hi my 1991 300zx wont start when i turn the key to start it the secuity light just flashes and the engine dosnt even try to turn over what do i do to reset the secuity system?

is it the original key? had you had issues prior, hesitation, key loose in ignition? the "tumblers" in the ignition get worn out, and don't acknowledge each other any more. you can try to have a key made, but is most likely too far gone for that. there is no "reset" for security, there are fuses but can be very tricky, i would call any key/lock company and price out a new key and ignition tumbler, then find one online and consider that. does the key have a "resistor" in it, or a regular key?

I had a problem like this when I lost my remote.My mechanic found a fuse under the steering wheel that you can remove and you have like one minute to turn on the car before the alarm gets activated again.This was a real pain for me but I was lucky to find the only remote I have after a few days.The fuse was real hidden below the steering wheel but it was hard to see so get a nice and bright flshlight and good luck!!!

These z cars have a two stage security in them,under the passenger seat there should be two small boxes under an opaque plastic cover one will say security module the second will be black plastic w a small pig tail that connects the two if the module has been wet replace both, used is fine. Note the security is powered by a timer control unit,that controls dome lights dimmer,security,and the heater controls if not manual. I know in my 86 the timer was near the blower fan , the electrical part of the ignition may be worn out is a easy do it ur self fix,new can be spendy ,genuine is the way to go done once, cheap do it many times

Sometimes these cars go into park but not all the way I'd try pushing the break putting it n N then start it might not b so complicated!

Security alarm comes on with batterie Hook up ,will not shut off