There just seems to be less trouble with the 4 pin system. One less circuit to fail that isn't needed anyway. I've had two trucks that just flat wouldn't work right with the stock 5 pin module but just changing to the 4 pin the truck runs fine. We diagnosed the system untill we were blue in the face but could find the problem. (a no-spark condition would come and go randomly) Seemed every time we put a meter on it, it would start no problem! It wasn't the module because we put it into another vehicle and it works fine. Something in that extra circuit in the vehicle wiring was the culprit but it wouldn't act up long enough to pinpoint the problem.
