Quote:
Originally Posted by cycleguy55
I've got the car running again, but get a surge / miss on light throttle cruise between 2,000 and 2,500 RPM. There's also more exhaust 'popping' or 'burble' on throttle-closed deceleration than before I replaced the ignition box and coil. There are no apparent issues at idle, when accelerating, or cruising < 2,000 RPM. I have not yet checked the timing but, other than replacing the magnetic pickup and distributor cap, the distributor was not touched.
Environment: - MSD 8477 distributor (magnetic pickup swapped from old MSD 8577 distributor in process of getting car running)
- Summit Multi-Spark digital ignition control box p/n , mounted behind dash ( https://www.summitracing.com/parts/sum-850610 )
- Summit Epoxy coil ( https://www.summitracing.com/parts/sum-850500 )
Questions: - Does this sound like an ignition or a fuel issue?
- Where do I start?
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The miss is happening at where you would have the maximum amount of vacuum advance, at light throttle, and also on deceleration if using manifold versus ported vacuum.
If the rotor phasing is now wrong because of the module change, you need an adjustable rotor, and a sacrificed cap for testing.
I experienced this phenomenon many years ago when I made my first electronic advance module in kit form, but rotor phasing wasn't taken into account at the time.
Gary