|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
08-24-2021, 01:52 PM | #1 |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Roadster Backfiring
I know this has been discussed a bunch of times. I’ve read through many of the related threads but have not found a solution.
I rewired my roadster including the ignition. I also installed new plugs (gapped). Now it backfires really bad when I let off the throttle and going downhill under load. It didn't do this before. What can I do to fix this? What should I check? |
08-24-2021, 02:23 PM | #2 |
Senior Member
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 1,371
|
Re: Roadster Backfiring
Does it backfire through the carb or the muffler?
__________________
"The more things change, the more they stay the same." |
Sponsored Links (Register now to hide all advertisements) |
|
08-24-2021, 03:41 PM | #3 |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
|
08-24-2021, 03:47 PM | #4 |
Senior Member
Join Date: Jun 2014
Location: Land of Lincoln
Posts: 3,137
|
Re: Roadster Backfiring
GAV adjusted to lean, intake leaking, carburetor float set to low
__________________
Don't force it with a little hammer tap, tap, tap get a bigger hammer tap done |
08-24-2021, 03:51 PM | #5 |
Senior Member
Join Date: May 2013
Location: Along the Red River, Texas
Posts: 360
|
Re: Roadster Backfiring
I am new to the A, and got lots of advice on where to set the Gav. Also was trying to improve my mpg. When I closed the Gav too much she would backfire every time I got off the foot feed.
Sounds like you have the same problem. Try opening the Gav. And see what happens. |
08-24-2021, 04:23 PM | #6 | |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
Sponsored Links (Register now to hide all advertisements)
Quote:
|
|
08-24-2021, 04:31 PM | #7 |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
Also, I don’t understand why that would be different now when all I have done was replace plugs and wiring.
|
08-24-2021, 04:34 PM | #8 |
Senior Member
Join Date: May 2010
Posts: 319
|
Re: Roadster Backfiring
How old is the gas?
|
08-24-2021, 04:41 PM | #9 |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
|
08-24-2021, 04:50 PM | #10 | |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
Quote:
|
|
08-24-2021, 05:06 PM | #11 |
Senior Member
Join Date: Oct 2014
Location: Central New Jersey
Posts: 417
|
Re: Roadster Backfiring
You go to this thread post #4 and you start there... Get a carb rebuild by BUllock and then you have solved 99% fuel problems...
https://www.fordbarn.com/forum/showt...hlight=bullock I have a rebuilt Bullock carb, GAV (oh the mystery GAV) is turned out about 1/2 and NEVER touched. My car did all sorts of crap before I got a real carb rebuilt by this guy... GAV, and all the rest are BS after the carb is restored to new.... they were made to run....I can't say enough about the difference in starting and running since my carb by Bullock. Last edited by jg61hawk; 08-24-2021 at 05:12 PM. |
08-24-2021, 05:13 PM | #12 | |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
Quote:
|
|
08-24-2021, 05:37 PM | #13 |
Senior Member
|
Re: Roadster Backfiring
Make sure you don’t have an intake leak at manifold and carb flange. Make sure. Sometimes hard to find.
|
08-24-2021, 07:14 PM | #14 |
Senior Member
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,512
|
Re: Roadster Backfiring
All the symptoms of a leak in the intake tract somewhere. Something that hasn't been mentioned is the rotor button. They are known to track to earth and you can't see where. Try a known good one. Also check you are not getting the infamous Model A no 3/4 cross fire.
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood. |
08-24-2021, 07:48 PM | #15 |
Junior Member
Join Date: Jan 2021
Posts: 25
|
Re: Roadster Backfiring
So I just drove it with the GAV open almost an extra full turn and it didn't backfire. I'm trying to make logic from that. Why would running richer be better? Why would running leaner cause backfire.
|
08-24-2021, 08:33 PM | #16 |
Senior Member
Join Date: Jan 2012
Location: Western North Carolina
Posts: 3,936
|
Re: Roadster Backfiring
Nothing you did to the electrical caused the problem. The two are unrelated. You need to clean out the carburetor.
Lean will cause the backfiring. A jet or passage that is partially blocked in the carburetor will cause it to be lean. Opening the GAV will compensate for the blocked jet or passage.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 08-24-2021 at 08:45 PM. |
08-24-2021, 08:42 PM | #17 |
Senior Member
Join Date: Jan 2012
Location: Western North Carolina
Posts: 3,936
|
Re: Roadster Backfiring
i think the backfiring when lean is because the combustion is not complete. Any combustion that does take place is hotter. So fuel and oxygen are pumped out into the exhaust system and ignite.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
08-25-2021, 02:47 AM | #18 |
Senior Member
Join Date: Jul 2010
Location: United Kingdom
Posts: 1,445
|
Re: Roadster Backfiring
sorry wrong post.
Last edited by johnbuckley; 08-25-2021 at 02:57 AM. |
08-25-2021, 12:51 PM | #19 |
Senior Member
Join Date: May 2016
Location: Scottsdale, Arizona
Posts: 617
|
Re: Roadster Backfiring
Good Morning...You might also have a condenser that is starting to go bad. They do this when they are about done...Get a good one (more expensive) the really cheep ones are not any good...Ernie in Arizona
|
|
|
Sponsored Links (Register now to hide all advertisements) |
|