Timer design

I need to make a timing circuit to turn on the high idle function on a diesel engine.  I know what lines to tap into, just not sure about putting together a simple timer.  It's been 25 years since I have done much electronic work.   I need to have the timer trip a 12V relay.   Can anyone give me a quick and dirty or point me in the correct direction?  Thanks,jc

Wasilla, Alaska

Heres the best way I can think of: You can design your own circuit using a 555 timer. Check out these basics http://www.circuit-innovations.co.uk/555.html use a monostable timer setup, just have the output engage a relay more info: http://ourworld.compuserve.com/homepages/Bill_Bowden/555.htm