Honda prelude engine knock when decelerating?

[Drew]

So i was under my hood revving the engine a bit when I noticed after revving, when engine decelerates I hear a knock type noise around 2000-2500rpm before the engine returns to idle. Its quite faint you can really only hear it when the hood is open but it is definitely there. Any thoughts? I think its coming from the lower end not sure though. Thats the only knock noise I have heard it does not knock at all when revving, only when engine is decelerating like I described.

1994 Honda Prelude Si H23A1 all stock 193,000 miles, I got it at 165,000 miles, as far as I know there has been no work done on the lower end.

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[college man]

It may be valve noise and may need a valve adjustment.

http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car

[EricTheCarGuy]

I suspect your timing belt is loose or the balance shaft belt is out of time. I have a timing belt VManual on that engine.

1990-2002 Honda F Series Timing Belt Replacement VManual

I would stay away from the valve adjustment if you’re not familiar with doing it. Check the timing belt tension first however. If that fixes it, I’d leave it be and move on. If you feel compelled to do a valve adjustment.

More info on finding noises here.

http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car

Please keep us updated on your progress.

[Drew]

Thanks a lot, timing belt is due to be replaced anyways I guess its time I bite the bullet and get it done. Love your videos by the way, they have been very helpful to me.

[Author]

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