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LC1 connections question

Old 12-19-2007, 09:11 PM
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Default LC1 connections question

Im installing my LC1 WB and I have a couple of questions. It has the digital gauge.
WHAT IM DOING:

-I want the gauge, led and push button to be below the radio where I have a carbon fiber plate. I mounted all these parts on the plate and it looks clean.
- I would like to use grounds that are in proximity of the radio, that way I wont have extra wires on the engine bay.
- I want to have the push button and led wired permanently into the black calibration wire. (the manual says "connect a MOMENTARY push-button between the ground and the BLACK calibration wire). Is this ground the same one I'll be using for the blue and white wires?
- I think using the chassis for ground would be convenient. Can I put the grounds to the bolts of the shifter boot?

QUESTIONS:

- Can I put the grounds to the bolts of the shifter boot?
- Can the LED light and the push button be permanently wired in?
- What wire should I tap into so the gauge dims when I turn my headlights on?
-Can the gauge and the WB be wired to the same power source?


CONFIGURATION QUESTIONS:

-If I change my wideband setting for 0V=10:1 and 5V=20:0 how many volts is 14.7:1? Is it 3.675 volts?
- Should I wire my 02 sensor the cable that feed the original narrow band or just use pin # 10 on the center connector?
- Which cable is connector #10?
- The cable that connects to MS is the BROWN cable, right?

Thanks, sorry for the million questions
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Old 12-19-2007, 09:14 PM
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Go read:
https://www.miataturbo.net/forum/sho...highlight=LC-1

No you cannot ground them at the shifter boot. All three things need to be grounded at the stock ECU location on the engine at the intake manifold.
Yes they can be wired in permanently i believe.
The gauge and wideband can be powered by the same source.
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Old 12-20-2007, 09:23 AM
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Originally Posted by 90turboMX5

QUESTIONS:

- Can I put the grounds to the bolts of the shifter boot?
- Can the LED light and the push button be permanently wired in?
- What wire should I tap into so the gauge dims when I turn my headlights on?
-Can the gauge and the WB be wired to the same power source?
1. No, You shouldn't. It should be on the same grounds as the MS. But on the block. Dont ground anything to the radio.
2. Yes, you can and you should. Personally I wouldnt put it in a location where you can easily hit the button. if you do, youre gonna have a problem.
3. If your car has a day time running light plug like my 97, you can tap into the White/black stripe wire at that plug.
4. Yes



CONFIGURATION QUESTIONS:

-If I change my wideband setting for 0V=10:1 and 5V=20:0 how many volts is 14.7:1? Is it 3.675 volts?
- Should I wire my 02 sensor the cable that feed the original narrow band or just use pin # 10 on the center connector?
- Which cable is connector #10?
- The cable that connects to MS is the BROWN cable, right?

Thanks, sorry for the million questions
1. No idea. Why does it matter?
2. Depends. If the wire from the wideband is in the bay then sure, reuse the original wire. If not then connect it directly.
3. No clue.
4. Could be either, yellow or brown just make sure you configure them properly. The MS will need 0v = 10,5v = 20. The LC1 DB gauge will need the factory settings of 0v = 7.35, 5v = 22.99.
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Old 12-20-2007, 11:29 AM
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Addressing the few that haven't been answered
-If I change my wideband setting for 0V=10:1 and 5V=20:0 how many volts is 14.7:1? Is it 3.675 volts?
Assuming a linear scaling with 0v = 10 and 5v = 20, then 2.35v = 14.7 AFR.

The cable that connects to MS is the BROWN cable, right?
Yes, assuming that you recalibrate Analog Output 2 for the 10:1 - 20:1 scale as noted above.
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Old 12-20-2007, 12:39 PM
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good luck getting the grounding right. Mine is crazy and can't seem to get it working without interference.
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Old 12-20-2007, 12:48 PM
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If you ground it at the same spot as the ECU is at the block and then properly heater cal and free-air call the sensor, you won't have any problems.... I've setup countless cars and never had an issue when wired properly. I've also helped a handful of people correct botched installs who claimed 'it would never work' and then did just fine after I fixed their grounds and re-cal'd the unit.


Here's a quick-n-dirty on how to recal the LC-1 with XD-16. It's the same without the XD-16 though. You just have to watch the LED instead of the digital display.

1. Power off.
2. Remove the sensor from the pipe and dangle in free air (exhaust free room!)
3. Unplug the sensor from the cable
4. Power On for 60 seconds (powering on for 60 seconds without a sensor connected tells it to heater and free air cal on the next power up)
5. Power off.
6. Plug the sensor into the cable, leave it in free air.
7. Power on.
8. Watch the XD-16 as it heats up, then heater cals, then free air cals. If you want, after that's done, use the CAL button to free air cal it yourself. I usually do for that warm and fuzzy feeling
9. Power off.
10. Put the sensor back in the pipe.
11. If your install is good and the unit/sensor are good, you're good to go. Power up and rock on...
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Old 12-20-2007, 01:05 PM
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Originally Posted by Saml01
1. No idea. Why does it matter?
The voltage value for 14.7 is the switchpoint voltage in EGO correction. If that is wrong EGO won't work right.
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Old 12-20-2007, 01:33 PM
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Originally Posted by cjernigan
The voltage value for 14.7 is the switchpoint voltage in EGO correction. If that is wrong EGO won't work right.
Doesnt megatune set that when you set it in the configurator?
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Old 12-20-2007, 02:07 PM
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Originally Posted by Saml01
Doesnt megatune set that when you set it in the configurator?
Not really - there's a couple different places you have to specify things. With the target voltage, this is so you could target some other air/fuel ratio. If you wanted it to target 16:1, you could.
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Old 12-20-2007, 04:41 PM
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Ok thanks, so I CAN connect the brown cable to the original WB cable (the plug next to the cam angle sensor)? Or do I put it directly on the MS?
What do I do with the yellow wire, nothing?

Thanks for the input
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Old 12-20-2007, 04:56 PM
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Originally Posted by Saml01
4. Could be either, yellow or brown just make sure you configure them properly. The MS will need 0v = 10,5v = 20. The LC1 DB gauge will need the factory settings of 0v = 7.35, 5v = 22.99.
Ok, so how do I configure MS for 0v=10 , 5v=20 and make the DB gauge show me the right AFR at the same time?

And would it be ok to wire the gauge to the hazard lights button?
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Old 12-20-2007, 04:59 PM
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Originally Posted by Saml01
3. If your car has a day time running light plug like my 97, you can tap into the White/black stripe wire at that plug.
Do I have that on my 90? I dont think so
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Old 12-20-2007, 05:50 PM
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Ok, sorry for the questions but Im hoping to get this done tonight.
I have the Db1 gauge. It has 4 wires and the manual is crap and doesnt say anything on how to wire it.
The blue wirre goes to the brown wire (output 2), this brown wire will also be connected to the stock O2 sensor plug, right?
The BLACK wire?????
Purple????
Red???

And where does the LC1's yellow wire go, (the 0v - 1v analog wire)?

If I can get this quesstions responded I wont bug anymore. And yes I DID a search
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Old 12-20-2007, 05:53 PM
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Originally Posted by 90turboMX5
Do I have that on my 90? I dont think so
No you don't. 90-93 and 94-97 DRL wiring is totally different.
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Old 12-20-2007, 06:19 PM
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Originally Posted by 90turboMX5
Ok, sorry for the questions but Im hoping to get this done tonight.
I have the Db1 gauge. It has 4 wires and the manual is crap and doesnt say anything on how to wire it.
The blue wirre goes to the brown wire (output 2), this brown wire will also be connected to the stock O2 sensor plug, right?
The BLACK wire?????
Purple????
Red???

And where does the LC1's yellow wire go, (the 0v - 1v analog wire)?

If I can get this quesstions responded I wont bug anymore. And yes I DID a search


black -ground
red - power
purple -dimming adjustment if desired.
blue- input from LC1 (brown)
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Old 12-20-2007, 06:24 PM
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Originally Posted by 90turboMX5
I have the Db1 gauge. It has 4 wires and the manual is crap and doesnt say anything on how to wire it.
I would suggest using both analog outputs of the LC1- one to drive the MS, one to drive the gauge. So scale both analog outputs for 0v = 10:1 and 5v = 20:1.

The manual for the DB gauge seems pretty straightforward to me. Red and Black are power and ground, blue is analog input, and purple is backlight.

Run the brown wire of the LC-1 (analog 2) to the blue signal input wire on the DB gauge.

Run the yellow wire of the LC-1 (analog 1) to the wideband input on the MS.

Run the grounds of the gauge and the LC-1 to the same point as the ground for the MS, preferably to the ground point on the head.

Take the power for the gauge and the LC-1 from the same point as the power to the MS.

Run the black wire (calibrate) from the LC-1 to a convenient place.

Connect the purple (backlight) wire from the gauge to the parking light wire somewhere in your car. Consult the factory wiring diagram for your year at http://www.madracki.com/miata/wiring.html Looks like the red-black wire should do it.
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Old 12-20-2007, 06:32 PM
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Originally Posted by Joe Perez
I would suggest using both analog outputs of the LC1- one to drive the MS, one to drive the gauge. So scale both analog outputs for 0v = 10:1 and 5v = 20:1. [/URL]

No, dont do this because your LC1 DB gauge will be completely off. It is designed to work with only the factory voltage output by the LC1. I learned this the hardway. If you want to emulate the narrow band, retain the gauge, and send a signal to the MS. You will have to setup the MS to work with the LC1 factory output put the gauge and MS on the brown wire, and send the yellow wire to the NB plug next to the cam sensor.
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Old 12-20-2007, 06:35 PM
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Originally Posted by Saml01
No, dont do this because your LC1 DB gauge will be completely off. It is designed to work with only the factory voltage output by the LC1.
Good call.

Ok then, leave the scaling of Analog 2 (brown wire) alone, and re-scale Analog 1 (yellow wire) to 0 = 10, 5 = 20.
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