I have a 71 Plymouth Duster 340 (very modified). I just changed the oil a few days ago and the spark plugs. Now when it runs, all it does is back fire. Thats all it does. It backfires it self out (until it stalls out). Sorry this is off the topic but their are some pretty darn good mechanics and tuners on this site that can probably help me with this problem. I need to get this baby up and ready for the races this weekend. Please any feedback or ideas would be greatly appreciated.

 

11SecL,

Besides the obvious of crossed plug wires, badly wrong plugs, or moving the distributor enough to change timing, it doesn't seem like your oil & plug change could be the culprit.

Mark

 

Thanks for the reply. I use the same kind of plugs, wires are not crossed and I have already tried the good old turn the distributor to time it. No dice! I'm thinking I am getting a weak spark or running too rich but I havent checked yet. Just wandering if anyone has had the same problem.

 

Double and triple-check those wires. I crossed some a long time ago on an old Camaro. Try checking the plug gaps. If it still has the old points and condensor ignition, check the dwell also. Also timing. Sounds like its the plug gaps if nothing changed. By the way, my first car was 71 Duster with the 225 slant 6. Was slow but indestructable. Love those 340 engines