Model A Missing Badly
 

My ’28 roadster has been running great until yesterday. I started it in the garage, and it started right up and ran smoothly for about a hundred yards. Then it started missing like crazy as it might if it were starving for gas or way out of time. It didn’t have enough power to drive it back to the garage. I drained the gas tank, replaced all filters and replaced the E-10 gas with E-free gas. I removed the carburetor, checked the float for leakage and adjustment and blew out everything with my air hose. I checked the timing and point adjustment and they were right on. None of this helped.
Any suggestions as what to do next will be appreciated.

Thanks, Robert

Re: Model A Missing Badly
 

If you have a spare condenser - swap.


Pull the plugs and inspect. Perhaps fouled or dirty. Clean and re-gap.



Disconnect the plug leads with the plugs in, space the leads from the plug terminal about 1/8 inch, all equally spaced. Start car, each gap should have a nice blue spark and each gap/spark should not miss.


This hopefully will narrow down if it is electrical/ignition.
Let us know results, try diagnostics to narrow things down before swapping parts/trying things.

Re: Model A Missing Badly
 

With it running carefully remove one spark plug wire at a time. Listen, you should be able to identify which plug is not firing properly. If there is a change, it's not that plug. If no change you have narrowed it down.
Now follow the advice from 30 Closed Cab PU
Don't just start replacing things. Find the cause and as always "Enjoy the adventure." Chap

Re: Model A Missing Badly
 

I'm currently chasing an intermittent high speed miss. Still checking through the ignition system. 9 times out of 10 a fuel problem is actually electrical.

Re: Model A Missing Badly
 

Do you have wireless plates or electronic ignition?

Re: Model A Missing Badly
 

Good Morning...You might check the distributor body and cap. The bodies can crack and if you can start the car in the garage...you can sometimes see the spark escaping. The little metal connector that rubs on the little tit in the top of the distributor cap can fail to make contact after a few years. Examine the tit for wear and if it looks good bend the metal strap on the rotor and see if the problem is fixed. Also check to see that you have 0.025 thousands between the rotor tip and the four studs that go to the connectors on top of the distributor body. Ernie in Arizona

Re: Model A Missing Badly
 

Something easy to check is a manifold leak. Get it running and spray starter fluid on the intake gasket area and the manifold itself. If anything changes, that’s your problem. Easy fix. Good luck

Re: Model A Missing Badly
 

Many thanks.

I was thinking that it might be the condenser although I just replaced it about 6 weeks ago with a “Short Proof” one. Sure enough, that was the problem. I had 5 spares, 2 of the old type and 3 of the new. The second one I tried (new type) worked. I think that I need to replenish my collection of these.

Thanks again, Robert

Re: Model A Missing Badly
 

I had a similar problem that was caused by sticky new stainless steel valves and guides . It has been said that using new stainless steel valves with new replacement, original style valve guides can cause a sticky situation . After adding a liberal amount of Marvel Mystery oil to the fuel solved the problem . I now mostly add four ounces of Marvel Mystery oil to each ten gallons of gas that is used in the car .

Re: Model A Missing Badly
 

Some run their spares for awhile to make sure they are good. From what others have experienced it is not uncommon for non A and Ls to go bad shortly after installation. A and Ls do not go bad as often.

Re: Model A Missing Badly
 

I see you are located in Texas. What was the air temperature down there? 100 yards is a short distance to have this happen, but if it was very hot, it could have been vapor lock caused by the fuel boiling in the carb and fuel line.

Re: Model A Missing Badly
 

Re: Model A Missing Badly
 

Did it run long enough to cause vapor lock?

Re: Model A Missing Badly
 

Have you determined whether it’s fuel or spark???
You can give it a shot of ether after it quits running and if it coughs and briefly fires, it’s obviously a fuel problem.

Re: Model A Missing Badly
 

Mine did the same thing last year. Found out the screw that holds the timing cam in place had loosened up. New cam and screw solved the problem for me.

Re: Model A Missing Badly
 

Post 8 says it is fixed, he had a bad condsenor on a 6 week old short proof replacement condenser.

Re: Model A Missing Badly
 

Happens all the time doesn't it.

Re: Model A Missing Badly
 

Thanks for reporting how you fixed your problem !

Re: Model A Missing Badly
 

Mine was missing badly and then I looked in my other barn and found it. Not missing anymore !

Re: Model A Missing Badly
 

I'm beginning to have the problem too. :D