AFR calibration / offset?

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fordfanboi
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AFR calibration / offset?

Post by fordfanboi »

Went to the Dyno last week and found that my wideband O2 is reading 1.5 points leaner than actual. Is there a value somewhere I can change to offset the incoming wideband O2 values? For the moment, I just set all my AFR targets 1.5 lower.

Thanks!
MS II v3.0 (2.920), 408ci, Holley 900cfm TBI, Victor Jr, Mech Roller 254/260@0.050 - 0.642/0.578
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LT401Vette
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Re: AFR calibration / offset?

Post by LT401Vette »

If it is a linear WB which most are, you can calibrate it with offset AFR's to get a shift in your reading.

Usually when the read different it is due to grounding.
Phil Tobin
EFI Analytics, helping to simplify EFI with Next Generation tuning software.
http://www.tunerstudio.com/
http://www.efiAnalytics.com/MegaLogViewer/
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fordfanboi
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Re: AFR calibration / offset?

Post by fordfanboi »

LT401Vette wrote:If it is a linear WB which most are, you can calibrate it with offset AFR's to get a shift in your reading.

Usually when the read different it is due to grounding.
It's an Innovate LC-1. The Dyno shop stuffed a vacuum probe up the tailpipe where it dumps in front of tire ( I'm running glasspacks so should be accurate ) and my readings were 1.5 points leaner across the board.

So, I calibrate it the way I already did by shifting all of my AFR targets in the table or was there a single value I can enter somewhere to shift everything?

Thanks!
MS II v3.0 (2.920), 408ci, Holley 900cfm TBI, Victor Jr, Mech Roller 254/260@0.050 - 0.642/0.578
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LT401Vette
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Re: AFR calibration / offset?

Post by LT401Vette »

I’m sorry for the delayed response, I have been away.

You can go into:
Tools --> Calibrate AFR

and use a custom Linear, then shift the AFR values there by the 1.5.
That will make your AFR read consistent with the other.
1.5 is a pretty big discrepancy. Are you sure his was reading correctly?
Phil Tobin
EFI Analytics, helping to simplify EFI with Next Generation tuning software.
http://www.tunerstudio.com/
http://www.efiAnalytics.com/MegaLogViewer/
Android Shadow Dash MS: http://tunerstudio.com/index.php/shadowdashmsmenu
fordfanboi
Helpful Squirter
Posts: 74
Joined: Mon Dec 19, 2005 11:36 pm
Location: Central Texas
Contact:

Re: AFR calibration / offset?

Post by fordfanboi »

LT401Vette wrote:I’m sorry for the delayed response, I have been away.

You can go into:
Tools --> Calibrate AFR

and use a custom Linear, then shift the AFR values there by the 1.5.
That will make your AFR read consistent with the other.
1.5 is a pretty big discrepancy. Are you sure his was reading correctly?
Thanks - I'll give that a shot.

I've felt an intermittent lean stumble at 14:1 for years and wasn't sure why. It started to make sense when I was gaining power with each pull by getting richer than 12.5:1 on my Wideband O2. The 3 pulls started at 14:1 on his ( 12.5 on mine ) and gained 10+ HP each pull by adding more fuel and nearing 12.5:1 on his ( 11.0:1 on mine ). The exhaust shop installed my O2 sensor in a bad spot and I'm afraid condensation has pooled in it over the years. I'll be rebuilding my exhaust from the headers back this year, so I'll swap the sensor then. This offset should help me for the time being. TY!
MS II v3.0 (2.920), 408ci, Holley 900cfm TBI, Victor Jr, Mech Roller 254/260@0.050 - 0.642/0.578
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