Samurai Timing Problems
Last week, I performed a tune-up on my '87 Samurai and set the timing to 10 degrees BTDC after adjusting the idle to 850rpm per the factory instructions. The Sammy ran great for several days until I noticed that the idle had jumped up to 1100rpm and there was now excessive "pinging" during acceleration.
I rechecked the timing and was surprised to see that the 10 degree mark had advanced enough to no longer be visible through the timing window. I corrected the timing and for the next several days, the Sam ran like new with little or no "pinging."
Today, I noticed that the excessive "pinging" was back and that the idle had moved back up to around 1100 rpm. I checked the timing and again, it had somehow advanced itself. I checked my distributor hold-down bolt and it was tight. I checked the tension on the timing belt which was also within spec. What could be causing this problem?