LM1 users

[hpcubed]

Taken from post from mistermike:
"I hooked up the LM Programming software and the graph showed an AFR of 7.35 at 0 volts and 22.39 at 5 volts as shown below. 14.7 should be at 2.45 volts.

Faced with the choice of programming the LC-1 for 0.5 volts at the 7.35 AFR or re-doing the calculated PIDs, I took the lazy approach and simply made the LC-1 fit the PID, shown in the second graph. Stoich now hits at 2.70 volts.

I believe for a factory default LC-1 the formulas should be a simpler:
"({EXT.AD1}*3)+7.35"
and
"({EXT.AD2}*3)+7.35"

If you're using LC-1s, I suggest first checking them with the supplied utility . If they show 7.35 AFR at 0 volts as mine did, then you need to make the correction to the LC-1 or the PID. "

This seems to work pretty well.

[hpcubed]

Not to hijack but- while we are talking about the LM1: I have noticed that when I first start my car (open loop with commanded AFR = 12.5 across the board) I notice that initially my LM1 is showing lean (~14:1). Then after the car runs for a while the AFR from LM1 drops closer to what is commanded. Anyone else seeing this?

[Tordne]

Not to hijack but- while we are talking about the LM1: I have noticed that when I first start my car (open loop with commanded AFR = 12.5 across the board) I notice that initially my LM1 is showing lean (~14:1). Then after the car runs for a while the AFR from LM1 drops closer to what is commanded. Anyone else seeing this?

Often it is recommended to leave your key at the accessory position for 30-40 seconds before starting the vehicle. This give the WB element time to warm up, before which time they are apparently not accurate. This is true for the PLX devices, but I imagine for LC/LM also.

Cheers,

[joecar]

Often it is recommended to leave your key at the accessory position for 30-40 seconds before starting the vehicle. This give the WB element time to warm up, before which time they are apparently not accurate. This is true for the PLX devices, but I imagine for LC/LM also.

Cheers,

This is also true of the NBH02S's.
Cheers
Joe

[hpcubed]

The LM1's read-out indicates when the heater is warming up. Mine seems to take about 2-4 min. after the the LM1 indicates that the element is warm before it start showing what I assume is the correct AFR. Any corrections to the open loop AFR(ie coolant temp, air intake temp) should show up while logging the commanded AFR correct?

[Highlander]

Set .5 Volt -----equals 10 AFR

Set 4.5 Volts --equals 18 AFR

Firmware is the newest as I just updated it on Friday.

by using this.. how did you come up with the formula you where using? trial and error?

[Dirk Diggler]

Using the slope intercept formulat

[XLR8NSS]

Here is a new formula I am using and it apprears to be spot on. I have checked at several AFR ranges and all appear to be within .1.


AFR = ({EXT.AD1}*1.598)+10

Ok, I've tried using the default calibration and the LM-1 pid and it didn't work at all.

Then I used the expression you posted above and recal'd the LM1 to the voltages you used. That seems to work great at idle but, at WOT it is about .5 off. The LM-1 reads 11.7 while EFIlive reads 12.2. At idle both read 14.6:1

Can you explain how you came up with that formula so that I can attempt to figure one out for myself that is closer for my setup.

Has anyone else succefully setup a LM-1 with EFILive?

I'm about to give up on this thing, sell it and buy a LC-1. :lol:

[Extinct]

Yeah, got mine working no issues. I did talk to Black02SS a little about his correction formula so I understood it.

Basically the issue is one of potential voltage offset between what the LM1 box is putting out (or thinks it is putting out) and the voltage that Live reads.

After some thinking about it and playing around with it, here is what I did.

I set up the LM1 to output the same voltage regardless of AFR, basically you put the same # in the voltage box at both positions for the wideband channel. I did this 5 times, in steps of 1.0 volts - .5, 1.5, 2.5, etc. I then started the car and logged the voltage that Live was reading. It was off by a little bit, not much really, but I would rev the engine in the garage a little during logging just to make sure any alternator voltage effects were taken into account. I really did not see output voltage vary more than .1-.2 volts.

Anyway, then I made this little excel table that I used to derive a new wideband equation for. Basically all it does is use the measured voltage and derive a new slope and intercept so that the AFR matches what the LM1 is trying to tell it. On mine, I measured less than .05 error, so although it didn't really need correcting once I had the formula I used it anyway

Hope this helps ! See attached file !

[XLR8NSS]

Thanks alot. I will try that tomorrow.