LC-1 reads different in HPTuners and Aeroforce

[Pulse_GTO]

Warning: Long post follows...



I have an LC-1 in my car and I decided to do more work on my VE table. I set up my HP tuners Wideband PID properly by finding my slope and ground offset values. Since I set up the LC-1 to give me 10:1 afr at 0 Volts and 18:1 afr at 5 Volts, the formula came out to (Volts/0.625)+10.
Now all I had to do was to find my ground voltage offset. I forced the LC-1 to output a value of 14.7, so I set the output voltage to a flat 2.9 volts, no matter what it was actually reading. I hook up the HPtuners scanner and I get a value of 14.62. No problem, I add 0.08 to the 10 in the formula, and I get the 14.7 I was looking for. After that I set the voltages in the LC-1 back to 0 and 5 and go out for some logs, happily thinking that I have set it up correctly.

I noticed that at idle I was reading a steady 17.52-3:1. Not surprised here, my car had the best idle qualities when it's lean.

Since I was double checking my offsets in HPtuners, I thought it would be nice to set up my Aeroforce to read from 10:1 to 18:1, down from 20:1 how it was previously set up. I did some quick math and came up with a slope of 1.6. I got this number like this (18-10)/(5-0), basically afr range divided by voltage range, same way it's described in the Aeroforce manual.
So I enter 1.6 for slope, and 10 for intersect. I force the LC-1 to give me 14.7 on the other analog output and I get 15.2. Ok, I'm off by .5, so I change the intersect to 9.5 and get 14.7 on the gauge.

So far everyhthing looks great, I'm looging, making changes, and having a great time. Until I decide to stop logging at idle, remember I was seeing a constant 17.52, and I plug in my Aeroforce in the OBDII connector. It powers up, and I'm seeing an afr in the 15s!!!

What did I do wrong? Which output is working right? I went over my math so many times, but I cannot see where I made a mistake, so I'm out of ideas.
Can anybody help?

Sorry about the long post, but I tried to include as much info as possible.

[talsayed]

1-Try to narrow your wide band,use one of the following setup

0 V = 10 AFR
5 V = 16.41 AFR [ 0.78 EIO value ]
3.67 V =14.705 AFR ( setup value )

0 V = 10 AFR
5 V = 17.15 AFR [ 0.6993 ]
3.29 V =14.705 AFR


0 V = 10 AFR
5 V = 18.13 AFR [ 0.615 ]
2.9 V =14.715 AFR

2- Set response speed to 1/6 or even 1/3.

3-Creat a histogram (use it to find your offset)..See attached image

4-Always check your wide band offset while the engine is running .

Hope this will help

[Pulse_GTO]

4-Always check your wide band offset while the engine is running .

That could be one issue.

I'll work on it more today and post up the results.

Thanks for the suggestions.