Exhaust popping

[David M.]

Re: Exhaust popping

Need more data to efficiently trouble shoot over the net:

Before you get crazy tossing parts at it and crawling down the rabbit hole lets get some basic troubleshooting out of the way.
What is the initial timing set at?
What is it with the vacuum advance plugged in?
Did you verify the centrifugal advance assembly is intact?

1. Verify the neg wire from the coil to points is good...wiggle it with an OHM meter attached. You are looking for an open.
2. Verify voltage to the coil during cranking and when the key is released engine running. Should be 12 cranking 8-9VDC running.
3. Verify the coil primary & secondary resistance and no short to ground is present.
4. Cap & rotor condition? I've seen a bad rotor or distributor cap cause this. New doesnt always = good. Closely examine both.
5. Ohm out the ignition secondary(spark plug) cables including the coil wire.
6. Read the spark plugs. What do they say? I seen a faulty or fouled set of plugs do stupid things.
7. Any side to side play in the distributor shaft?
8. What plug wires and spark plug brand & type are you running?
9. Plug Gap?
10. Vacuum reading at curb idle, engine warm?

[Ralph E.]

Re: Exhaust popping

Nice write up!

[Mark P.]

Re: Exhaust popping

Gentlemen, after a lot of trouble shooting I have discovered the problem with the help of the Holley website. The problem was in my carb the whole time. I did not have the vacuum choke set properly. With the engine cold. release the tension on the adjuster cap on the side of the carb. Crack the throttle a little and load the choke spring until the damper starts to move. Set the spring tension there. I had to much choke and the engine was running lean. Also, the needle and seat are to be set at 2 1/4 turns open. I was at 1 1/4 turns. They also suggested I disconnect the vacuum advance from the distributor but that was a terrible idea. Drove the car and it ran 98% better. Going to adjust the needles 1/4 turn (per Holley direction) to adjust. Want to thank everyone for their help and input. Mark