Thank you. I thought it went there. I was told different. The car back fires trying to start. Timing off?

I took the pick up sensor off when I replaced the water pump. Out it back on. There is not much to it. Align directly over fly wheel sensor.

Originally. The car motor was washed After that the car ran very rough 3-4 cylinders it seemed like. I put it in garage and did the water pump. Three weeks later tried to start. And that when it back fires. Just once or twice. There is fresh fuel. There is a spark. I ovp breaker is good. The car ran great before I carefully washed the motor So Maybe a vacuum hose was knocked off. I have looked everywhere to find nothing. My diagram from the MB CD is vague for hose lay out. Where would I go from here, besides to the bar.