1985 jetta wont start

I let my jetta sit for about three days and now it wont start. I have changed out the ecu a couple of times(little box on top of the brain). it has fresh gas and turns over fine. I also have just done the cap, rotor, plugs and wires within the last 1000 miles. ran great when parked. it has an 85 gti 1.8 8v engine in it. both fuel pumps are coming on I can hear them. please let me know if you have any ideas, thanks for your help