But if a weird one. When revving up and coming off the power I get what sounds like back firing coming from under the right side rocker cover along with rattly mechanical noises. It's an EJ25 SOHC 2001 engine. I have pulled the cam out in the past. Could it be possible the valves are sticking open allowing burning gases either way, and the tappets became out of adjustment? Just asking for some pointers on what a possible cause could be and if there is anything you suggest to look for when I start stripping it down. It doesn't always do it and pouring upper cylinder head lubricant down the throat seem to help a little. The sound isn't coming out the exhaust (only have the y pipe is on the engine at the moment) and it isn't coming out the throat either. Sound only seems to come from the rocker cover...

all I have for this are wild guesses;

 

double check cam/crank timing? maybe skipped a tooth

 

vacuum gauge testing night be a good, cheap place to start - online charts will show you what it can help diagnose.

 

there's also a youtube video showing how to inspect for 'dropped' valve guides. they can even shift around leading to intermittent symptoms.

 

take the oil fill cap off and feel for a pulse there when the sound happens. maybe something odd like a broken ring land causing too much crankcase pressure?

 

otherwise???? something loose in side the cam cover? broken valve spring?

 

 

hope someone else has some ideas for you.

Edited February 15, 20179 yr by 1 Lucky Texan

Skipped timing would likely give you a cam/crank correlation code or something similar or would have a slightly rough idle.

 

Issue sounds mechanical from the description. I would start by pulling off the cover. Be mindful of falling bits so you don't lose them just in case.

Exhaust gasket blown out or the y-pipe cracked maybe.

Those heat shields like to rattle around a lot. Tap on those and see if they make a similar noise.

Hard to tell what's really making noise if there's nothing attached after the y-pipe.

It's not an exhaust gasket issue as I've felt around the gasket and there are no leaks and I'm certain the noise is not coming from that area but up around the cover.

 

It's not can timing as I've just put the belt back on and all is set perfectly. The idle is good.

 

Thanks for the other hints, I'll investigate when I can get back in the garage.

Found the cause of the noise but still unsure how that damage on the rockers was caused. The two short bolts in the intake rocker shaft came out and were loose in the cam tower. There is no damage to either the rocker cover or the bolts them selves.

Edited February 17, 20179 yr by Phizinza