Too Fat
New User
Joined: Dec 2002
Posts: 7
Likes: 0
From: ROCK HILL USA
Too Fat
I just purchased a 68 F150.
I was told that the 390 was out of Mustang (possibly 390 GT)
or Fairlane GT as per a local ford collector.
It has a problem of running rich and fouling plugs ater 2 tanks of fuel.I'm sure I have done a good tune-up with plugs,points,condensor,wires.Rebuilt carb(650 Holley w/vac sec).
it still fouls plugs though.
There isn't any smoke ,it starts easy,and it runs good until the plugs foul.
It has an Ford Alum intake ,headers,C6 w/shift kit,3.70 Traction lock.
Does anyone have any ideas why this is happening?
I was told that the 390 was out of Mustang (possibly 390 GT)
or Fairlane GT as per a local ford collector.
It has a problem of running rich and fouling plugs ater 2 tanks of fuel.I'm sure I have done a good tune-up with plugs,points,condensor,wires.Rebuilt carb(650 Holley w/vac sec).
it still fouls plugs though.
There isn't any smoke ,it starts easy,and it runs good until the plugs foul.
It has an Ford Alum intake ,headers,C6 w/shift kit,3.70 Traction lock.
Does anyone have any ideas why this is happening?
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Too Fat
You may want to look towards your ignition system. Mine was the same way for a while. The spark just wasn't good enough when the engine was cold and it would foul the plugs on startup. Get an MSD coil and replace the points with a pertronix unit. When you are posting please do not type in all caps. It is hard to read that way. Welcome to FTE!!!
Logistics Pro
Joined: Feb 2000
Posts: 3,565
Likes: 9
From: Sun River St. George
Too Fat
Rat! Couple of things make me ask about the cam. Someone has been in the engine and it is not the correct one for this truck. The “Ford collector” comment sounds like a Dealer blowing smoke! The engine runs fine after tune up and for a considerable distance (two tanks of fuel). Engine idle is smooth and no complaints about miss fire. He has changed the carburetor without any change in engine performance. A camshaft set to far advanced or retarded forces an excessively rich mixture which fouls the plugs. Other things could cause this problem, clogged air cleaner, lack of manifold heat, cold wet climate and more. But Shortrange is comfortable around engines and does his own tune ups. I think he has already checked the obvious and going deep is the next step. I would be interested to see cranking vacuum, running vacuum and cranking compression. Easier would be to peek at the timing chain (bet you a nickel it’s set advanced).
William in Atlanta
William in Atlanta
New User
Joined: Dec 2002
Posts: 7
Likes: 0
From: ROCK HILL USA
Too Fat
william, thanks for the reply and you moght have something on the cam timing, i have tried settint the timing with a light (10degree, dist vac unhooked) then with a vac guage, had to move the dist quit a bit to get the eng vac to reach normal vac reading, when driving it pinged a lot , might be a good ideal to check the chain?
Trending Topics
Elder User
Joined: May 2002
Posts: 799
Likes: 0
Too Fat
Make sure the vacuum and mechanical advance are working, too.
1972 F250 Custom Sport Camper Special 4x2 360 2v C6 3.73
Some day hope to shorten to a 104" wheelbase as part of a Broncification project
My FTE Website -- http://www.clubfte.com/users/mlf72f250/index.html
My Galleries -- https://www.ford-trucks.com/user_gallery/displaygallery.php?userid=1108
1972 F250 Custom Sport Camper Special 4x2 360 2v C6 3.73
Some day hope to shorten to a 104" wheelbase as part of a Broncification project
My FTE Website -- http://www.clubfte.com/users/mlf72f250/index.html
My Galleries -- https://www.ford-trucks.com/user_gallery/displaygallery.php?userid=1108
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Elder User
Joined: Mar 2002
Posts: 609
Likes: 0
From: Watauga TEXAS
Too Fat
[updated:LAST EDITED ON 14-Dec-02 AT 00:51 AM (EST)]>william, thanks for the reply and you moght have something
>on the cam timing, i have tried settint the timing with a
>light (10degree, dist vac unhooked) then with a vac guage,
>had to move the dist quit a bit to get the eng vac to reach
>normal vac reading, when driving it pinged a lot , might be
>a good ideal to check the chain?
Just a note- The timing you set with a light is ignition timing. Cam timing and Ignition timing are two different things.
Joe
>on the cam timing, i have tried settint the timing with a
>light (10degree, dist vac unhooked) then with a vac guage,
>had to move the dist quit a bit to get the eng vac to reach
>normal vac reading, when driving it pinged a lot , might be
>a good ideal to check the chain?
Just a note- The timing you set with a light is ignition timing. Cam timing and Ignition timing are two different things.
Joe
Thread
Thread Starter
Forum
Replies
Last Post
