Sr20 misfire help

Thread in 'Technical Questions' started by Srs_721, May 18, 2015.

  1. Srs_721

    Srs_721 Member

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    Hi everyone,
    Got a odd misfire with my s14 that im hoping someones experienced before and can help me.

    If i start the car from stone cold it runs lovely and smooth then as it starts to warm up it will start missing every few seconds.
    When its hot after a good blast it gets worse and almost stalls but runs smooth again for a few seconds then misfires again.

    Its very irregular and annoying as some times it runs really well with only the odd stutter. Even weirder is that it doesn't seem down on power and go's very well with only slight jolting at low revs.

    Attempted to get a little video of it


    Thats what it does on idle sometimes worse with stalling, hold the revs at about 2.5k it becomes a fast more regular miss then about 3k plus is smooth as anything.

    Its allways been there since ive had the car but its really fucking annoying now!

    Spec is usual stage 1a stuff but standard ecu, running solid 12psi via hks actuator.
    Compression test came back good, pretty sure there is no boost leaks after fixing a leaky idle valve the other day.
    Tried a set of coilpacks and seemed better but back to its old ways, got a spare loom i can try but cant see that being the issue.
    Plugs are copper ngks with correct gap few months old.
    Im thinking possibly the coilpack loom earth or the ignition amp?

    Any advice would be greatly appreciated [emoji106]
     
    #1 Srs_721, May 18, 2015
    Last edited by a moderator: Mar 6, 2017
  2. Tommoore99

    Tommoore99 Member

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    I'm no expert so don't go taking this for granted but s friend of mine had a similar issue on a ca, ran fine when cold and when it got hot the ignition leads started earthing on the rocker cover and created a misfire

    I'm probably tottaly wrong?

    Are you running a plug cover? Maybe take it off and let the heat escape a bit?

    I'm probably wrong but thought it was worth a shout
     
  3. Leno

    Leno Member

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    Sounds dumb I know but have you tried plugs? Easiest stuff first an all..
     

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