AFR differs from the gauge on High RPM

s300 and SManager software questions & answers
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solosaniok
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Joined: Mon Mar 19, 2018 12:32 pm

AFR differs from the gauge on High RPM

Post by solosaniok » Mon Mar 19, 2018 1:23 pm

S300, P30JDM ECU, Innovate LC2 connected to D14 power connected to A25 and ground to the ecu ground.
I have aligned the s300 AFR to the gauge AFR on idle, every thing looks nice.
When I am recording a datalog for a particular run to 8k RPM I see that the AFR on the gauge and the AFR in the s300 datalog differs for the higher rpm (S300 AFR are showing like 0.7-0.8 AFR less than the gauge)
Can you please tell me if someone also have this issue and if there is a known fix for that?

TTR
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Re: AFR differs from the gauge on High RPM

Post by TTR » Tue Mar 20, 2018 2:22 pm

What input are you using to log AFR into the software?

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Spunkster
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Re: AFR differs from the gauge on High RPM

Post by Spunkster » Tue Mar 20, 2018 2:28 pm

Do not use D14 as it cannot see the full voltage range. Use ELD instead.

solosaniok
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Re: AFR differs from the gauge on High RPM

Post by solosaniok » Tue Mar 20, 2018 11:38 pm

I use D14, yes it does not log anything above 3.7 V but in AFR this is above 17-18:1 and I never need or use this AFR, everythig bellow is fine.
To match the gauge AFR and the smanager AFR at high RPM I use 0.7 V offset but in this case i have discrepancy on low and idle.

crluver123
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Re: AFR differs from the gauge on High RPM

Post by crluver123 » Wed Mar 21, 2018 6:11 am

try moving the wideband ground wire[s] to a different location. And clean and tighten the ecu grounds on the engine.
Usually when there's an offset between gauge reading and ecu reading, it's because of a difference in the grounds.

what wire are you using as a power supply to the wideband?
What wideband setup/gauge are you using?

solosaniok
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Re: AFR differs from the gauge on High RPM

Post by solosaniok » Wed Mar 21, 2018 6:45 am

I am using Innovate LC2 with bosch lsu 4.2, standard innovate cable for the ground

creizlein
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Re: AFR differs from the gauge on High RPM

Post by creizlein » Wed Mar 21, 2018 12:24 pm

I had a similar experience with this, it was really hard to match the gauge reading and had to adjust the offset all the time, and my problems went away when i wired the Wideband to the same +12v/GND as the ecu, cant recall exactly which pin numbers they were but there are some docs in here that recommend doing that.
Upon changing the power source my offset is always steady and readings are 98% accurate to the gauge. hope it helps

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