loosing power and backfires

[bgalla]

My 31 has been running great until the last two times I drove it. It starts and idles great, but when I get in high gear and my speed gets up I loose power spontaneously and it backfires. The car slows down and then runs fine for a block or two and then the same thing happens. I took it out this am (cool) and the same thing happened. The fuel looks clean, not over heating. I re-timed it about a month ago and it was running fine until now. Thanks for any help Bruce

[TinCup]

Have you checked the condensor?

[bogdonj]

check condensor and also check to see if you got air leaking around the manifold.

[mass A man]

Bruce, try a search on Fordbarn's past posts on this subject. Without seeing the car, it could be MANY things associated with spark or gas problems. Is it a "backfire" from tail pipe or a loud pop from carb? That may help nail it down.

[Patrick L.]

If you slow down and just cruise at a steady lower speed is it OK ?? Does your loss of power seem to be speed related ?? Once it starts losing power and starts to backfire after the power loss if slowing down brings everything back to normal until you try to speed up again,, then,, you may be losing fuel supply.. Remove the fuel line from the carburetor and see if you have a good steady continuous stream,, then try loosening or removing the fuel cap and see if that helps..
If slowing down doesn't help then I too would look at an electrical problem such as a loose or defective condenser..

[bgalla]

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The back fire is out the tail pipe. I have not checked the condenser. It seems to happen more when there is a bigger demand on the engine. I will check for a free fuel flow. Thanks any more suggestions. Bruce

[Bruce]

Bruce,
I am in agreement with Mass A Man: Could be lots of different things. However, and or what it is worth, last time our Roadster exhibited those symptoms a gas tank filter that fits in the fuel sut-off and sticks up into the bottom of the gas tank cured the problem. I didn't figure it out for myself, somebody who had an engine backfiring and dying and fixed it tipped me off.
Now, when I run out of gas there will still be a pint left in the bottom of the tank. That will be frustrating. But I did not have to take the tank off to clean out the sediment & rust that was blocking the fuel line intake.
Try it; Cheap, easy, and you might get bragging rights.

[mass A man]

Bruce, sounds to me it could be the condenser, as the previous fellows said, or something with the spark or the pop out ig. sw. wire is shorting out sometimes, causing a backfire. I know sometimes, a so-called rebuilt pop out cable has had a new, plastic insulated wire put in place of the old original wire within the armored cable, then the heat of the engine can slowly "melt" the insulation down to the point of the conducting wire grounds out to the armored cable, sometimes intermittently, causing the engine to die for a bit, producing a loud backfire. That inner wire should have a temperature rating above what the heat is at that point.

[Mike]

Sounds like rust in the tank, when a chuck floats over the filter or gas valve it causes the car to skip like it is running out of gas.
mike

[BILL WILLIAMSON]

I've been HAWKING & HAWKING that little stainless standpipe filter that goes in the top of the gas shutoff pipe. IT'S A MUST HAVE ADDITION! Once installed and everything is cleaned thoroughly clear down to the carb, you will NEVER have chunks of crap pluggin' up stuff!
All I ever find in my carb bowl is a rust colored talcum powder lookin' stuff that never seems to cause a problem. Bill W.

[Ca. Kid]

Did you check the screen in the carburetor?

[Duffy1]

Will this work on a late 31 sw ,indented fire wall with shut off valve on engine side of F W .

Thanks

[Special Coupe Frank]

If your fuel system checks-out okay, and there are no big vacuum leaks, my next suspect would be a bad condensor.

[Tom Wesenberg]

Originally Posted by Duffy1

Will this work on a late 31 sw ,indented fire wall with shut off valve on engine side of F W .

Thanks

I've installed that little screen on a couple indented firewall tanks, and it works fine.

[Fred K-OR]

One of our club members has a spark plug that was not screwed in all the way. Caused loss of power.

[[email protected]]

Originally Posted by BILL WILLIAMSON

I've been HAWKING & HAWKING that little stainless standpipe filter that goes in the top of the gas shutoff pipe. IT'S A MUST HAVE ADDITION! Once installed and everything is cleaned thoroughly clear down to the carb, you will NEVER have chunks of crap pluggin' up stuff!
All I ever find in my carb bowl is a rust colored talcum powder lookin' stuff that never seems to cause a problem. Bill W.

Either a stand pipe filter or short length of copper pipe added to the shut off valve is a must. Get the gas intake above the rust flake sediment vibrating around in the bottom of the tank.

Once on a tour one of the cars experienced your symptoms and their Model A would sometimes quit from lack of fuel. When he took out his gas tank to have it cleaned out he found a dime sized foil seal probably off of a bottle of HEET. The tank was pretty clean otherwise. This piece of foil was acting like a flapper valve to the fuel shut off. That is also why his symtoms would come and go with no reason. A stand pipe here would have prevented this from happening.

[30ccpickup]

This is my trouble shooting cheat sheet web page. http://modelabasics.com/Roadside%20Troubleshooting.htm

Printable version http://modelabasics.com/Roadside%20T...0Model%20A.pdf

Post your fix and I will add it.

Paul

[Cool Hand Lurker]

"All I ever find in my carb bowl is a rust colored talcum powder lookin' stuff that never seems to cause a problem. Bill W. "

Bill said this was after putting in the shut-off valve filter, so it was just the fine rust still getting through.
I had the same problem with lack of power and backfiring. I cleaned out the carburetor and found this fine rust powder in the GAV valve and passage. Once I cleaned out the carb it ran a LOT better. In fact now I can just about shut off the GAV completely when running.

[jmeckel]

I had a problem like this with mine, found the problem to be the float level set wrong. Set it to proper fuel level by removing 1 gasket under the float valve and it fixed the problem. Just one more of the 100 possible fixes for this type of problem.

[jerry of whidbey]

I just went threw the the same thing changed condensers coil checked wireing and every thing else ended up retorking manafold and it worked seems when it got hot the manafold leaked air and it lost power try re torking