MartinezA92

iTrader: (4)

A monkey is better at wiring and understanding this stuff then I am.

I've got an LC1 and a gauge sitting in a box in front of me. For a power source, what did some people here use? I know its something that maintains a steady voltage during cranking. Basically, I'm gonna copy what anyone here has. And for grounding, where exactly am I supposed to ground this thing? From what I've read it seems like I'd ground it on the stock ECU but I don't wanna burn something up and start making a smoky mess.
I'm not hooking the lc1 up to the stock ecu, I'm probably just going to get a second bung welded and have the ECU read the stock o2. Unless someone says otherwise that this is a really bad idea...

Joe Perez

iTrader: (8)

If you're not connecting the analog output to an aftermarket ECU, you can ground the unit nearly anywhere. Just run a wire to the back of the head.

As to power, some folks have had trouble with sources that are hot during cranking, as the LC1 seems to get irritated when its supply voltage drops too low. Even at the battery, you're gonna be at maybe 10v during cranking.

Mine is powered through a common automotive relay that is sourced from battery through an inline fuse. The relay coil is driven by the wire which feeds the radio, which is hot in ACC and RUN, but not in crank.

MartinezA92

iTrader: (4)

You had me until you said this. Do I have to go out and buy a relay and a "inline" fuse? (I'm going to assume thats just a fuse in the middle of the wire) Or do you mean you used a relay that was already in the car?

Joe Perez

iTrader: (8)

I used a new relay (well, an old one that I had lying around, but new to the car) and ran a new wire direct from the battery. This is the reason that I installed an inline fuse.

I did this only because the wiring in and under my dash is starting to get out of hand, and I didn't want to burden any of the already overtaxed stock circuits with yet another huge resistive load. I installed the relay inside the center console armrest thingy, just aft of the cupholder. This space was chosen primarily since that was the last few cubic inches of the interior that wasn't already jam-packed with electronics.

If you're not already straining your stock radio circuit with a bunch of extra doo-dads like the power supplies for a laptop, a GPS navigator and a CB radio, then you can probably just source switched +12 from that line and be done with it. No extra fuses or relays required. On your '92, this will be a blue wire with a black stripe.

MartinezA92

iTrader: (4)

My radio (and I'm assuming others) turns off during cranking, someone else had told me it would work, but the radio turning off is what threw me off...

This question will probably make me look like an idiot, but how would I steal power from this wire and still have my radio work? As in, what would I need to have 2 things running off of one wire?
And just to make sure, this blue wire with the black stripe is directly behind the radio right? My radio pulls out fairly easily, that's why I ask.

Joe Perez

iTrader: (8)

Yeah, that's the point. The folks who have complained about the LC1 losing its mind seem generally to have the unit wired to a lead that is hot during cranking. Even if it's coming directly from the battery, you're going to be in the 9-10v range during that time, and though it's only speculation, this may be what's throwing it off. Mine has been rock-solid since install, and I attribute that to both proper grounding and a stable supply.



One of these:





Yep. It's at the upper-right (or upper-left) corner of the connector that plugs into the radio, depending upon your frame of reference.

MartinezA92

iTrader: (4)

Are those like butt connectors for crimping but 3 wires would meet in the middle instead of 2?

Joe Perez

iTrader: (8)

The darker piece on the top is a vampire tap. It's a slotted piece of metal inside a hinged plastic case. You place it over the wire, fold it over, and crimp it down with a plier. The wide is forced up through the slot and makes contact with the metal tab just like on a punch block.

Then, you terminate the new wire with an insulated male disconnect (the bottom part) and you can then plug it into the vampire tap.

MartinezA92

iTrader: (4)

I wiki'd what a punch block was, because I had no idea what one was. So you don't have to remove any insulation off the wire, just have the vampire tap bite into it?

Joe Perez

iTrader: (8)

Correct. That's the whole point of the vampire tap in the first place- you don't have to do any prep work on the target wire. Just slide it over and crimp it down. The insulation helps hold it in place.

Now, to be clear, from an idealist's perspective I'm supposed to hate these things. Anything that isn't either a soldered connection or a nice two-level crimp with foldover and strain relief is considered to be junk in my line of work. OTOH, the pragmatist in me realizes that I've probably got several dozen of these connections in my car (and thousands more in the field) and they haven't resulted in any loss of life, or even loss of audio.

Go forth, and splice!

mx5tunerchallenge

There is a blue connector where you attach the timing light in the engine bay. It is near the drivers front headlight. Wire the power into that with a fuse in between.

Scotty15

I just put an LC1 in my '95. My car does not have power windows, and I was happy to find the unused connector sitting under the center console. It has a nice fat switched hot feed (black wire w/white stripe). I used this to power the LC1 and a G2 gauge. Works great.

BTW, the G2 gauge does not necessarily need a constant 12V feed. That is only to zero the gauge after you turn off the ignition. Just wire both hot feeds to the same switched 12v source. If you are really lazy you could tap the light here also, so you would only have to hook up 3 wires.

MartinezA92

iTrader: (4)

So, basically I could vampire tap the same wire (black wire w/ white stripe) for the gauge AND the LC1?
Laziness has gotten the best of me and I am finally going to try this on Friday.

ZX-Tex

iTrader: (15)

Last week I just did exactly the same thing in a '94. I tapped into the power for the power windows for both the gauge and the LC-1. I grounded the LC-1 AND the gauge to the same ground lug, and attached the lug to one of the shifter boot bolts. Works great.

I am not running an LC-1 output to an ECU so this grounding scheme is OK IMO. If you are running an analog output to an ECU, it is important that the gauge, ECU, and LC-1 all use the same ground.

Screw vampire taps. Use solder and shrinkwrap (or at least use good quality 3M electrical tape) for all the connections. A flaky connection could give you errors in your AFR readings. Not on or off, but on and reading/displaying false AFRs.

Scotty15

I twisted the LC1 +12V, Gauge +12V constant, Gauge +12V switched together and crimped on a male spade connector. Then just plug it in.

MX_Eva

I've followed the instructions on the LC-1 I AM using it with my MS once the MS is done, I've also pulled power from the window switch, though only because my radio was all sorts of dumb (thanks Previous owner).

However, I can't seem to get the "ready" Light to come on solid, I've done a good drive gotten the whole car up to operating temp and the light still blinks. Do I have a bad sensor? If so obviously I should contact the seller and get them to send me a new sensor or WTF? It's a tad concerning to have a car untuned and rolling into 4 - 5 psi on stock injectors and I'd at least like some warning of things being amiss.

Scotty15

The LC1 can be a real pain to get set up.

Where did you put the sensor?

Can you get the unit to talk to your laptop?

MX_Eva

I haven't tested it to a laptop yet. It's located on my down pipe after the turbo elbow about an inch from the flanges.

I'll test the laptop deal though seems easy enough.

gospeed81

iTrader: (51)

If I'm understanding your placement that may be too close for the LC-1.

triple88a

iTrader: (2)

wait which wire is the steady voltage wire? i just got mine and in the instructions it only says switched 12v power source, they never mention continuous 12 volts.

Mine has 6 wires..

red blue white yellow brown and black.

red is to switched wire
blue and white are ground
yellow and brown are analog out 1 and 2
black is calibration wire that has a switch and an led that connects it to ground.

then my gauge has 4 wires (gauge is innovate DB)
red goes to a switched 12v (ignition switched)
black goes to ground along with the blue and white from the LC1
the white one goes to the brown one from the LC1
then the yellow goes towards the headlights power wire for a dimmer.