hermyboy3000

I'm losing my mind over here. So, I thought I had an exhaust leak, because I was missing two of the nuts that hold the front exhaust pipe to the header. I thought fixing that would get rid of it. It didn't, it just shifted when the pining/tapping happens (used to happen in between 1400 & 2400rpm) What could this be?

I hope its not a spun bearing. Wouldn't I hear that pinging/tapping sound throughout if it were a spun bearing?

A mechanic buddy of mine thought it was piston slap, is he right? How do you diagnose piston-slap? He didn't thing the bearing was spun because he also noticed that the sound occurred at those certain RPM ranges.

I've read a few people on here describe the sound as a "card in the spokes" and mine does sound like that but definitely more metallic.

Oh yeah, tried higher octane fuel, BG44k, ZMAX, heavier weight oil (not straight weight, yet) none of that worked either.

I'd love to know what you think. Thanks in advance!

coryc85

Read this guy's problem and listen to the sound clip in post #7 here: https://www.yotatech.com/forums/f116...cement-192784/

My rod knock sounded exactly like that guy's. Number 1 rod bearing was toast, https://www.yotatech.com/f191/coryc8.../#post51346635

hermyboy3000

cory, I couldn't get that guy's audio to play, so I don't what his tapping sounded like.

A buddy of mine told me that If I had a shot rod bearing, I would see metal filings in my oil filter. I did an oil change yesterday and I dumped out the oil in the filter onto a clean shop rag and saw no filings, I did see ever-so-tiny glints of what looked like metal, and when I mean tiny, they were very hard to see. Anyway, this made me a little concerned, so, I took a hacksaw to the old filter to see if there was any metal filings/shavings. After hacking it open and looking at the paper filter inside, there was nothing. So was my buddy wrong about the filings in the filter or do I not have a spun bearing?

I used a stethoscope to try to locate the sound, I heard nothing out of the ordinary in the block. Granted, I'm really sure how to use it. I placed the scope on the sides of the heads, sides of the block by the oil pan, the bell housing and on the intake manifold. Is this the right procedure to find that sound?

hermyboy3000

BTW, what I meant to say, in my last post, is that I'm not really sure how to diagnose a car by listening to it. However, I used the stethoscope again to listen around. I focused around the top of the heads, around the valve cover, and I listened to the injectors.

Here's what I discovered, all but one of the injectors had a steady tapping sound that changed with engine RPM. The injector in question (cylinder 2) sounded like a jack-hammer in comparison to the others, but it only made this sound when load was applied. When there was no load it still sounded different but the tapping was consistent to the others.

As I poked around with the scope a bit more around cylinder 2, the sound couldn't be heard at the valve cover when I listened up against the head just under the valve cover at cylinder 2, I could hear the jack-hammering but very faint. When I listened at the exhaust manifold I could hear the jack hammer sound clearly, but nowhere near as loud as I did at the top by the injector. When I listened to the block at cylinder 2, I heard nothing.

What makes me scratch my head is that when I'm not using the stethoscope the sound definitely comes from somewhere lower in the engine, but I can't find that tapping sound anywhere under the engine with the stethoscope.

STUMPED, STUMPED any suggestions?

bigdaddy87547

I believe this is what my 4runner is doing also. The best way for me to describe is as a jar of spoons rattling. (i heard someone else say that on here). Mine does it in the rpm ranges you said also. I've been able to hit my gas and brake pedal at the same time coming to a stop sign, and keep the gas pedal deppressed and hear the noise. I have not for the life of me been able to diagnose the sound. It drives me crazy because my truck is the truck of many different sounds. (exhaust, intake,rattling,air flow meter makes noise, and music).