'72 - Plymouth - Valiant - 198 - Straight Six - tough to start, and rough idle

[natificent]

Hi everyone. I'm pretty new to the world of A Bodies so appreciate any help or guidance anyone can give me would be much appreciated.

Car is new to me and while it ran, it needed a lot of work.

Replaced:

• Distributor
• Distributor cables
• Battery
• Spark plug
• Coil

Car was running great until driving it on a very rainy and humid day last week. Came to a stop at a light, car stalled and wouldn't start again. Had it towed back home and went through a lot of troubleshooting steps, and was finally able to get it to "start" but it was running really rough.

I put an inline spark tester on one of the plugs and while it lights up, it's not really bright. I did a spark test from the same wire to ground and again while it did spark it was pretty weak.

After talking to my mechanic he suggested it could be the ballast resistor. The didn't have one in stock so i'm waiting on it to arrive tomorrow.

A few questions:

• Is it safe to bypass the ballast resistor just to try to get it running. Wouldn't want to run it like that long term obviously.
• Are there other common problem points I should look at?
• Any good troubleshooting guides anyone could point me to?

Thank you

 

[Darter6]

Is it safe to bypass the ballast resistor just to try to get it running.

It's ok for testing. Internet troubleshooting is mostly guessing.
You say the distributor has been replace, 72 should be points type. Recheck gap.
The rain(may) have something to do to with your problem. Not likely but possible.Dry everything, cap,inside distributor with compressed air, check all wires.
Weak spark, Check for a good zap spark at the coil wire from cap to engine block.Could be the coil is weak.
Other thing Slants are known for: Check the carburetor for loos bolts and screws.
This is way out there but intake manifold nuts loose or blown gasket.I've seen it on Slants. A good back fire can cause a world of hurt.Fuel filter checked ?
Check for any vacuum leaks. That's about it without being with the car.

 

[natificent]

Thanks for the reply @Darter6

Replaced the fuel filter as part of the troubleshooting.

I’m going to jump the resistor for troubleshooting see if that works and then if not test from the coil cap to the block.

Will reply with how I make out.

 

[cudamark]

Sounds like something in the ignition system got wet.

 

[Bewy]

Remove the dist cap & check for arcing, carbon tracking [ also check the rotor for arcing ].
OK to run for a short period with bal res bypassed