Starts when cold, then won't fire again

[nkopp]

It is sooooo close.

When the car is cold, it will fire and purr for about a second or two. After that one time, it won't start again. It will get close, but it puffs whiteish smoke out of the carbs every few revolutions. I can come back the next day and it will fire up and purr again (once). 

Any ideas what could be causing that?

Stuff I've checked:

• Spark - the fact that it runs so smoothly for that second or so makes me think it has a fine spark. This had been the most previous issue and I redid the distributor (new cap, rotor, and condenser). 
• Fuel - Both SU carbs have fuel in the float chamber. I spun the bolt off the bottom of both and there's fuel in both. I am running off of a jerry can that's sitting on top of the car (with a return line back to the can). I can see fuel moving through the filter when the starter turns.
• Compression - Cold compression test is consistently at 130PSI on all cylinders. 
• Battery - The battery turns the starter just fine. I've been connecting it to a trickle charger after I work on it. 
• Timing - I've been twisting the distributor around and trying a few different positions, but none seem to make much difference.
• Choke - I have been leaving the choke on for all of these tests.  
• Fuel/Air Mix - I had set the needles at 2.5 turns down, but the spark plugs were getting really sooty, so I gave them a twist in the direction of more lean. 

Thanks for any help!

[Zed Head]

1 hour ago, nkopp said:

When the car is cold, it will fire and purr for about a second or two. After that one time, it won't start again. It will get close, but it puffs whiteish smoke out of the carbs every few revolutions. I can come back the next day and it will fire up and purr again (once). 

Might help to describe the engine.  Carbs, igntion, etc.  You've probably mentioned it in the past but searching past posts is work.  You could also put some stuff in your Signature.

Guessing that the filters are off?  (You can see white smoke.)  Both carbs puff or just one?  One second is not much.  Neither is two.  One one thousand, two one thousand.  Are you sure it's not running longer?  How can you see several "few revolutions" in one or two seconds?

One more nit-pick - if it's puffing out of a carb or carbs, is that "running smoothly?  Hard to grasp what you're describing.  Might be a sticking intake valve causing the puffing.  You might be able to discern between ignition and fuel with starting fluid on the restart problem.

[Patcon]

After it runs what are the compression numbers?

What year car? Signature line?

What ignition system?

[siteunseen]

Sounds like it's running out of fuel in the float chambers? Try sticking a little hose down the over flow bung on the lids. The little small red ones off WD-40 work good at pushing down the floats. They should push down and bounce right back up if there's fuel after you run it. 

 

[Zpenman]

Anyone think this could be an issue associated with the ballast resistor?

[Zed Head]

It's been a week.  Who knows.

[bluez]

On 6/28/2024 at 4:37 PM, Zpenman said:

Anyone think this could be an issue associated with the ballast resistor?

Certainly could be.. When I first got my Z, it would suddenly die, sometimes it would restart or not. Thought it was fuel, eventually figured it was the resistor.