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Old 03-15-2009, 01:32 AM   #1
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Default Technical Question: Trouble with LC-1 and MSPnP

Hello,
I hope the thread name is better this time.

I am trying to troubleshoot my LC-1 that is connected to my MSpnp with a brown analog #2 wire through stock plug next to CAS, the lc-1 gets power from a plug that is used for connecting the timing light so its not hot when cranking. All the negative wires are connected together into one plug and grounded to the bolt on the back of the head. There are two ground bolts there so i am not sure which i have to use, so the one in the picture is NOTthe one i connected it to. The one i connected the ground to is the one that is lower and a little closer to the passenger side.



The Problem: Everything was running fine for a few days, car idles great and drove well. But later the cars started to cut off. When i was driving in 3 gear pretty slow the revs momentarily go down from like 3k to 2k and the car stuttered and was back to normal in split second time. This happened several times.,

Something similar happens when the car is idling. Everything would be fine and then suddenly the afr would go from 15 to 19 the car would stutter and go back again to normal.

It almost feels like its a bad ground.

Questions:
1. Is my LC-1 wired right?
2. Where is the best place to wire positive LC-1 wire so its hot when cranking. Please tell me the exact wire. I am really terrible with wiring. I know there is a fuse box but i have no idea which wire to cut into.
3. Which ground is the ECU ground? the one in the picture above or the other one next to it.
4. I want to set up a gauge that came with LC-1. I tried to reprogram Analog#1 to show wideband reading just like Analog#2, it did show the same reading that LogWorks did on the screen of my PC but made the car run rough at idle and showed very lean reading like 19. After i unplugged the gauge and started the car again it ran fine.

I did read both MSPnP and LC-1 manuals multiple times and i did reset the LC-1 and performed Free Air calibration.

Please help me out here i spent all night trying to figure out this problem and getting hopeless.

Thanks
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Old 03-15-2009, 02:08 AM   #2
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Picture can speak a thousand words so here is how i have stuff set up.
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Which one is the right one for the ECU ground, #1 or #2?

The second picture is where i got the +12V for the LC-1 Controller.
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Old 03-15-2009, 02:39 AM   #3
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let me make this real simple, becuase I've screwed it up a few times.

solder every computer / lc-1 wire together on one ring connector.
Get power from a source that is hot when cranking.

/problems
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Old 03-15-2009, 02:44 AM   #4
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Quote:
Originally Posted by hustler View Post
let me make this real simple, becuase I've screwed it up a few times.

solder every computer / lc-1 wire together on one ring connector.
Get power from a source that is hot when cranking.

/problems

I get that. The problem is that i dont know which wire is hot when cranking. Please tell me what wire is hot when cranking. And what ground is ECU ground.
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Old 03-15-2009, 11:40 AM   #5
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Quote:
Originally Posted by Rushin View Post
I get that. The problem is that i dont know which wire is hot when cranking. Please tell me what wire is hot when cranking. And what ground is ECU ground.
Solder them all together on the back of the intake plenum (on my 1.6) and it doesn't matter which one you get. I don't know which is hot either. Do your lights stay on when they crank? Put an "add a circuit" there. That's what i did, and I had a "Dallas-9" drive down to "see me" last night.
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Old 03-15-2009, 07:03 PM   #6
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I think you mean hot when ignition is in the ON position, not the START position. The sensor takes like 10 seconds to heat up anyway, having it hooked to IGN+Start doesn't matter, finding a good ignition power source is whats important.


I tied all the grounds together, soldered on a ring terminal. I ran a braided strap from the factory engine ground to a lug where all the MS, EDIS, and LC1 grounds go to prevent ground loops and stuff.
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