I was gonna say it like 2 days ago, but hoped that maybe it was gonna be something else for you.
Yeah, the tensioner pulley for whatever reason is super sensitive to a belt that is tight.
"Correct tension" is where the belt flop in the trailing edge of the belt between the exhaust cam and the crank pulley when revving up is a "wtf, this doesn't look right" kind of thing. It will literally flop like 1/4" from the centerline at the middle point of the belt between the exhaust cam and the crank pulley, when at like 3-4000 rpm. It looks sketchy when the guards are removed, but this is what you get when the tensioner spring is the one solely doing the belt tensioning, which is the way Honda intended. You also get no noise from the tensioner afterwards. Any tighter than spring tight, andyou begin to get that indescribable whine when you rev the engine.
You shouldn't have to remove everything to re-tension the belt, Honda thought about this a little lol.
NOTE: Only follow the below procedure if you reinstalled the tensioner spring! If your tensioner pulley doesn't have a spring, this will not work:
See the small teardrop looking hole in the TB cover above the crank pulley hole?
That is your timing belt tensioner bolt access hole.
As long as you have the spring installed, the procedure for re-tensioning the belt with all covers on is as follows:
- Pull #1 spark plug out of #1 hole. Install a compression gauge. This is so you can find TDC#1 during compression/power stroke when both valves are closed, and NOT during exhaust/intake stroke.
- Turn the crankshaft over until the balancer mark lines up with the TDC mark, keeping an eye on your compression gauge. If a bit of pressure began to build leading up to you reaching the TDC mark, the intake/exhaust valves are closed, and you are on TDC#1 compression/power stroke, and move on to step 4.
- If you didn't get a pressure bump on the gauge when rotating to TDC mark, turn the crank another 360 degrees until you do.
- While at the mark under TDC#1 power/compression, loosen the tensioner bolt through the access hole a full turn, turn and a half.
- Turn the crankshaft pulley a bit more, roughly 30-45 degrees, enough to turn the cams 2-3 teeth. This puts tension on the side of the belt between the exhaust cam and the crank sprocket.
- Once you've done the approx. 30 degree turn, simply tighten the tensioner bolt to spec, and restart the car.
If you turned the crank too far at step 5, tighten the tensioner bolt and restart this process from the beginning.
The goal of this is to tighten the trailing edge and loosen the leading edge of the belt between the crank and intake cam sprockets, allowing the tensioner spring to do its job and pull the belt on that side tight.
You should be good after this.