Backfires instead of starting

Did this get fixed? I was going to say that the points May be shorting or that radio noise condenser May have been on the negative side of the coil, which would throw off the capacitance of the primary side, delaying ignition timing and causing the backfire.
Could it be the non-firing cylinder has a bent pushrod that let go? That would make the backfire and sound like messed up over compression too because the air gets in, but not out of the cyl very well.
 
Im not sure if I know what you mean by the radio condenser being on the negative side of the coil? Thanks for your response though, its still not firing. Im thinking it could be a vacuum line issue.
 
What the carnuck is referring to is the rfi noise suppressing capacitor, which is a small cylindrical object that is attached to the top of the ignition coil bracket and has a short, spade-terminated wire connected to the coil. Many people incorrectly refer to this item as a condenser, which is similar in appearance, but is located under the distributor cap on breaker points equipped vehicles. The sole function of the capacitor is to reduce electrical noise that could be transmitted through the stock am sound system (can't believe I called it that) while the engine is running. With today's better insulated spark plugs and wires, this item is redundant and can be omitted with no ill effect on engine performance.
 
scoutboy74 said:
what the carnuck is referring to is the rfi noise suppressing capacitor, which is a small cylindrical object that is attached to the top of the ignition coil bracket and has a short, spade-terminated wire connected to the coil. Many people incorrectly refer to this item as a condenser, which is similar in appearance, but is located under the distributor cap on breaker points equipped vehicles. The sole function of the capacitor is to reduce electrical noise that could be transmitted through the stock am sound system (can't believe I called it that) while the engine is running. With today's better insulated spark plugs and wires, this item is redundant and can be omitted with no ill effect on engine performance.
Click to expand...

The rfi capacitor is essentially the same as the ignition condenser (and often has been used in a pinch when the one in the cap dies) if the vehicle does have a points system and the rfi condenser is attached to the negative side of the coil, the dual mf will burn up the points (over capacitance has as bad an effect as too little capacitance on points)

if it is instead presto-no-lite ignition system then all bets are out the window except maybe soldering the wires together and bypassing the connector at the dist. (as Jeep did routinely per a tsb issued in '77)
 
All the more reason to remove the damn thing. It isn't needed and eliminates one potential variable from the equation. Most engines will run albeit poorly, even with a vacuum leak. I still believe the non-start is due primarily to a timing issue. Erratic starter cranking speed is symptomatic of this. The poofs exiting the carb indicate that combustion of some sort is occurring, just not at the right time. Yeah, there are other contributing factors that must be addressed for optimum performance and reliability. Over the course of this thread though, I haven't felt much confidence in the accuracy of the timing or the methods employed to set it.
 
I like getting rid of things I don't need on that motor, so consider it gone. What should I do with the rfi wires? Completely remove or just cap them off individually? Scoutboy is right, I need have the sucker properly timed. Im hoping to have that done by this Wednesday, then look into potential vacuum problems that May have been caused by the blasting backfire it had the last time it was running. Thanks so much for still helping fellas.

Jon
 
What wires are you talking about? There are no such things as rfi wires. The part in question has one short wire coming out of the center of it. That's all. It sits on top of your ignition coil bracket. Don't remove anything else at this point.
 
Issue solved. When my distributor was replaced about 7 years ago, some monkey put it in 180 degrees backasswards. So when I went to wire it from the manual instead of marking where the wires came from - I hooked them backasswards (even though I was technically right). Timed it, its running and looking like a beast. Just had it in its first car show. Thanks for all the help. I attached a picture for you guys...
 

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