I have been rebuilding my wrx in my spare time and i have been having issues. I had a dead cylinder and i out new rings and pistons and bearings in. After i put the engine back in i had fixed the cylinder that was dead but now i have a knocking sound. It sounds like a light tap on the passenger side front of the engine. its enough to get my attention. When i unplug the coil pack for that cylinder the noise stops. So today i took off the valve cover and pulled the engine. I was hoping that i just had a keeper that was out or something but they were all okay. I am at a loss of ideas. I noticed today that i had a cracked spark plug in that cylinder but that doesn't explain the knocking sound. any help would be much appreciated.
I'm not even close to being an expert on this but I would try:
Put a fresh plug in, reconnect the coil pack, but disconnect the crank position sensor, and pull the fuel pump fuse. Turn the engine over with no spark/fuel and see if you still hear the noise. Also, pull the plug again afterward and see if it has been re-cracked.
A light tapping noise sounds like an injector or maybe a messed up cam or something... What is throwing me for a loop is that disconnecting the coil pack fixes it temporarily. Have you let the engine warm up all the way? Does the sound change with RPM? Maybe try posting a recording of the sound?
It's very odd. I let it warm all the way up and when I pull the plug on it the rpms do not change the knock just goes away. So I am not getting much out of that cylinder. I am afraid I may have to take it apart again and start all over. My only thought is that a rod may be on backwards or something I have no idea. I'd like to know if anyone has had this problem before
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Subaru WRX Forum
329.6K posts
38.3K members
Since 2002
We're a forum community dedicated to the Subaru WRX. Come join the discussion on performance modifications, accessories, turbo upgrades, maintenance and more!