Hi everyone,

I have a '69. The engine is a 454 block with stock 427 heads/intake Holley carb. Everything else is stock. I recently installed a new distributor because my old one didn't have the tach drive output. I selected this one because I thought I would be a nice upgrade over the stock:

1962-1974 Corvette Dragon Fire Pro Series Electronic Distributor w/Tach Drive (Black Cap) (Dragon Fire DFD1009BKF) (zip-corvette.com)

Since installing I've been having tons of "coldish (i.e. first start after 8+ hours after sitting in the sun on an 80 degree day), warm, and hot start problems. At this point, I just can't figure out what's going on. It starts right up on a cool morning. When warm, it just cranks and cranks but will start once I put in a whole lot of starter fluid. This video is what it does when it's between warm and running temp, note the "coughing" which is at least partial ignition because it sends smoke out of the pipes. The video was taken after sitting in a parking lot for ~15 min on a 70 degree day. It was fully up to temp before parking. .

I'm 99% sure this is spark related. The accelerator pump is shooting fuel into the carb so no vapor lock or boiled off fuel in the bowl. The choke works and I'm pretty confident it's adjusted correctly (is open maybe 1/8th of the way on a warm and on a warm-day start). I've varied my starting routine, everything from no pumps before start when warm/hot, to holding down the accelerator half way, to full way, to a couple pumps before start. Nothing works. To get it coughing like it is in the video i need to hold the accelerator down or press it and release; without this it'll just crank. Things I've tested:

- Coil resistance (primary and secondary) all within spec. It's an MSD coil and is nearly new with maybe 1000 miles on it. The ballast resistor is installed as recommended by Zip in the dizzy description. It's this one: - I've messed around with timing. Initial timing was at 18 and I've moved it up to past 25 and everything in between. My old distributor had too much initial timing which is why I thought this was related. Timing hasn't made the problem better or worse
- Confident the battery is fine. Again, this didn't happen until the new dizzy was installed and the same battery is in use. The battery cranks for a really long time. One test I haven't done yet is a jump when things won't start but that seems like a stretch since it starts right up when things are cool

Other things that are likely not related are compression (was north of 145 PSI and all cylinders within 5 PSI just a couple thousand miles ago), I only use non-ethanol 90 octane fuel and have no reason to believe it's bad fuel. Plugs aren't brand new (maybe 5K miles?) and aren't fouled...again, starts fine when cold. The car runs great once it's started. At this point I'm banging my head against the wall. This absolutely did not happen last summer so I'm leaning toward something wrong with the dizzy but want to exhaust my other options first. Help greatly appreciated!

 

I thought the dizzy description says you do NOT want the resistor?

 

That's not what I read from the link provided.

 

When the car is fine. You change one thing. Now the car is not fine. It does beg to question. What did you stuff up on this install.
Now of course it could be unrelated. But......
It begs to question.
What did you stuff up.
Most modern distributors do NOT run a ballast resistor. I'm questioning that as well.

 

Thanks everyone. I read that description very differently as in the oil filled doesn't have a ballast and therefore is problematic. Good to know ballast is not for modern distributors. I'll get a new coil and report back.

EDIT: After reading up on what a ballast resistor does I realized I could just bypass it with my current coil. Can you tell this is the first time I've had to deal with this type of thing? Will do this and report back.

 

Thought I'd close the loop in case anyone runs across this thread in the future. Removing the ballast resistor did indeed fix all my problems. Yesterday was 85 degrees and the first truly hot day since removing the resistor. I parked in the sun while I was at work and ran a couple of errands and started while warm with zero starting problems. After reading up more on ballast resistors I learned that their resistance increases with temperature (can you tell I'm a mechanical engineer rather than electrical??). Likely spark was so weak at running temp it barely kept things going and wasn't enough when running off the battery's 12V and the resistor was warm/at operating temp. Resistance was probably low enough when cold-starting that spark was good enough to get things going.

Thanks for the help everyone!

 

Your welcome and we are all happy to hear your problem is fixed!