Okay guys. So I'm completely out of ideas. I was just doing a standard timing belt change with the pulleys. Everything is going fine, all the timing marks are right on, except the belt is pretty tight. So we put it all back together, drive it around, everything is great.
Then, after it's all warmed up, it starts knocking at around 3k, so I limp it home. tear it all apart, and notice that the tensioner is all the way back. So, I put a new one in, and it starts doing the same thing.
I should add it runs great. Timing belt definitely did not jump a cog. It idles well, and there is no lag.
What could be causing this?
Thanks guys.

It's a 1995 300zx TT

 

Okay guys. So I'm completely out of ideas. I was just doing a standard timing belt change with the pulleys. Everything is going fine, all the timing marks are right on, except the belt is pretty tight. So we put it all back together, drive it around, everything is great.
Then, after it's all warmed up, it starts knocking at around 3k, so I limp it home. tear it all apart, and notice that the tensioner is all the way back. So, I put a new one in, and it starts doing the same thing.
I should add it runs great. Timing belt definitely did not jump a cog. It idles well, and there is no lag.
What could be causing this?
Thanks guys.

It's a 1995 300zx TT

 

If the only thing you have done differently is the timing belt then you need to go back and recheck your work. If you read the manual on how to do the timing belts they are very tedious, temperamental and just a pain because of how difficult it is to pull everything apart. Trust me I know. But in the installation it requires you to set one side and them rock the engine back a bit set the other side and then rock it back again and check the marks. If everything is good it states to rotate it 2 full turns and then recheck the timing marks because very often it will not be right. I was always taught if it was working fine before the change...and it's not working after the change then its something I've done wrong. 99% of the time when I follow that rule of thumb I go back and realize there was something I missed or did wrong. It maybe something small you may have over looked. These cars can get to a person and its easy to miss something small.

Also make sure your CAS is set correctly. If the timing is off it will cause a knock too.

I hope this helps. PM me and let me know if you have any questions or need a quick walk through.