Hi Frank. Thanks for the very useful info. I will check the ICU tomorrow to see if there is an obvious problem. I may have difficulty getting another unit without purchasing it new as the car is in Malaysia and there are only a few of these left around the place here and parts are hard to come by used. I assume the ICU will be fed from various sources including the Lambda sensor and crank position sensor and MAF (if it has one??). I am wondering if I can put a meter across the pins to see if the pulse originates before the ICU or only after it? ED