Kangarooing at low revs
Thread Starter
Staging Lane
Joined: Sep 2018
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Kangarooing at low revs Hi,
I have an issue where my vehicle isn't smooth when accelerating at really low rpm. Usually from 900 to about 1750 rpm. It's an LQ9 from an auto that's now mated to a manual and I'm wondering if there's some calibration that might need tweaking somewhere that's still set up for an Auto?
I have an issue where my vehicle isn't smooth when accelerating at really low rpm. Usually from 900 to about 1750 rpm. It's an LQ9 from an auto that's now mated to a manual and I'm wondering if there's some calibration that might need tweaking somewhere that's still set up for an Auto?
Thread Starter
Staging Lane
Joined: Sep 2018
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Well yes, that's what I'm trying to achieve. I guess I'm asking if anyone knows of any specific calibration differences (and in what area) required for a manual car vs an auto. I doubt an auto would spend as much time at very low rpm nor need such fine throttle control as a manual.
The best way to descibe it is that it feels too lean as if the acceleration enrichment at light load and small throttle angles isnt aggressive enough.
The best way to descibe it is that it feels too lean as if the acceleration enrichment at light load and small throttle angles isnt aggressive enough.
Thread Starter
Staging Lane
Joined: Sep 2018
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I've tried but I can't convert from raw voltage in vcm scanner. I've asked but noone has replied to my questions and I'm stuck. I've connected my LM-2 through the unused AC wire and get a voltage that fluctuates around 2.35 at idle. There's no option to transform the input as the instructions I've read say there should be. It's an 06-07 P59.
TECH Fanatic
Joined: Jan 2018
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Do you know whether it's using the high-octane or low-octane timing tables? Timing is a bit low in the low-octane table.
I've accidentally induced surging by puliing timing too much timing in the cruise / mild-acceleration area. (At the time, I was trying to fix what turned out to be false knock.) Your high-octane timing is within a couple degrees of what I'm running in my C5 right now, but your low-octane timing is about ten degrees lower.
I've accidentally induced surging by puliing timing too much timing in the cruise / mild-acceleration area. (At the time, I was trying to fix what turned out to be false knock.) Your high-octane timing is within a couple degrees of what I'm running in my C5 right now, but your low-octane timing is about ten degrees lower.
Originally Posted by Sidewaysste
I've tried but I can't convert from raw voltage in vcm scanner. I've asked but noone has replied to my questions and I'm stuck. I've connected my LM-2 through the unused AC wire and get a voltage that fluctuates around 2.35 at idle. There's no option to transform the input as the instructions I've read say there should be. It's an 06-07 P59.
You use a custom math function. You take the volts vs AFR from the instructions and draw a y=Mx+B line, enter that as your function where Y is AFR and x is input volts. Then you will have AFR.
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Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 89
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Yes, I've read the help files and I'm still stuck. That's why I'm asking for help on a forum. From what I've read, I should be able to transform an input and the examples I've read use either the AC input or EGR input and then transform it to read AFR.
My 2007 LQ9 doesn't have EGR. That means the only other 0-5v input spare I've been able to find is the AC. When I go into VCM Scanner, there isn't the option to do anything with it other than alter the colour of text.
I'm still stuck. I would *really* appreciate if someone could explain to a newbie what I'm doing wrong both in terms of setting it up and in terms of trying to find the right information.
Thread Starter
Staging Lane
Joined: Sep 2018
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It appears that V3.X is completely different from the earlier VCM so nearly all of the information out there is incorrect.
I've connected in on pin B55 and enabled EGR.
I now have an AFR graph in VCM
It still reads as EGR and Volts in the table on the left though. Is this to be expected?
You should log for afr commanded. If it's in the 14.xx range that means it's in closed loop (which it usually is at low rpm), so fueling is being controlled by the narrowband O2s. Then you can check the fuel trims separately for each bank, if one is way off then probably a leak or bad O2 sensor. You should also tune the VE table just using fuel trims if you haven't already. High LTFT values could mean an intake leak. Wideband would be more useful for PE tuning.
Thread Starter
Staging Lane
Joined: Sep 2018
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Thank you for the advice.
I'm struggling to figure out which channels are sensor values and which are commanded values.
I've attached my current setup in VCM.
Can anyone recommend some good youtube tutorials for the basics of VCM? I found some a while back that went into reading and utilising the historgrams but I can't remember what they were called.
I'm struggling to figure out which channels are sensor values and which are commanded values.
I've attached my current setup in VCM.
Can anyone recommend some good youtube tutorials for the basics of VCM? I found some a while back that went into reading and utilising the historgrams but I can't remember what they were called.
It looks like your engine is not anything super complicated. I suggest watching some tutorials on using your short and long term fuel trims to adjust your fueling. Those histograms already exist in the default file and will get you started on dialing in your car faster while you learn how to build histograms and custom functions.
Thread Starter
Staging Lane
Joined: Sep 2018
Posts: 89
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It looks like your engine is not anything super complicated. I suggest watching some tutorials on using your short and long term fuel trims to adjust your fueling. Those histograms already exist in the default file and will get you started on dialing in your car faster while you learn how to build histograms and custom functions.
I have some LS3 heads, car intake manifold and LS3 injectors to fit when I've bought a suitable camshaft and gaskets.
That still would be easy to tune via fuel trims. Don't get me wrong, WB ftw. but in the interest of getting you started, that would be the simplest thing.
One of the members on here has some of the best videos out. I've spent a lot of $ learning to tune and you can learn more from his videos than a lot of the places I paid to learn from. Check out his stuff, here is a link to one. BTW, he is a hell of a nice guy.