LC1 power supply question - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


MEGAsquirt A place to collectively sort out this megasquirt gizmo

Reply
 
 
 
LinkBack Thread Tools
Old 11-03-2008, 10:21 PM   #1
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default 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.
Joe Perez is online now   Reply With Quote
Old 11-03-2008, 10:30 PM   #2
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 248
Default

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.
patsmx5 is offline   Reply With Quote
Old 11-03-2008, 10:36 PM   #3
Elite Member
iTrader: (11)
 
Join Date: Jun 2007
Location: Overland Park, Kansas
Posts: 5,382
Total Cats: 43
Default

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.
elesjuan is offline   Reply With Quote
Old 11-03-2008, 10:52 PM   #4
Junior Member
 
Join Date: Dec 2007
Posts: 159
Total Cats: 0
Default

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.

Last edited by dynokiller90; 11-03-2008 at 11:03 PM.
dynokiller90 is offline   Reply With Quote
Old 11-03-2008, 10:58 PM   #5
Junior Member
iTrader: (4)
 
Join Date: Oct 2007
Location: santa cruz
Posts: 246
Total Cats: 0
Default

Quote:
Originally Posted by dynokiller90 View Post
tap into one of the ignition wires under the steering column ... black wire with a yellow tracer
+1

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

Then, without changing anything else, I switched to a +12 lead which is hot in Ďruní and Ďstartí (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, Iíll get an LC-1 error code but I donít know what the error is because I havenít looked it up. If I see the LED flashing, I just switch off the ignition and have another go. Then itís solid.

Itís grounded to the block with virtually everything else (MS, gauges, etc.).

It likes to be recalibrated. A lot.
chucker is offline   Reply With Quote
Old 11-03-2008, 11:17 PM   #6
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

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.
Ben is offline   Reply With Quote
Old 11-04-2008, 10:07 AM   #7
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

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?
Joe Perez is online now   Reply With Quote
Old 11-04-2008, 10:58 AM   #8
Junior Member
iTrader: (4)
 
Join Date: Oct 2007
Location: santa cruz
Posts: 246
Total Cats: 0
Default

Quote:
Originally Posted by Joe Perez View Post
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?
chucker is offline   Reply With Quote
Old 11-04-2008, 11:55 AM   #9
Supporting Vendor
 
Matt Cramer's Avatar
 
Join Date: Sep 2006
Posts: 2,266
Total Cats: 51
Default

We power the LC-1 in the red Miata from the fuel pump relay. It hasn't shown any issues from that.
Matt Cramer is offline   Reply With Quote
Old 11-04-2008, 11:55 AM   #10
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

Quote:
Originally Posted by chucker View Post
BTW- what was the cause of failure in your AEM WB?
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?
Joe Perez is online now   Reply With Quote
Old 11-04-2008, 12:03 PM   #11
Elite Member
iTrader: (15)
 
patsmx5's Avatar
 
Join Date: Aug 2007
Location: Houston, TX
Posts: 8,796
Total Cats: 248
Default

Quote:
Originally Posted by Joe Perez View Post
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.
patsmx5 is offline   Reply With Quote
Old 11-04-2008, 01:13 PM   #12
Elite Member
iTrader: (5)
 
Join Date: Mar 2007
Location: NYC
Posts: 1,997
Total Cats: 1
Default

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.
johndoe is offline   Reply With Quote
Old 11-04-2008, 01:30 PM   #13
Junior Member
iTrader: (4)
 
Join Date: Oct 2007
Location: santa cruz
Posts: 246
Total Cats: 0
Default

Quote:
Originally Posted by Joe Perez View Post
When it comes to free-air calibration, do you guys actually remove the sensor to do it?
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...
chucker is offline   Reply With Quote
Old 11-04-2008, 03:51 PM   #14
Junior Member
 
Join Date: Dec 2007
Posts: 159
Total Cats: 0
Default

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.
dynokiller90 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 57 07-19-2017 05:11 PM
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Odd Steering issue interestedofold Suspension, Brakes, Drivetrain 5 09-29-2015 02:42 PM
Missing/knock at idle, can someone point me in the right direction? Mikel MEGAsquirt 4 09-28-2015 05:46 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:27 AM.