View Full Version : missfire

BSO one
08-18-2003, 02:20 PM
I have a 496 BBC on Alky the car is 2660 runs 8.90's and has a lite missfire almost like a lean condition but it happens from the hit to the strip somtimes worse than others. I have changed everything except the dist (MSD Billet) I have put in a new pick up and the problem still exists.

08-18-2003, 10:17 PM
A miss-fire can be caused by many different things - fuel, ignition, coil, spark plug wires, rotor phasing, spark plugs, etc. Since you changed most of the ignition components, you can eliminate those out of your search. To help track it down, try changing the engines operating conditions, like reduce the plug gap, richen the fuel system, change the timing, etc. to see which one makes a difference in the missfire. Do one at a time so you can tell which direction to look. If the miss is decreased when you reduce the plug gap then you may be experiencing a secondary voltage breakdown, ie. coil, spark plug wires, spark plugs, cap or rotor. If the miss improves when you change the fuel system then look at fuel delivery from cylinder to cylinder to see if maybe you have poor distribution in one cylinder that is causing a lean miss-fire. Hope this helps you - keep looking.

MSD Tech1

BSO one
08-19-2003, 05:45 AM
What would changing the timing do? It is locked out at 38 deg. is it possible for the rotor phasing to be out with a MSD billet dist?

08-19-2003, 10:04 AM
Rotor phasing could also be a problem, you may want to check phasing. Timing will change the burn time, and could cause lean conditions.