Lambda reading when rowing gears is off

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Lambda reading when rowing gears is off

Postby 88a5tq » Wed Apr 19, 2017 10:41 am

Logging while driving through several gears during a hard pull shows some pretty wonky lambda results that err on the rich side. Pulls in each gear separately results in satisfactory lambda readings. Who can relate and is this due to a brief vacuum on my direct port meth injection (using 2 solenoids)? Is this even a problem? I'll post an example log from yesterday later today.
Thanks guys
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Wed Apr 19, 2017 10:43 am

The first gear of the hard pull is normal and all consecutive gears appear rich. I have noticed the same happens if I pull only one gear, and engine brake after, that it goes rich also.
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Re: Lambda reading when rowing gears is off

Postby ChrisAudi80 » Wed Apr 19, 2017 10:43 pm

What happens is that when you let go of the gas pedal, you suddenly cut off air, but there is still a lot of fuel, so it goes real rich. Also because of the fuel film effect. However, lambda should then go totally lean because the residual fuel has been "sucked" through.
Do you see this? Or only rich? If so, you need to lower VE in the lowest kpa row.
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Thu Apr 20, 2017 6:21 am

Hmmmmm thanks for your reply. I couldn't find an acceptable log on I'll redo it today after work.

From memory, I think it stays rich for several seconds if I continue to engine braking, it slowly would climb to be lean. I'll try your suggestion as well, thanks!
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Fri Sep 01, 2017 11:20 am

Also something to note.. I've never seen anyone mess with the fuel film settings pane in VEMS. I wander if it's already how it should be in the base file I was given and copied for my current tune??
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Re: Lambda reading when rowing gears is off

Postby ChrisAudi80 » Sun Sep 03, 2017 3:07 am

88a5tq wrote:Also something to note.. I've never seen anyone mess with the fuel film settings pane in VEMS. I wander if it's already how it should be in the base file I was given and copied for my current tune??


I briefly tried doing something with the fuel film settings, but it just made the lambda values go all over the place. Megasquirt has clearer settings for this. Just leave it. The helpfile is incomprehensible when it comes to this.
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Wed Sep 06, 2017 3:06 am

Lol that's more experience than I have with it at least. Thanks
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Re: Lambda reading when rowing gears is off

Postby ChrisAudi80 » Fri Sep 22, 2017 10:07 am

Have you enabled over run fuel cut? If not, try this:
0 kpa, cut above 1800rpm, enable 1600. That should take care of the rich between shifts stuff.
Works a charm.

No, I didn't figure it out myself. Just read a lot and asked some questions on FB.
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Fri Sep 22, 2017 10:54 am

Actually the bizarre part is I do have it enabled LOL
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Re: Lambda reading when rowing gears is off

Postby ChrisAudi80 » Fri Sep 29, 2017 12:51 am

88a5tq wrote:Actually the bizarre part is I do have it enabled LOL

That is odd.

You still have this over rich issue?
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Re: Lambda reading when rowing gears is off

Postby 88a5tq » Fri Sep 29, 2017 7:15 am

I can't post a pic of my log so I can't even be sure it's a reasonable amount of time to run rich. It seems the same though. My adjustable fuel cut is set to disabled and my settings for over run are 16 kPa and 1600/1300 rpm. Thanks for following along Chris :)
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Re: Lambda reading when rowing gears is off

Postby ChrisAudi80 » Thu Oct 05, 2017 5:26 am

88a5tq wrote:I can't post a pic of my log so I can't even be sure it's a reasonable amount of time to run rich. It seems the same though. My adjustable fuel cut is set to disabled and my settings for over run are 16 kPa and 1600/1300 rpm. Thanks for following along Chris :)



Do you ever hit 16kpa? Try 0 kpa and the same rpm settings. Watch the injector pulse width go to 0.0ms. Sometimes when you are pushing hard and shifting fast, overrun fuel cut does not have time to engage and so go briefly lean. There's just too much fuel. I see it sometimes too in my logs.
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