Crazy AFR fluctuations

K-Series Programmable ECU installation questions / support issues
spoon.ap1
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Crazy AFR fluctuations

Post by spoon.ap1 »

Just started having this idle fluctuation issue recently. It seems that when the car is idling, the AFR's are all over the place but not only that, it varies from 10 - 29 on the data log but does not register on the gauge. I disabled and unplugged the factory O2 sensors and also ordered a replacement harness from the gauge to the sensor. I also tried to run the car in open loop without the wideband connected. Anyone have this problem ever? I'm using Analog0 to run my AEM UEGO gauge which is all plug and play. Also, K-pro and AEM AF readings match.

The voltage (blue) looks really stable but for some reason the AF is fluctuating like crazy.
Image

Below I posted two separate datalogs. "Squamish" is about 2hours long and the other one labelled "today" is only a couple minutes long.

https://www.dropbox....uamish.kdl?dl=0

https://www.dropbox..../today.kdl?dl=0


Here is the calibration:

https://www.dropbox....eltune.kal?dl=0


THANKS IN ADVANCE!!!
Last edited by spoon.ap1 on Tue Oct 11, 2016 10:16 am, edited 1 time in total.
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Hondata
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Re: Crazy AFR fluctuations

Post by Hondata »

The links don't work.
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Re: Crazy AFR fluctuations

Post by Hondata »

I'd suggest putting a voltmeter on the wideband output, and see if the voltage is swinging from 0V to 5V. If so, it is the wideband.
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spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

Hondata wrote:I'd suggest putting a voltmeter on the wideband output, and see if the voltage is swinging from 0V to 5V. If so, it is the wideband.
Haven't tried that yet but I've ruled out the wideband by using the factory o2 sensors in open loop resulting in the same driveability.
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Re: Crazy AFR fluctuations

Post by Hondata »

I don't think the wideband is accurately measuring the lambda. The reasons are that I don't see a corresponding change on the injector pulse when the wideband voltage swings, also that the wideband swing is very rapid and extreme (full lean to full rich), and finally it is under conditions which would give a misfire but I can't see any misfire on the rpm channel. Look at 1:07:17 to see what I mean.
BTW is Squamish.kdl from Squamish BC?
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spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

I see, I'll double check the voltage at the gauge. What do suggest if that doesn't seem to be the fix?

Yeah it's Squamish, BC haha. Are you from Canada?
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Re: Crazy AFR fluctuations

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Nope, but I know Squamish quite well.
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spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

Nice!

Okay, so the gauge seems to be fine. I ordered some EV6 injector pins and plugs(bosch injectors) to directly crimp them on to the OEM wiring because I'm also getting a heavy fuel odour from outside of the car. Assuming maybe the conversion plugs are faulty.

Edit: repined the connectors but still have same issue
spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

Checked the gauge again. It's reading 2.75 volts which is too high, it should be reading 2.35 volts. Does that sound alarming enough?
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Re: Crazy AFR fluctuations

Post by Hondata »

How have you got the wideband wired up?
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spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

I used an "add a circuit" under the dash that allows you to add another fuse off of for switched power. The wire for the signal going to :Analog 0".
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Re: Crazy AFR fluctuations

Post by Hondata »

How have you grounded the wideband?
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spoon.ap1
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Re: Crazy AFR fluctuations

Post by spoon.ap1 »

It's grounded with one of the nuts on the steering column under the dash.
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Re: Crazy AFR fluctuations

Post by Hondata »

It needs to be grounded to the same place as the ECU, which on the S2000 is on the back of the cylinder under the cowl. Otherwise you get a large ground loop and possible voltage offsets. Almost all widebands are not well designed as they shunt all the heater current down the same ground as the analog output, but adding in a ground loop does not help.
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