Using a Piezo sensor to identify a noisey valve.

Wightscope wrote: I don't have a clue what's making the noise!

Lol! That makes about 5 of us, in total. I've been collaborating with others, as well as this thread. I just posted it to a diagnostic group on Facebook. We'll see what some of those guys think.

Just a thought, am I right in thinking this engine is chain driven with VVT ?
Wondering if there is a missing tooth or something in the VVT mechanism causing the noise?
You did mention it was missing a lot of oil and I assume it has hydraulic chain tensioners...

Chad wrote: We'll see what some of those guys think.

You will. It's a private group :silly:

I think #2 intake valve can be ruled out. Noise appears to be happening before it opens. Don't see any way of telling which of the other 3 it is from the current waveforms though. Maybe a throttle snap or power braking would reveal a breathing problem??



Found this. Doesn't look like the noise could be caused by balance shaft or oil pump.

www.engineprofessional.com/TB/TB032816-1.pdf

BTW is this just for fun or are you still trying to diag it?

Matt T wrote:

Chad wrote: We'll see what some of those guys think.

You will. It's a private group

Would you like an invite?

is this just for fun or are you still trying to diag it?

Just for fun. :silly:

It turned out to be #2 rod bearing (#2 and#3 are companion cyliinders). Sitting on the ground, I would have bet money that the noise was in the UPPER end. I would have lost. When I, finally, got it into a bay with a lift, It was clear that it was LOWER end. I pulled the oil pan:


and removed the oil pump.
Video


For those that are thinking it, I will go ahead and say it. Old-school methods would have diagnosed this in about 15 min, or less. But, I would not have had NEAR as much fun.?

It was certainly interesting, and it was a good opportunity to brush up on in cylinder waveforms.

So the No1 low compression was a red herring - but still there.

What old school method would you have used for this other than perhaps a stethoscope might have nailed it bottom vs top then get the spanners out!

With that much play in the rod lower end, that piston may have been contacting the cylinder head. A borescope inspection in the cylinder may have exposed a clue in the piston carbon deposits being "modified" by the contact.