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Crackling exhaust noise on start up


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Every since I went stage 2, or it may have been when I replaced cylinder 2 due to a broken ringland, I've been getting a crackling noise about 10 sec after I start it on a cold engine. It does it for about 15 seconds or so and stops. I'm not sure if it's the exhaust expanding, or if it's related to the cylinder job. I've got MadDad UEL headers/up pipe combo, a CNT catted DP and a Magnaflow cat-back. It's flashed to a stage 2 Cobb tune. I need a protune which I'm planning on soon. Any input/like situations?

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the secondary air pumps runs for 10-15 seconds during cold starts, the engine can sometimes run rough and loud for that period and then smooth out shortly after that...

 

I was going to say that. But that's a different noise then what he's describing.

 

Nice try...;)

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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The only other thing I notice and it's been doing it since cylinder 2 was replaced, is I get a pretty faint knock occasionally. It's completely inconsistent and it will be up to 30 sec to a min in between. It's a light vibration and a faint knock after its been idling. It sort of skips. My father listened to it and just thought it was tune up issues.

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Okay. Who reassembled the engine and did anyone check valve lash? Over time you lash will be smaller and smaller and if you install new valves, they need to match the rest or else you'll have issues. Tight valves can tick tick and tap tap and thats not an issue but if you log roughness in that cylinder and find counts of misfire, the lash isnt appropriate. So figure you have new valves, perhaps too much fuel is entering and detonating due to improper intake and exhaust lash. This could relate to your popping sounds.
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Yeah I'll try and get all that up this weekend. I've never data logged with the accessport so I'll have to figure it out. Put It to use before I get rid of it. Gonna take the legacy to brentuning once I get some extra money

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Hm Yeah I'm really not that far, I'm in Dover. I am pretty curious to find out what the deal is. If I don't get approved for some OT I'd probably go for a drive. Sucks I wouldn't be able to compare with a cold start but I'll take a video with my phone tomorrow morning.

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  • 10 months later...

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