so i have been having a problem with my 93 3000gt vr4 car would run great till one day car started knocking the sound looked like it came under the intake manifold every time a rev it it will start knocking its not that loud but it knocks i have been searching and they have told me that it may be a bad rod bearing i have also heard that it can also be the knock senosor i dont know if that sensor may cause my engine to also knock i have already taken off my oil pan and have inspected the bearngs i can see the cooper color on them already i dont know if that is normal or if thats the case to what is making my car kock please some one help me out
The copper showing on the bearings at the very least shows they need replacing, but since you were knocking already replacing the bearings probably will not fix the problem. Your crank and rods will need to be reconditioned/resized.
i have inspected the crank and everything looks fine is it possible that maybe the bearings are just worn out seens i have 163,000 miles one my car i have been searching around and i belive that knock sensor does knock it has to do with the timing and engine vibration correct me if im wrong are u sure about that can it also be some misfire or something what else cause engine to knock at idle
the knock sensor is a microphone that communicates noise to the engine computer. It is designed to detect detonation and allow the ecu to reduce ignition timing and enrichen the mixture to reduce the detonation. It doesn't produce any sound on its own and you could remove it completely and the engine won't make noise.
It is possible the bearings are just worn, but usually when they are worn to the point of an audible noise it means that something will be out of round. The noise is the rod colliding at high speed against the crank shaft journals. Usually this will push a rod out of round.
so there would need to be a broken rod bearing in there right i have checked the crank and it looks smooth and free from scratches what would you recomend some mechanic told me it didnt sound like a bearing he says that usually when that happens the sound comes from the bottom of the engine and that the sound can be heard even if you dont rev it in my case it sounds like its comming from the top of my engine and it only sounds when i rev it just a little it sounds like something is lose would you happen to know what size are the rod bearings supposed to be are they suppose to be 0.25mm or what size
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