SLEEP doesn't apply in your situation. You need code in the timer.fil. RUNTIME is a command that puts how long you've been running into a variable. Do some math to divide this by 4 minutes and look at the remainder. Then use an IF THEN statement to turn on your output during the portion of your 4 minute cycle you'd like.
P.S. If you want to run the oiler only when running a program, take a look at LOADING. It will have a value of 2 when in cyclestart mode.