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Screwy Lc-1 readings, Misfires then crash and burn.

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Old 03-28-2010, 02:21 PM
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Post Screwy Lc-1 readings, Misfires then crash and burn.

So I have been continuing to try to and get this MS install sorted out on my car. Some things are getting are working properly but I am having some serious little gremlins.

I was having serious noise in TunerStudio, my Lc-1 readings were jumping all over the place. I totally reinstalled the Lc-1 and ran fat 14g grounds right to where the ECU is grounded and that solved the noise issues.

On cold starts the readings are correct and match the gauge. After I reach running temp things start to go crazy. The Lc-1 readings in TunerStudio stop responding, and matching with the gauge going almost static. The readings will say 11-13afr when my gauge is reading correctly.

After my car is at running temp, it starts getting all kinds of misfires under boost. These misfires will sometimes show up as resets, as secL will reset. Sometimes these misfires will also cause Tunerstudio to crash. This will happen from about 4-7 psi.

I have done hours of searching the internet, hours! I cant seem to find any info regarding this. If you guys have any ideas or feedback, it would make my day!

I have attached a log of it warming up.
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COLDSTART.msl (542.3 KB, 110 views)
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Old 03-28-2010, 08:56 PM
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Misfires can cause all sorts of nasty electrical noise. I would not be suprised if the misfires were the cause of your problems and the resets are the symptoms.

How fresh are your secondary ignition parts (plugs/wires)? What's your plug gap?
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Old 03-28-2010, 09:25 PM
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You probably already have checked it, but it's worth a shot...
Check your boost threshold. My "misfires" had me puzzled for a day or so until I remembered about that setting...
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Old 03-29-2010, 01:25 AM
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Ben, I did recently replace my plugs and wires around 10k miles ago. Im running some regular NGK plugs and the wires are some Autozone oem style. If I can remember I gapped them to 36 I'll check tomorrow. Is there a magic number to gap them at?

Flipt, I did set my boost threshold way high just incase. When I first got it put together it was sat at like 2 though and it did cut out when I hit that, so its working.
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Old 03-29-2010, 01:40 AM
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I gapped mine to 25
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Old 03-29-2010, 04:21 AM
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.036" might be too much gap. Try .025-.030". I'd also be suspicious of 10k mile old cheap plug wires.
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Originally Posted by concealer404
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Old 03-29-2010, 08:05 PM
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The plugs were gapped at .04! I gapped them to .025 and replaced the shitty wires that broke when I took them off. No more misses or resets as of now and runs great!
You guys are awesome thanks so much!!

As for this LC-1 crap I am going swap to the other analog output and see if I can get a consistent reading.
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Old 03-29-2010, 08:16 PM
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Good to hear man.

I fought the same issues, got fed up with it, and went the COPS route. I run .040" gaps now, and nary a hiccup.
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Old 03-30-2010, 12:16 PM
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Hell yeah.

I'm definitely thinking about doing a COPS setup in the near future. Or atleast getting some real spark plug wires ha.
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