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Old 09-28-2013, 04:44 AM   #1
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Default AFR not reading correctly.

So first, a bit of info on my setup.

I installed a Megasquirt 3 built by MS Labs (which I believe is Reverent on this forum?).
Running an LC-1 wideband sensor with an innovate motorsports gauge.

Got everything set up, and it ran great with the base tune (by great I mean there were no issues with it running, it obviously still needs to be tuned).

The issue I ran into was that on my AFR gauge it is displaying what seems to be the correct (or close to) AFR, but in tuner studio it's way off, and almost seems to be doing the opposite of what it should (when going to higher RPMs it will drop down to a VERY rich AFR, sometimes as low as 1:6).

I ran autotune just to see what it'd do, and as expected it went off of what it was displaying, and started leaning out the fuel map to the point where it sounded like I had an anti-lag system set up (I don't even have a turbo).


Any ideas on why tuner studio isn't showing the proper AFR? (or why the sensor is sending two different readings on the outputs?)
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Old 09-28-2013, 05:17 AM   #2
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Idk if it helps at all, but tuner studio seems to be receiving the correct numbers from the narrowband.
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Old 09-28-2013, 05:45 AM   #3
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Digital or analogue?
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Old 09-28-2013, 06:29 AM   #4
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Quote:
Originally Posted by triple88a View Post
Digital or analogue?
analog
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Old 09-28-2013, 08:58 AM   #5
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Are your grounds hooked up the way Reverent instructed? IIRC he's pretty specific on how the LC-1 is wired to the MS.

Further than that, you can use tools > calibrate AFR > custom AFR table to try to match the readings.

I had a similar problem (however, only about .5-.8 off) and what I did was set the idle very rich manually using the VE table, I used about 11:1. Then use the custom AFR table to adjust things until they match while rich. Write those numbers down. Then manually adjust your idle very lean, I used 16.5:1, and write those numbers down. Pop them both in and it should work decently well from there.
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Old 09-28-2013, 09:10 AM   #6
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How is your lc1 wired up? I mean, what wire goes to the ms and what wire goes to the gauge?
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Old 09-28-2013, 01:23 PM   #7
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Quote:
Originally Posted by Onyxyth View Post
Are your grounds hooked up the way Reverent instructed? IIRC he's pretty specific on how the LC-1 is wired to the MS.

Further than that, you can use tools > calibrate AFR > custom AFR table to try to match the readings.

I had a similar problem (however, only about .5-.8 off) and what I did was set the idle very rich manually using the VE table, I used about 11:1. Then use the custom AFR table to adjust things until they match while rich. Write those numbers down. Then manually adjust your idle very lean, I used 16.5:1, and write those numbers down. Pop them both in and it should work decently well from there.
That's definitely something I need to look at... the manual I got with the MS3 has two wires that are there for grounds: one being for "ground/heater ground", and the other for "analog sensor ground". However, the manual I got with the LC-1 doesn't say specifically what each one of the ground wires is actually for, just says to ground them.

Quote:
Originally Posted by thirdgen View Post
How is your lc1 wired up? I mean, what wire goes to the ms and what wire goes to the gauge?
I've got the brown wire going to the AFR gauge and the yellow going to the MS.
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Old 09-28-2013, 01:28 PM   #8
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Well since one is a sensor ground, so it should be grounded through the MS. The other can be grounded at a good spot somewhere.

Maybe rev does it differently, but you always want to ground sensors through the MS.
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Old 09-28-2013, 04:00 PM   #9
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I asked REV a similar question in an email and he told me to ground my AEM wideband through the ground labeled LC-1 heater. It is the black/yellow stripe wire in the DB37 connector. I haven't fired mine up yet though.
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Old 09-28-2013, 05:25 PM   #10
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I know that for my MTX-L the heater and sensor ground through the same wire, so that could make sense.
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Old 09-29-2013, 04:01 AM   #11
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I got it all working good now.
I ended up running the LC-1 to both the gauge AND the MS via the brown wire on the LC-1, instead of using the yellow output on the LC-1.

Got it pretty close to the target AFRs, will probably do some more tuning tomorrow. Only issue I'm having now is the idle is really weird at times... gonna create a seperate thread for that though, to keep things organised.


Anyone know why the yellow and brown wires on the LC-1 give different outputs? They're both labeled as analog outputs :S
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Old 09-29-2013, 05:08 AM   #12
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Different configurations from the controller? Perhaps one is narrowband output or something as default? No clue but u can try plugging it in the laptop and checking it out.
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Old 09-29-2013, 05:18 AM   #13
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The second wire is narrowband as default.

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