HOW TO FIND PROBLEM CAUSING SUCH HIGH HC READINGS, CAULING FAILURE OF EMISSION TESTING
1991 Mercedes Benz 500sl
Idle is rough and at 2500 rpm engine has 900 ppm HC and you can hear and feel the miss. New pluges instaled.
Friday, September 2nd, 2011 AT 10:09 PM
You've pretty much answered your own question. HC is basically unburned fuel, usually caused by incomplete combustion and a misfire is exactly that. You need to locate and resolve the misfire issue. Look first at plugs, wires, injectors, etc.
Friday, September 2nd, 2011 AT 10:34 PM
Could be an ignition misfire, lean misfire and low compression