Vrooom ... dadadada .... vroom .... dadada

Bruce

Bruce

Senior Member
I know that this has been discussed before, but now it's different. It's my problem!
Just finished a 325 mile daytrip yesterday. The Roadster ran well until we got within 10 miles of home. Then, out of the blue and at 40 mph, it died. 50 wheel turns later it ran strong for about 50 wheel revolutions ... then it died ... then it kicked in, etc. all the way home. And it backfired, but not as much as you would expect. Kind of a complaining "put, put, bamm" at intermitent points.
I had had this same symptom several weeks ago and had fiddled with many potential causes. Phred helped by opening the points just a smidgen. Now they are "exactly."
Valves are adjusted.
Carb is a good one that I swapped off of the Roadster Pickup just for the trip. Oh, I wish I had three like this one!
And the car ran well for 315 miles. Sure thought I'd whipped it.
So, 10 miles out I started trying stuff. The spark advance/retard did little to help the situation. GAV didn't do much, either. I stopped and took off the gas cap. Left it 1/2 thread on -- not tight. And I dumped the sediment bowl.
No change. Just enough zoom to get to third and then puttttt.
And then, when we turned onto the state route for the last 3 miles, she ran like a champion. Not a hickup or a pop. Like it never happened.
When I got her into the garage I shined a flashlight into the gas tank. There is some sediment in the tank, but not very much. If I could get my hand in there I could wipe it all up with a swipe of my thumb.
We want to ddrive this car to Amana in two weeks. What would you attack first?
(Thanks for covering old ground one more time).
 

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How hot was the coil? Any loose connections causing intermittant heating or resistance?

Diagnosing something when the issue is at hand is a better time. How much fuel was in the tank creating head pressure? How hot was the fuel? Removing a fuel line at the carb. to test the fuel flow is "better". Removing the carb. bowl and watching fuel flow is "best". This allows you to know whether the fuel is actually being restricted (dirt, dry Grose-Jet, sticking needle, etc.) into the bowl. The sediment is a possibility but can be looked at when the bowl of the carb. is removed and the passages blown out.

Your comment about being able to wipe out the sediment is one that most people do not realize. Just like an iceberg, what you can see is never really how big the problem is. Looking behind the baffles and the bottom-side of the top of the tank is ALWAYS where the rust is.
 
I had the same thing happen in Dallas at the 2008 meet.

It was a faulty condenser in the distributor.

I changed the condenser and had no problem after that
 
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Bruce: I would certainly be concerned first about the ignition system. All three of the items already suggested can be the source of the intermittent problem. I would vote to first look at the coil, that is easy to change. Then I would be concerned about the switch. I had a very similar problem as yours on my way to Amana last year. I changed condensers twice and then found, as Brent suggested, that the coil was hot. Replacing the coil fixed the problem. Unfortunately, I didn't have a extra coil with me but fortunately, a half mile behind me was a John Deer dealer who had one in stock. Gar Williams
 
Faulty wire or sliding contact between upper & lower dizzy plates? Popout cable end contact to lower plate pushing (shorting) lower plate to casting? Worn wire inside popout cable? Loose connection at popout stud or coil terminals, ammeter or terminal box? Battery terminals or ground to frame loose?
 
I believe all the above suggestions regarding electrical are the way to go. One of the best lessons I learned was that if you think it's the carburetor - check your ignition first. 90% of the time the carb and fuel is fine and it's an electrical issue.

Good luck!
 
Does the car have a modern upper plate with condensor on upper plate or have a condensor mounted somewhere else other than stock?

If so remove upper plate and look closely at the lower plate where the condensor screw is normally fastened to the lower plate.

You might find that the far end of the plate is shorting on the inside of the distributor housing. Mine went on for some time until finally enough paint was rubbed off that the problem went "solid" enough that I found it.
 
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