eq ratio is at 11 afr so in those cells id start to remove fueling by entering .9 in the box and multiply cell 6k to the end of the maf and re log - the numbers should be closer and then you'll just have to modify the cells individually to fine tune
also no tune file posted - so if you have cat over temp enable and piston protection turn those off because they'll mess with wot fueling
Last edited by TCSS07; 07-27-2018 at 10:02 PM.
I'll admit that I'm a complete newb with the tuning. I had a trusted tuner helping me through the whole process but somewhere things went sour and either he's too busy for me or has died because he doesn't respond to e-mail. Now I have to figure these things out because the car is not running right. You are saying I should go the PE EQ table and richen it up from 6000 rpm and up? It's at 1.250 now, how much should I go to? 1.275? I appreciate the help BTW
no not the pe/leave that alone if you want a 12.5 afr - the pe ratio is a set and forget table - your pe ratio is set to whatever you want - boosted app i set it to 11.8 or eq ratio of 1.250 - lambda would read a .80 btw
im talking about the MAF table/that's your actual airflow model table and where you make the adjustments - you need to remove fueling because your too rich - meaning you have to much fuel - open up the scan you posted for the smooth road - and change the speed to .1 and watch your wb eq ratio 1 vs eq commanded during the pull - they should read the same give or take a .01/.02 either side but your actual is richer by about 1.5afr - so on the maf table put .9 in the box and multiply cells 6k all the way to whatever the max hz and re log - the wb eq ratio 1 vs eq commanded should be more inline and then you'll have to fine tune each of the cells to get them better inline
Last edited by TCSS07; 07-27-2018 at 10:19 PM.
What is the name of the table you're talking about? MAF Airflow vs Output Frequency? So, from 6K to 15K I multiply by .9?
Last edited by marksawatsky; 07-27-2018 at 10:25 PM.
Mass Air Flow - itll be in engine/airflow/general - maf calibration
Yup, Engine-Airflow-General-MAF Calibration and multiply the table from 6000 and up times the .9?
yeah, that's roughly 10% fuel removal and thats where id start and then fine tune from there
fyi multiplying by 1.1 would be 10% addition of fuel - if there was a lean fuel condition
always subtract fueling when rich and add fueling when lean
Thank you for this. Anything else before I go test n tune tomorrow? Talk slow, I'm not that bright
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