LC1 power supply question
 

I am preparing to install an LC-1 and XD-16 to replace my ailing AEM wideband. I seem to recall some conversation a while back surrounding the power supply to the LC1. Specifically, that the unit tended to "lock up" due to the voltage fluctuations during cranking, and that it was best to feed it power that was not hot during cranking.

I cannot seem to locate any reference to this thread, and it's possible I suppose that I imagined it. It seems somewhat dubious that Innovate would design a product for automotive use which couldn't tolerate some voltage fluctuations. Does anybody remember this, or better yet have any first-hand knowledge of it? All else being equal I'd prefer to power the unit from the white/red Main Relay feed, as the wires are already in place and it'll save me some frustration.

LC-1's are picky to following the directions. Directions say that power should go to it in the run position only. (not run and start). I had mine setup per the directions to the "T", power on at run only, and it worked flawlessly till I rewired the engine.....

Now, I have it so that it is hot in run or start. Reason is, if you shut it off, it takes a few seconds to warmup and come back online. If you're dataloging and it dies, and then you restart, you won't have a log of AFR's afterward. So I wire mine up so it's hot in run and start.

Worked fine for ~2 months, then one day it "broke". Famous "it reads 10.0 all the time and jumps to max lean, but it mainly just sits on 10:1 all the time". Lost it's free air calibration. Redid it and it works fine now. But I do believe the power fluctuations during cranking messed it up.

If you want fused switched power that's hot only in run, stick an "add a fuse" in the windshield washer fuse area. That's what I did originally. Simple, cheap, reversible, no cutting factory wiring, etc.

mine never locked up, it just likes to randomly recalibrate itself.


With my blower motor running and idle if I switch on the head lamps the ECU will reset, and sometimes it'll reset the calibration on the LC1. Everyone says if you follow the directions they work perfect. I'll have to try that sometime. ;)


When I get around to it I'm going to install a relay and do some dedicated electrical for it.

I know that I'm a newb here, but I have been doing this kinda thing for quite a few years. I found that if you tap into one of the ignition wires under the steering column they are pretty stable even while cranking. to say that the lc-1 is sensative to fluctuation is quite a large understatement. not only are they sensative to voltage they seem to be sensative to the amperage that is running through your supply. If it's not perfect, it just ain't going to work. personaly I tapped into a black wire with a yellow tracer. Of course that may vary from year to year or trim packages so check it out first.

you would think that the wires (power/ground) at the ecu would be stable enough but they are not. go figure huh? they just don't seem to have enough juice going through them.

+1

I initially used the not-hot-in-cranking power windows +12 due to its convenient location; it didn’t work at all. I got an error each time I fired the engine. Don’t remember what that error was.

Then, without changing anything else, I switched to a +12 lead which is hot in ‘run’ and ‘start’ (black/yellow for the buzzer under steering column -1994, p32 in schematic, if memory serves). Problem gone.

Of note: my battery is old and sometimes it can barely turn over the motor. When it gets really bogged down, I’ll get an LC-1 error code but I don’t know what the error is because I haven’t looked it up. If I see the LED flashing, I just switch off the ignition and have another go. Then it’s solid.

It’s grounded to the block with virtually everything else (MS, gauges, etc.).

It likes to be recalibrated. A lot.

Mine a has a hot when cranking lead from somewhere. It's been there for more than 2 years now, so really I do not remember its exact source. Grounds go to the cylinder head. Once fully sorted, I have never had any phantom recalibration or other issues in 2+ years.

Hmm. Perhaps this device is as sensitive as I'd feared...

It should be a relatively simple matter to put another ring terminal on the Main fuse under the hood. It's sounding like that may be the simplest answer, rather than getting myself into a protracted troubleshooting situation. I'll just stick a relay back there to switch it on some convenient wire, and let it be.

How long does the unit take to "warm up" and become fully functional from a cold start? Does this vary from a hot restart?

Takes about 20 seconds from cold. Snaps into action in about half that time in a hot restart situation. But I'm sure we'll see variation in those numbers from other users...

BTW- what was the cause of failure in your AEM WB?

We power the LC-1 in the red Miata from the fuel pump relay. It hasn't shown any issues from that.

The analog output isn't working quite right, giving rise to offset errors with the MS. I've expended considerable effort diddling the calibration values in MegaTune, but to no avail. The miscalibration seems to be inconsistent and variable- some days it's off more than others relative to the display on the gauge. It was like this back when I had an EMU as well, though the severity of the error seems to be growing- it can be off by up to about 0.7 some days. I decided to stop frustrating myself and just get a new one. I went with the LC1 as it is supposedly much faster responding.

When it comes to free-air calibration, do you guys actually remove the sensor to do it? Seems to me that if you get the car up to speed and then turn the key off while depresseing the throttle fully and allow the car to coast down, that this should pump enough "clean" air through the system to do a cal, no?

Yeah, that's all I do. Go into megatune and enable decel. fuel cut. I just bought it to like 5K in 3rd gear, let off the gas, watched the guage peg lean for 5 seconds, then hit the calibrate button. Fixed it. I'd hate to have to pull the sensor to do it cause I'd have to pick up the car to get to it.

If I remember correctly I have my power tapped at either the power windows or wipers with an add a fuse at the fuse box under the dash. Couple months with no issues.

I pull it out. It's in front of the cat so I roll onto a set of ramps, remove, calibrate, replace. Just did it in less than 10 minutes. Once a month isn't a problem. If it were in another location, I'd probably be less diligent.

During the installation, I considering omitting the included LED and momentary switch. Glad I decided to include them as they make life easier for calibration and error warnings...

or you can just do it after it's been sitting over night. before you start the car.
I know it's just anecdotal, but I watched it to see how long it took to read dead lean after shut down. It wasn't all that long, maybe 20 min or so. that's with a fairly open
3" exhaust. sensor is mounted at the inlet to the cat. so I would think a few good hours of sitting would be enough, or you could allways stick a fan behind the car to draw air out of the exhaust system.