Sounds like a voltage problem to me...had this problem on a chevy and when it drops below 9 volts the computer will not function. What voltage do you have at the battery with the car running? Battery could be already drained running a negative draw. I would fully charge the battery on slow charge overnight with a battery charger, then test your alternator output charge after doing that. Check that you dont have a broken ground strap to the engine as well.
