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Clicking noise when starting

19 April 2006
Just a couple of weeks ago my 1994 NSX made a clicking noise when starting the car. Not every time I start the car. The clicking noise will stop after 10 to 30 seconds. It seems to be coming from under the dash, to the right of the radio and left of the glove box. It is a loud clicking noise. Anybody have an idea of the source? Thanks for any input.
To the right of the radio and the left of the glove box is the general area for the starter cut relay. I don't know why the relay would start clicking unless like Drew asks it is tied into an aftermarket security system of some sort which has gone south.

With the ignition switch in the run position (engine not running), press the clutch down and then release it. This should cause the starter cut relay to close and then open. Does that sound like the noise you are hearing? If so, you might want to investigate further. If the starter cut relay craps out or the associated wiring has a problem a failure can leave you dead in the water - the engine can run; but, you can't get it started.
Thanks for the replies. I didn't buy the car new but have owned it for 26 years, have 200,000 miles on it and am not aware of any after market alarm systems. This clicking just started a couple of weeks ago. It does not affect the starting or driving of the car and when it does happen it goes away after 10 to 30 seconds. All systems, gauges seem to work fine when it happens. The security system from the factory does work, other than some times over the years if I unlock the driver door it will set off the alarm. So I normally unlock the passenger side door first and the alarm has never gone off in that case. Go figure.
I went out and did what "Old Guy" suggested and nothing. No clicking. Then I stated the car and no clicking. Again, it happens maybe half the time at start up. Mystery??
I was finishing up some work on my car last night so I did my suggested test with the clutch pedal and I could not hear noise from the relay so I think that is normal. I had never recalled hearing anything; but, I had never really payed attention to this.

The starter cut relay is the only obvious relay that I can think of in that area. The power door lock control unit is also in that stack of modules that is in the same area. Honda provides no details about the internals of the unit. Aftermarket security systems typically use electromechanical relays to switch the lock motors; but, it would also be possible to use power transistors to do this. If the power door lock control unit uses relays it is possible that one of those relays is chattering; however, if the relay chatters I would expect that this would cause noise in the door lock motors. @drew has a detailed interest in the NSX lock systems and may be able to advise whether the power door lock module uses output relays. I can't think of anything else relay-like in that area. Most of the relays on the NSX are out under the front hood, some of which are mounted on the firewall in the area you describe. If the problem consistently re occurs perhaps open the window to see if the noise is originating under the hood and being transmitted through the firewall.