LSx misfire issue, come inside

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Nov 6, 2007 | 01:14 PM

icicleboy

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LSx misfire issue, come inside

Hey all,

so we've got this LS4(FWD) turbo that is making great horsepower, probably in the mid 400's at the wheel through an auto trans. Our only issue is a random misfire which doesn't happen ALL the time, but happens often. Generally happens at 5000rpm or so (4900ish). So far, I've increased the dwell bit by bit up to 6ms, and have installed fresh autolite 104's @ 0.025 to see if it would cure the issue. Still has the issue. I can't imagine that these coils are any different then any other lsx, and am just not sure what else could be the issue at this point. Car runs about 10psi, and utilizes alky injection (50/50 WW fluid).

Any input or suggestions would be greatly appreciated.

Nov 6, 2007 | 01:32 PM

brandon619

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What kind of plug wires are you running? I just had the same problem on my Procharged Z06. I had two problems when I removed the headers and cracked a couple of plugs. Then replaced them and still had a slight miss up top like you. Then I replace my 8mm MSD wires with some 10mm Taylors and problem was fixed.

Nov 6, 2007 | 02:24 PM

icicleboy

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Quote:

Originally Posted by brandon619

Still running stock wires... I was hoping that stock wires would suffice though?

Nov 6, 2007 | 05:26 PM

brandon619

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From: San Diego

Quote:

Originally Posted by icicleboy

Still running stock wires... I was hoping that stock wires would suffice though?

I would change those stock wires.

Nov 6, 2007 | 07:15 PM

icicleboy

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hey guys,

thanks for the responses. Are you suggesting to change the stock wires for something aftermarket? or just change for fresh stockers? I'm used to the GM DIS 2 plug/coil system that can actually support well over 500whp on stock wires/coils. Are these individual coils/wires not as strong? Are forced induction people on this board all running aftermarket wires with over 400whp?

Thanks again

Nov 6, 2007 | 07:22 PM

LS1curious

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I can;t see either the wire or the plug being the problem. Turn up that dwell to around 10-15ms. I have seen some of the coils be sensitive to problems with dwell. the other possibaility is Knock Retard.

Quote:

Originally Posted by icicleboy

Nov 6, 2007 | 08:21 PM

icicleboy

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All the data I've read has said that the lsx coils won't stand up to much more then 6ms without overheating and dying very fast. Stock was about 3mS. There is no KR. none ever.

Thanks again