Poor mileage from 460
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Poor mileage from 460
Help,
I have a 1985 F-250 4x4, auto with a 460. I cannot seem to get better than 6-8 mpg on the highway or town. I have recently tuned it up and it runs great, but still no help in the fuel mileage. I was told to get rid of the Holley 4V carb and go with a Carter AFB.
Any suggestions or comments?
Thanks Scott
I have a 1985 F-250 4x4, auto with a 460. I cannot seem to get better than 6-8 mpg on the highway or town. I have recently tuned it up and it runs great, but still no help in the fuel mileage. I was told to get rid of the Holley 4V carb and go with a Carter AFB.
Any suggestions or comments?
Thanks Scott
New User
Joined: Jun 1999
Posts: 15
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Poor mileage from 460
>Scott, what axle ratio do you have?
>
I have to jump in here. I have an 86F250/460/auto/2WD. Milage is REAL low and its quite a problem. The truck is in great shape and I don't want to sell it. Where do I find the code for the Axel ratio?......Where do I find the designation for the carb.Weber or Carter.
I'm determined to keep this truck!!!
Gary
>
I have to jump in here. I have an 86F250/460/auto/2WD. Milage is REAL low and its quite a problem. The truck is in great shape and I don't want to sell it. Where do I find the code for the Axel ratio?......Where do I find the designation for the carb.Weber or Carter.
I'm determined to keep this truck!!!
Gary
Posting Guru
Joined: Sep 1999
Posts: 2,297
Likes: 1
From: Indiana
Poor mileage from 460
Gary, the axle code is on the drivers side by the door jam on a plastic decal. If its gone look on the rear differential cover there should be a small metal tag under one of the bolts,wire brush it off to see what it says. There will be numbers and such on it.
Posting Guru
Joined: Sep 1999
Posts: 2,297
Likes: 1
From: Indiana
Poor mileage from 460
Scott, Maybe the carb change would help. Your gears aren't to steep. It also sounds from other posts I've read about 460 mileage this may be about it. Had you checked the mileage before and it was higher?
Freshman User
Joined: Apr 2000
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Poor mileage from 460
To get significantly better mpg you will have to spend some dough. Roller rocker conversion can net 1- 1 1/2 mpg. An after market ignition designed for gas mileage like jacobs would probably help. ( if it don't you've a money back guarantee ) From here the best bet will be some type of closed-loop fuel injection system like Holley's or get the factory MPI. My friend with the same problem now gets 13mpg in his truck using the MPI. Any way you look at it you either pay through the nose for all of this and get another 5mpg or pay out for the extra gas, if prices keep going up all of it will be worth it.
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Junior User
Joined: Jul 1999
Posts: 53
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Poor mileage from 460
Scott,
The Holley is a very good carburetor and I doubt that changing will do much good. Your problem may be a ruptured power valve in the Holley that will cause serious mileage problems. If you have had any violent backfires through the carb this is probably the problem. Also, check for vacuum leaks and the float settings on your carburetor as well as the carburetor hold down bolts. Any air leaks under the carb will kill mileage. Take a can of WD-40 and spray around vacuum hoses manifold mating surfaces, etc., to see if there is a vacuum leak. The engine will speed up when you find a leak.
John
The Holley is a very good carburetor and I doubt that changing will do much good. Your problem may be a ruptured power valve in the Holley that will cause serious mileage problems. If you have had any violent backfires through the carb this is probably the problem. Also, check for vacuum leaks and the float settings on your carburetor as well as the carburetor hold down bolts. Any air leaks under the carb will kill mileage. Take a can of WD-40 and spray around vacuum hoses manifold mating surfaces, etc., to see if there is a vacuum leak. The engine will speed up when you find a leak.
John
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