Cold Weather Rich Condition
FTE Legend
Joined: Nov 2015
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From: Angier, NC
The DUI is simply a beefed up HEI that's tailored to fit different engines. So, parts are interchangeable. I'll do a test on the coil to see if anything's out of sorts.
As for the on/off nature, it doesn't really go back and forth. It's generally starts in about 20 - 30 seconds after first firing up, and then will go away after 10 - 15 minutes of driving (about 5 - 10 minutes after the temp gauge has reached operating temperature). And it's invariably after it returns to idle (like at a stoplight).
One thing I did notice this morning, back on the carb icing thing, is that the transition slots were filled with frost. Could this be the cause?
As for the on/off nature, it doesn't really go back and forth. It's generally starts in about 20 - 30 seconds after first firing up, and then will go away after 10 - 15 minutes of driving (about 5 - 10 minutes after the temp gauge has reached operating temperature). And it's invariably after it returns to idle (like at a stoplight).
One thing I did notice this morning, back on the carb icing thing, is that the transition slots were filled with frost. Could this be the cause?
The issue goes away when the engine bay heats up enough to keep the carb from icing up.
You can also get icing when temp & dew point is just right and does not have to be below freezing.
To over come the icing you need to heat the incoming air like a stock air filter assy does, nothing else will stop the icing.
Dave ----
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Joined: Dec 2007
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From: Boise, Idaho
Yeah, I understand that you have to actually have warm air going into the carb to reduce/eliminate carb icing. I just want to be sure that's actually what my problem is. The only icing I see is a little white frost in the transition slots. There's no ice buildup or other symptoms that I regularly read about or have seen pictures of.
However, those slots are so thin that I could see frost in them jacking up all the metering.
I just want to be sure that's it before I dismiss it, since if it is, there's not a ton I can do about it without a lot of fab work (which I don't really have the setup for).
However, those slots are so thin that I could see frost in them jacking up all the metering.
I just want to be sure that's it before I dismiss it, since if it is, there's not a ton I can do about it without a lot of fab work (which I don't really have the setup for).
Lead Driver
Joined: Jul 2009
Posts: 6,477
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From: Sheffield, AL
Justin, do you know anyone who has a Ford with 4 barrel and stock air cleaner [truck or car]? If so, ask to borrow the air cleaner and try it out. Just run a section of the metallic 2" hose, available at auto parts stores, to the vicinity of the exhaust and tie it there. It will draw up the heated air.
Cargo Master
Joined: Dec 2004
Posts: 3,362
Likes: 22
From: Florence, SC
I am with FuzzFace. I think it is carburetor icing. A stock thermostatic air cleaner should fix the problem. Not only does it prevent carburetor icing, it also keeps the air/fuel mixture more consistent year round, which means seasonal carburetor adjustments and/or jet changes are eliminated.
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Joined: Dec 2007
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From: Boise, Idaho
I haven't. Once it warmed up through the summer, I completely forgot about it, to be honest. 
I haven't noticed it resurfacing though, and we've had some pretty good 20° days. Granted, I imagine it's a mix of humidity with the cold that causes it, which we haven't had yet.
Guess we'll see.
I haven't noticed it resurfacing though, and we've had some pretty good 20° days. Granted, I imagine it's a mix of humidity with the cold that causes it, which we haven't had yet.
Guess we'll see.
FTE Legend
Joined: Nov 2015
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From: Angier, NC
I haven't. Once it warmed up through the summer, I completely forgot about it, to be honest.
I haven't noticed it resurfacing though, and we've had some pretty good 20° days. Granted, I imagine it's a mix of humidity with the cold that causes it, which we haven't had yet.
Guess we'll see.
I haven't noticed it resurfacing though, and we've had some pretty good 20° days. Granted, I imagine it's a mix of humidity with the cold that causes it, which we haven't had yet.
Guess we'll see.
As said any 2v or 4v ford filter should fit the carb. Use it during winter then switch for summer.
Dave ----
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Cargo Master
Joined: Dec 2004
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From: Florence, SC
Why would you switch for the summer? With the ducts hooked up, it would be a true "cold air" intake system, unlike sucking in hot underhood air from an open-element style air cleaner. A thermostatic air cleaner is a necessary item a carbureted vehicle needs in order to match the driveability of a modern vehicle with EFI.
If you are using an Offenhauser intake and a 4V on your six, I don't *think* any of the thermostatic air cleaners will clear.
I tried to use my stock air cleaner from my Motorcraft 2150 2V and it wouldn't fit over the Autolite 4100 4V I am using.
FTE Legend
Joined: Nov 2015
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From: Angier, NC
It was for the Bronco guy that is running an open air filter now that if he wanted to run the open filter during the summer but you are right.
One of the reasons I am running the stock filter but I am also running the stock 1v carb.
Dave ----
One of the reasons I am running the stock filter but I am also running the stock 1v carb.
Dave ----
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