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22.4 a/f on deceleration?

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Old Jun 26, 2008, 07:21 PM
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22.4 a/f on deceleration?

i just installed a wbo2, and it seems to be right on while driving, but when i let off the gas it jumps to 22.4 and stays there until i either put the car in neutral or press the gas again. when the car is sitting idle, it idles perfectly right around 14.7any ideas?
Old Jun 26, 2008, 07:24 PM
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Totally normal for your car to go lean when letting off the gas. Nothing to worry about.
Old Jun 26, 2008, 07:24 PM
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Normal.
Old Jun 26, 2008, 07:25 PM
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AAAAHHHHH!!!! That's so funny! I just got back ten minutes ago from doing some logs and I noticed the same thing. I was going do some searching before posting something but you did it for me. Same exact issue. It seems right on when driving and idle but deceleration causes is to jump up to 22.4 and stay there.
Old Jun 26, 2008, 07:28 PM
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Your injectors turn off during decel and your wbo2 is seeing free air.
Old Jun 26, 2008, 07:28 PM
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yea i did a quick search and couldnt find anything...

for some reason i was thinking 22.4 was extremely rich, not lean...oops
Old Jun 26, 2008, 07:29 PM
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Originally Posted by kstpeter33
i just installed a wbo2, and it seems to be right on while driving, but when i let off the gas it jumps to 22.4 and stays there until i either put the car in neutral or press the gas again. when the car is sitting idle, it idles perfectly right around 14.7any ideas?

Quick, easy, simply:

Fuel cut. The value is the leanest condition which your WB will read. While you decel your drivetrain is turning your engine like a compressor pump. When you pull the clutch and put the mission in neutral the engine will go back to idle condition.
Old Jun 26, 2008, 07:30 PM
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Originally Posted by kstpeter33
yea i did a quick search and couldnt find anything...

for some reason i was thinking 22.4 was extremely rich, not lean...oops
That's okay I'm learning as well. I thinks it's lbs/air to lbs/fuel but that could be a lambda reading. I'll figure it out eventually. Bigger is leaner.....I think I can remember that!!
Old Jun 26, 2008, 07:47 PM
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hehe........baby steps guys.....LOL

we was all there
Old Jun 26, 2008, 09:16 PM
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Originally Posted by Jon91TSi
Your injectors turn off during decel and your wbo2 is seeing free air.
Old Jun 26, 2008, 09:31 PM
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If I turn my ignition off during decel (wbo2 still on) my afr does not change, and I sure as hell know my injectors aren't doing anything.

EDIT: Just looked at one of my logs and they aren't off 100% still IPW of 1.02 but that probably wouldnt be enough for the wb to see any fuel during decel. My bad.

Last edited by Jon91TSi; Jun 26, 2008 at 09:35 PM.
Old Jun 26, 2008, 09:58 PM
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Originally Posted by Dapper Dan
Ive actually heard it is normal for most cars to do this. The injectors shut off until about 1500rpms during decel.
Old Jun 27, 2008, 04:31 AM
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Injectors do not fire under negative load conditions until they begin to affect the target idle. We utilize this condition all the time to increase fuel economy when designing software for automated manuals.
Old Jun 27, 2008, 07:35 AM
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Originally Posted by topnitroracer
Injectors do not fire under negative load conditions until they begin to affect the target idle. We utilize this condition all the time to increase fuel economy when designing software for automated manuals.
So does that mean when going down a hill Its better to leave it in gear and coast down, than to pop it in neutral and coast down? For gas saving wise*
Old Jun 27, 2008, 07:40 AM
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Originally Posted by douggsx
So does that mean when going down a hill Its better to leave it in gear and coast down, than to pop it in neutral and coast down? For gas saving wise*
Correct.


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