Odd Popping Sound After Catch Can Install

[shibles]

So I just finished fabricating a mounting plate for a Mishimoto catch can and installed it in my car. Ever since then I've started noticing a popping sound when the engine is running on idle while sitting in the cabin. It's more pronounced and louder when the weight is transferred forward (on a hill or braking). It happens regardless if the climate control is on or not. Haven't noticed a difference in starting, running, revving, or hard pulls on the engine (although I've been babying it a bit since I first noticed the sound). I also haven't gotten a chance to hook the Ktuner up yet to look for any unusual numbers.

I'm running stage 2 tune but haven't put ethanol in for a good few hundred miles, I'll actually be getting rid of the system and going back to stage 1 tune soon.

I don't see how the catch can could cause the sound. It's at the same frequency as the engine, and I've tried listening for it in the engine bay but it's drowned out by the cacophony that is our fuel injectors. I'd say the sound is more towards the rear of the engine though. Any ideas on what it could be?

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[SDAlexander8]

So you needed to fabricate your own mounting plate because the flex fuel kit get in the way of the plate Mishimoto provides?

I would take the can off and blow into the catch can and see if it makes the sound. I get a bit of a wooshy rattle sound from mine under heavy acceleration, but no popping noises. Sounds like the sound a vape thingy makes when you suck on it hard.

 

[shibles]

Hmm, not quite the noise I got but I'll give it a try.

I had to make my own because I didn't order the specific catch can for my car, I got their universal one and rubber hosing. I work in a machine shop and had some scrap stainless steel sitting around so I figured I'd save the ~$40 on that. The flex fuel kit I built myself and didn't need a mounting plate for it at that part of the engine.

 

[shibles]

I don't think that's what it is. Putting my ear next to the catch can and in the engine bay I don't hear the sound coming from the catch can. I'll try putting the OE PCV line back on for a sec tomorrow to see if that stops it.

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