According to the traditional concept of this phenomenon should check the carburetor heat idle speed compensator, because hot idle compensation valve is designed to improve heat idle and warm start performance. But after inspection, the hot idle compensation valve is working properly, no leakage. So concentrate on examining the ignition voltage. Taking into account the cold when idling but heat engine idle speed unstable, respectively, in cold and heat engine check high voltage spark found cold machine high voltage spark strong, heat engine high pressure spark is weak, judged to be the ignition coil internal short circuit.

According to the analysis: large coil short circuit fault, often appeared in the hot state. This is because under their coils in cold contraction, not easy to form a short circuit, while in line thermal ring expansion, short-circuit fault can easily be demonstrated.


After ignition coil replacement retest vehicles, fault exclusion.