This is a common problem on older cars and trucks (no excluding motorhomes -
after all your RV is equipped with a truck engine). Over time and due to
possible timing related repairs, the timing mark plate can be removed and
not replaced. This is apparently the fault in your motorhome's case. Without
the timing mark a proper ignition timing inspection can not take place and
will cause an ignition timing mark "functional" failure. The repair involves
the purchase of a new timing mark plate and installation. Then the timing
can be inspected for proper setting... and if set properly the vehicle pass
the timing mark portion of the smog test.
posted by SmogTips Support
