LC1-key on engine off 7.4 then goes to 21.3(sometimes 21.9 max)???

[Snyper]

I know the range is 7.35 to 22.x but it never goes above 21.3 and thats with the car off (even if I let it sit over night) I changed the grounding location to its own spot and it didn't affect it at all..Any ideas on why this is happening? Even a free air cal brings it to one of those two numbers.

[Crisis]

I'm guessing the LC1 controller is set up for a nominal ~14v DC input voltage. When you car is off the battery is suppling 12V. I don't know how well it is regulated inside, but it would make sense that the reference 5v signal changes when the input changes. You only need a 0.05v change in the 5v output to get 22.0 to roughly 21.3

I might be wrong and someone correct me if I am.

I had the same issue with an LM1 couple of years ago but on the dyno comparing graphs, my LM1 log was only ~2-3% off of the dyno's calibrated widebands (dedicated power supplies and grounding and new sensors). So I didn't bother looking into it.

[Snyper]

Thats what I was thinking. My voltage is around 11.8x V with the key on car off..

[CLRD4TO]

How steady are your afr readings? I have the lc-1 with the digital gauge. Its always moving at least a couple tenths, never solid at a certain number for even one whole second. Engine off it was stay within one tenth. Im curious if I should calibrate it at 14v myself.

[Snyper]

How steady are your afr readings? I have the lc-1 with the digital gauge. Its always moving at least a couple tenths, never solid at a certain number for even one whole second. Engine off it was stay within one tenth. Im curious if I should calibrate it at 14v myself.

engine off? doesnt move.

[TheBlurLS1]

The first thing I would do with the LC-1 is a free-air calibration. Every time I've seen an LC-1 start spitting out crazy numbers, it usually fixes it. You'll have to wire up the little calibration button if you haven't done it already, and I always just take the sensor out of the pipe completely for the calibration.

Be careful doing that, because that SOB gets hot as hell.

[DSteck]

I hope you aren't trying to use the built in configuration for the LC-1 in HP Tuners. Also, it's never going to output exactly 0V or 5V... which is why you're never going to see it spit out a number that is the peak or minimum of it's quoted range.

It's going to read the leanest it can register when the engine isn't running... I don't understand what you think is wrong.

[Snyper]

Well it matches what the LC-1 gauge says. And even when I free air calibrate it it goes to a max of 21.9 or sometimes 21.3 My brothers goes to over 22.

[DSteck]

I don't see why you care. If it reads normal while you're actually tuning, then WGAF. Mine reads a leanest reading of 17.9, even though it's set up to peak out at 18.