I'm looking to install a lc-1 on my 91 miata running mspnp tomorrow. I am planning to run the main power line to the alternator with a 5 amp fuse inline, ground to the block where I ran a fresh ecu ground to. My specific question is where to hook the turn on lead. From what I understand it needs to be a source that has +12 volts while cranking. Instead of prodding around with a meter, I imagine someone on here already knows a good source to tap. Thanks in advance.
-
Jan. 2, 2012 4:50 p.m. bigbrainonbrad Reader
-
Jan. 2, 2012 5:24 p.m. unevolved Dork
I've run electronic hourmeters off of the ignition coil (+), but I'd imagine that might be too noisy for the finicky Innovate stuff.
-
Jan. 2, 2012 5:47 p.m. Keith SuperDork
If the car doesn't have ABS, there's a hot connector where the fuse would go in the box under the hood.
Never mind, I just realized that's b+ - at least, I'm pretty sure it is. You need switched. is the blue connector by the drivers headlight hot while cranking?
-
Jan. 2, 2012 6:38 p.m. chaparral Reader
Miata headlights shut off during cranking. Maybe the wire to the relay that controls the lights-off-during-cranking function?
I don't think there's anywhere on the car that gets regulated 12v during cranking with the possible exception of the factory ECU power input. You'll get switched B+ from the starter solenoid wire during cranking - will that do.
-
Jan. 2, 2012 7:19 p.m. peter Reader
For my LC-1, I bought a O2 sensor pigtail from FM salvage and used the power/ground connectors from that. I didn't have great results (the contraption stopped working right), so you might ask the smarter folks around here if that wire can provide the current necessary to run the LC-1, but that was the solution I came up with. Also provides an easy way to send the WBO2 sensor signal back towards the cockpit (if your wiring harness at the CPU is so arranged)
-
Jan. 2, 2012 7:25 p.m. Keith SuperDork
The logic for circuits that lose power during cranking is in the ignition switch, not a relay. I'll check a diagram at work tomorrow.
-
Jan. 2, 2012 8:19 p.m. 92CelicaHalfTrac SuperDork
Tell me about why the lc-1 needs 12v while cranking? It's not reading anything at that point, it's still in warm up mode.
I'm pretty sure i just powered mine off the cig lighter circuit. It doesn't take much power at all. I really don't think it matters if it's interrupted in cranking. Mine is.
-
Jan. 2, 2012 8:30 p.m. Woody SuperDork
Keith wrote:
You need switched. is the blue connector by the drivers headlight hot while cranking?
The blue plug is hot anytime that the ignition is on.
-
Jan. 2, 2012 8:40 p.m. bigbrainonbrad Reader
On a related note, I want to install under the hood for ease of connections and what not. Is this something that should be inside the cabin? If so, where is a good place to get the O2 sensor and wire through the body?
-
Jan. 2, 2012 8:53 p.m. 92CelicaHalfTrac SuperDork
bigbrainonbrad wrote:
On a related note, I want to install under the hood for ease of connections and what not. Is this something that should be inside the cabin? If so, where is a good place to get the O2 sensor and wire through the body?
The controller is made to stay under the hood. It's fine.
-
March 15, 2012 12:15 p.m. EvanB UltraDork
Did you ever find a wire to tap for +12v while cranking? I'm working on the wiring for my MTX-L and would like to have it on while cranking so it is working after it starts rather than taking 20-30seconds to start reading.
