metalhead8711

Hello everyone. I'm working on a 1989 camaro RS 305 with a TBI. Ever since we rebuilt the engine because the rings fried as I just got the car with a hidden problem. Over the last few months, the engine makes a really distinguishable knocking or tapping sounds. I've taken it to a couple of mechanics and they insisted that the problem may lie in the valve or hydraulic lifters but when they used a stethoscope, they were unable to find the source of the noise. I left out a detail that the car is probably missing a knock sensor. I say probably because since I've owned the car I did not see a knock sensor when we removed the engine and the area on the block had a bolt when we got it back from the machine shop. but there is a wire harness for the knock sensor, but I was not getting a check engine light for months until I took out the car to the freeway and after some sustained high speed driving I got codes 23 and 32. But the codes are recent but the noise goes back months. Would adding the knock sensor fix the issue or is there something more sinister? I've since replaced the egr and egr solenoid plus the o2 sensor because of a raw fuel smell but the smell is still there and the tip of the o2 sensor was ash whit . I'm assuming from the rebuild? Any suggestions would be very appreciated. Thank you.

GeneralDisorder

iTrader: (1)

Knock sensor is for detecting detonation, not mechanical noises. If the engine has tapping and knocking noises at idle (engines are basically incapable of detonating under low load conditions), etc, then you should heed the warnings and recommendations of the mechanics that you have taken it to. Sounds like you have a bad rebuild or valve train adjustment problems. You should start with an oil filter cut to check for metal, etc.

GD

metalhead8711

when I did the oil change last month the oil from the filter was very pearlescent. Shiny and glittery. But the noise doesnt seem to come from the pistons or crank. It's very top end where its loud. One of the mechanics after a valve adjustment and the sound didnt go away mentioned the possibility of a lifter not charging or taking oil? I should also mention that the frequency of the tapping matches the engine rpm but the sound seems to disappear at high speeds but I dont seem to notice the sound then. Sometimes on start up the sound is not there unless I give it a little gas then the sound emerges and stays there. It's weird.

GeneralDisorder

iTrader: (1)

Pearlescence in the oil could be metal flake, or it could also be carbon from blow-by, etc. Best to use a filter cutter to check for metal in the filter.

You can pull the valve covers and run the engine to check for oil getting through all the pushrods.

Also should check for any spongy lifters.

GD