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Engine revved up to high RPM

16 July 2023
One hot day my NSX (first Gen) started revving up to high RPM and when we diagnosed it was due to some debris trapped near engine. It was cleaned up and I think it's due to the air filter getting ripped. The car has custom filter as shown in the pictures. So, I am thinking of changing the air filter. Any other ideas? Also given the pictures and the serial number can someone tell me the make of the engine air intake so I know?



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That is an interesting 'air filter' because I don't see any air filter at all. All I see is a hose running to the air inlet in the fender. Is the 'filter' supposed to be that black conical thing in the first photo? If so, I expect that it must be more of a lump filter because it won't have nearly enough surface area for a good micronic air filter.

If you want to change the air filter system, changing back to the factory original system would be a good option. The parts are available; but, rather expensive by the time you get all the pieces
If you post a thread in the Wanted to Buy section you may be able to find an air filter housing that somebody has removed from their car (maybe your original air filter :) ?).

It is not clear to me how 'trapped near engine' would cause an engine RPM increase. Do you mean something jammed in the throttle cable mechanism which an air filter is not going to fix or do you mean something jammed in the throttle blade and holding it open? If you think debris has gotten past the lump filter such that it could jam open the throttle I would be thinking about completely removing the throttle body and cleaning it because there is a good chance that there is other debris trapped in the various air control passages. Best not to think about what that debris might have done to your piston rings and cylinder walls.

If you want long engine life the original air filtration system is your best friend. There is no evidence that on a stock engine there is any improvement to be had by replacing or removing the stock engine air filtration system.