backfire

Just for grins and giggles after this much problem solving and no results, I might check the condition of the timing gear.
 
Its Back! Changed out the plugs! been putting mmo in carb for a couple days as well as a suggestion of STP, Took it out today The SAME results in the EXACT location of the drive????? 1000 mile New engine.!!! When shorting out the plugs-No 2 & 3 engine idles down,No 1& 4 nothing - Does Not Idle down???? Cause????
 
You might have screwed the distributor too far onto the ignition cable. Back it out 2 or 3 turns. Heat expands the cable and it could short out in the dizzy. Tony . Tell us what you find the problem was.
 
I'm not clear what you mean by shorting out 2&3 or 1&4; do you mean shorting out both plugs at once? I remember as a kid discovering that my A would idle just fine with only two plugs connected, but I don't recall which ones.

Also, just to be clear, you did try a different condenser and coil, right?

Steve
 
Shorting out one plug at a time while engine is idling with screwdriver- two plugs make it idle down the other 2 nothing ! Other model a's will make a very noticable difference due to running on three cylinders. Yes with known good condenser and coil.Drove after each item was changed same problem engine dies but will idle. checked ignition cable to distributor.
 
My original old Points and condenser was operating fine with the Original Ford Upper Plate and Condenser below. Just thought I would make a improvement by Installing the Modern Points and Condenser.

I installed the New-Rex upper plate from Snyder's that came with the Points and Condenser. Made up a longer wire on the original lower plate. I had the same Backfiring situation happened to me, when the engine came up to normal operating Temps.
I first changed out the condenser, same problem it would backfire when it got Hot. Drilled out another hole in my Repro Gas cap, no help.
I ordered another set of Points from Macs, installed them, solved My Backfire Problem. Took the first set of Points and Garbaged them.
 
jmeckel said:
Check the copper strap that runs on the outside of the flat spring on the points (it is kind of U shaped). I had this same problem, the strap is too long on some points and will touch the case of the dist. causing all kinds of problems. My '29 Tudor had this problem when I purchased it, took me many hours to find, as soon as it got warm the missing and back fireing would start, let it get cool and everything was fine. All that was needed was to put a little bend in the strap with a needle nose and the problem was solved.
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Tom Wesenberg said:
A vaccum guage connected to the intake while driving might help find the problem. If the needle starts to flicker at the same time the problem begins, then look for sticking valves. A can of Sea-Foam in the gas and another can in the oil might fix it.
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Did you do these things?
 
Jerry,

Dont know if you found the problem but just solved mine after going thru all systems ( a lot of time and work). found out that the new condenser that I replaced was fauly and replaced with anothed new one from napa.no backfire and no miss FINALLY......


J. D.
 
We have replaced the condenser,old style, in fact put in a known good dizzy from another vehicle,Same results. Having the manifold resurfaced as we speak so we will return the verdict when we find the problem.
 

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Update! Checked valves all Good!Compression check 65+ OK! Having Manifold resurfaced waiting for return this week. Put it all back together yesterday. ran it for approx 15 min. Idles super. Started for the test drive 500 ft and No Go!!!! Pulled choke several times while idling and no results. Nursed it back to the garage for further review. We will Return. Same as SGWILSON904. any results there!
 
Your problem reminds of a similar issue that turned out to be small particles and a biofilm that occasionally accumulated on the inlet needle seat of the carburetor. I carried some clear plastic tubing with a plastic fitting on the end and when the stalling/missing/backfiring occurred I removed the fuel line at the carburetor and blew into it until I heard bubbling in the fuel tank to clear the debris.

When I got around to it, disassembling the carburetor revealed very tiny fragments of leather that had spalled off of a leather gas cap gasket. The leather particles were bound into a snot-like biofilm that blocked the fuel inlet right at the needle. With ethanol in gasoline (and the water it absorbs), bacteria, algae and fungi will colonize any organic matter even in gasoline. Water in diesel fuel causes similar slimes.

Changed the gasket and the problem has not re-occurred. You have some humidity up there in Whidbey, yes? At least that is what my nephew tells me.
 
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When it starts to act up, try jiggleing the switch key. I had lots of problems with the low cost ignition switches that are sold by most venders. I now use the pop out look alike switche with good results. Its not a pop out switch but looks sort of like one from the instrument panel side. I had similiar problems with the so called modern points set up. Another thought is, are you running a micro filter , anywhere in the fuel system ? I had similar problems with micro fuel filters. The mesh is SOOOOOOO fine that very small sediment that would run through the system without problems would partially block the filter and restrict the flow, if i feathered the throttle just right I could make it home. many things can cause similar symptoms.
 
Purdy Swoft said:
When it starts to act up, try jiggleing the switch key. I had lots of problems with the low cost ignition switches that are sold by most venders. I now use the pop out look alike switche with good results. Its not a pop out switch but looks sort of like one from the instrument panel side. I had similiar problems with the so called modern points set up. Another thought is, are you running a micro filter , anywhere in the fuel system ? I had similar problems with micro fuel filters. The mesh is SOOOOOOO fine that very small sediment that would run through the system without problems would partially block the filter and restrict the flow, if i feathered the throttle just right I could make it home. many things can cause similar symptoms.
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Removed pop out, jumped to coil ,and test drove,did the same thing.No micro. stock points,tried known good distributor same thing. Thanks for the thoughts.
 
Steve Plucker said:
I understand Don Diers had a good thought last Saturday at breakfast:D

Pluck
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Hello Steve! No go tho! Good breakfast tho! How about coming over and visit, maybe you have a solution(s). We will be looking forward to your visit with the new wife.Whidbey is nice! Thanks
 
Switch your coil to a known coil and make sure coil to distributor wire is all the way inserted. I had a coil that would run fine then after a few minutes driving backfire and stop. Once cooled off, would run again.
 
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