misfire that won't quit
I think I'll rename the truck Miss Fire. Because that's all she'll do.
'63 Champ OHV6 .The truck was running fine 3 weeks ago, with the excpetion of 'normal' Carter RBS problems, like worn throttle shafts, and leaning out badly over 3200 RPM. I had bought an AS 3370S from a '62 Lark that supposedly ran well when it was parted out. I bought a kit from Sudebaker International, and installed it. I did NOTHING else to the truck. The truck ran so poorly, I did not even try to drive it. Anything over 1/4 throttle, and it popped, backfired, stuttered, and just generally ran like cr@p, but it idled very nicely. After tiring of fooling with it and needing to drive it so I can do some badly needed work on my DD, I put the RBS back on.
Guess what, it runs EXACTLY the same as it did with the AS! It is simply not driveable as badly as it backfires. The first step was to check for any vacuum leaks. The intake gasket is not old, and the nuts are snugged down. Carb base gaskets are in place, no leaks visable. Used carb cleaner to try and look for leaks, found none. Stethescope, nothing. The fuel bowl in the pump is full and clear, and although I did not measure it, the fuel bowl in the AS was full enough I expect I've got decent volume. I did make a run to Lowes, and it was awful, anytime I opened the throttle enough to drop the vacuum, it missed and backfired continuously unit I let up on the throttle enough to increase vacuum, where it would smooth right out. Going slightly downhill so I didn't need much throttle, it would wind up to about 3500 without a problem...untill I'd try and open it up some more.
Even though it has a distibutor that was rebuild by Bill Cathcart 5,000 miles ago, with a Pertronics ignition, new wires, cap, rotor, plugs etc., this is where I looked next. The spark plugs all look great, nice and tan with no fouling or deposits, and gaps are fine. The wires are clean too. I pulled the districbutor cap, and checked it carrefully, and found no problems. I checked the spartk, it's a nice hot blue spark at 3/8". The dwell meter stays steady, even when backfiring, so I think this indicates the rebuild is OK. Timing is also on the mark, and advances as it should. I checked all primary wires for problems too, nothing. I rerouted the plug wires to see if there was some inductive misfiring, nothing. I even checked the firing order, though how it would change is beyond me, it been in a locked garage since I started. I feel really safe in saying the ignition system is not the culprit here.
I am stumped. I did nothing but change one carb for another, had problems, went back to the first carb, and still have the same problems. I really need some help, because I need to drive it while my DD is being repaired.
Thanks
Ron
'63 Champ OHV6 .The truck was running fine 3 weeks ago, with the excpetion of 'normal' Carter RBS problems, like worn throttle shafts, and leaning out badly over 3200 RPM. I had bought an AS 3370S from a '62 Lark that supposedly ran well when it was parted out. I bought a kit from Sudebaker International, and installed it. I did NOTHING else to the truck. The truck ran so poorly, I did not even try to drive it. Anything over 1/4 throttle, and it popped, backfired, stuttered, and just generally ran like cr@p, but it idled very nicely. After tiring of fooling with it and needing to drive it so I can do some badly needed work on my DD, I put the RBS back on.
Guess what, it runs EXACTLY the same as it did with the AS! It is simply not driveable as badly as it backfires. The first step was to check for any vacuum leaks. The intake gasket is not old, and the nuts are snugged down. Carb base gaskets are in place, no leaks visable. Used carb cleaner to try and look for leaks, found none. Stethescope, nothing. The fuel bowl in the pump is full and clear, and although I did not measure it, the fuel bowl in the AS was full enough I expect I've got decent volume. I did make a run to Lowes, and it was awful, anytime I opened the throttle enough to drop the vacuum, it missed and backfired continuously unit I let up on the throttle enough to increase vacuum, where it would smooth right out. Going slightly downhill so I didn't need much throttle, it would wind up to about 3500 without a problem...untill I'd try and open it up some more.
Even though it has a distibutor that was rebuild by Bill Cathcart 5,000 miles ago, with a Pertronics ignition, new wires, cap, rotor, plugs etc., this is where I looked next. The spark plugs all look great, nice and tan with no fouling or deposits, and gaps are fine. The wires are clean too. I pulled the districbutor cap, and checked it carrefully, and found no problems. I checked the spartk, it's a nice hot blue spark at 3/8". The dwell meter stays steady, even when backfiring, so I think this indicates the rebuild is OK. Timing is also on the mark, and advances as it should. I checked all primary wires for problems too, nothing. I rerouted the plug wires to see if there was some inductive misfiring, nothing. I even checked the firing order, though how it would change is beyond me, it been in a locked garage since I started. I feel really safe in saying the ignition system is not the culprit here.
I am stumped. I did nothing but change one carb for another, had problems, went back to the first carb, and still have the same problems. I really need some help, because I need to drive it while my DD is being repaired.
Thanks
Ron
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