Problem with wideband A/D accuracy

[thunder550]

I'm using an LC-1. I am having a problem with analog input signal consistency and accuracy. I have EFILive connected to analog out 2 on the LC-1, and a standalone gauge connected to analog out 1. It is a DynoTune Nitrous gauge that is supposed to be calibrated to 1.00V at 10.00 AFR and 2.00V at 20.00 AFR. I checked the analog out calibration on the LC-1 and it is set correctly. Analog out 2 (EFILive) is set to 0.00V at 7.35 AFR and 5.00V at 22.35 AFR, according to the EFILive manual.

Here's the problem I'm having:

EFILive is reading between 0.6 and 0.7 AFR richer than the digital out provided by Innovate's Logworks software with the digital connection. My standalone gauge is reading between 0.1 and 0.2 AFR leaner. I don't understand what's going on.

Here's an example:

Digital out (which I am assuming is 100% accurate) is reading 14.7
EFILive tells me 14.1
Gauge tells me 14.9

I have tried tweaking the analog output voltages on the LC-1 to get everything to match. When I do this I can usually get them to match. Problem is, next time I get into the truck and check everything, it's all off again. It's like there's some variable voltage offset that is screwing with everything. I have the gauge, the wideband, and the EFILive wiring all grounded to the same grounding block, along with a lot of other interior accessories (radar detector, gauges, etc etc). Could those other devices be causing the problem? I'm frustrated trying to get all this crap to match, and I'm looking for ideas. Thanks.

[mr.prick]

try calibrating your AD outs.

[Chevy366]

I have noticed the same thing , my LC-1 always reads the same voltage at the AD out puts , but he V2 when calibrated reads correct for as long as you don't kill the engine , then shut the engine off and off it is by about the same margin you speak of sometimes more .
Maybe response time is different between the two devices (gage , V2) ?
I think the LC-1 is most accurate at the serial connection , I would trust the serial reading through Log Works before anything else , be glad when the V2 can use that signal .
Look at VE table done with a AEM or PLX , they will be spiky , the LC-1 seems to do a much better job when AutoVEing . My2.$

[thunder550]

What voltage source are you using for the analog input calibration? I thought about doing that, but I don't know where I'd get a consistent voltage as small as they are looking for.

[joecar]

You can use the LC-1 (program it's output(s) to a flat constant voltage, and check what V2 reads.

Have you seen this (it's tucked away in the FlashScan V2 subsubforum): showthread.php?t=4593 (http://forum.efilive.com/showthread.php?t=4593)

[Chevy366]

What voltage source are you using for the analog input calibration? I thought about doing that, but I don't know where I'd get a consistent voltage as small as they are looking for.
I have a double fuse holder that allow you to tap a fuse slot and not lose the fuse but also supplies a 12v additional fused output .
I grounded to the engine block just under the alternator , there are two places there to ground to , I ran a black wire to cab form that location for the V2 and used the yellow as AD1 .
EFILive calls for Analog 2 to 1v=10 and 2v=20 and then Analog 1 0.88833v=10 and 4.12677v=20 .
The V2 process is somewhat strange the way you have to set it up , flat voltage 1v check with Ohm and enter value into V2 , then set to 4v same thing enter into V2 .
Some day the V2 will connect directly to the LC-1 serial output .

[mr.prick]

Some day :rolleyes:

[thunder550]

OK well I calibrated the A/D input tonight and everything seems to be working perfectly :) I also changed the WB to read 0v at 10.00 and 5v at 20.00 AFR instead of the standard LC-1 settings of 0v at 7.35 and 5v at 22.35 or whatever. Fixed the sae_generic.txt file as necessary as well. Everything seems to be near perfect. I started by running a multimeter across the analog out wires from the LC-1 and logging the ext.ad1 voltage at the same time. There was about a 0.2v difference between the voltage from EFILive and the voltage from the multimeter. I'm sure that's what was causing the problems. Thanks for the help :)

BTW, the LC-1 was my calibration voltage source. I programed it to read 1.5V across the entire AFR range first, then changed it to read 4.0V across the entire AFR range. Works pretty handy :)