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Dieseljunky2, Diesel & Gas Mechanic
Category: RV
Satisfied Customers: 3946
Experience:  RV and heavy truck repairshop, ASE, Cummins, & Ford Certified
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I recently purchased a 1984/1985 Ford chassis RV (Mobile Traveler)

Resolved Question:

I recently purchased a 1984/1985 Ford chassis RV (Mobile Traveler) with a 460 7.5L engine with about 58,000 miles that gets 5.08 miles per gallon based on 200 miles of my own (sensible) driving. Can this be improved upon and if so how?

The RV had problems when I first bought it with fuel delivery that was corrected by replacing an in-tank (Airtex) fuel pump. In the process of diagnosing the problem, my mechanic also rebuilt the carburetor, rewired and replaced a valve switch for a two-tank system and installed an additional auxiliary in-line fuel pump with a mechanical switch to turn it on/off at will. The rear fuel tank continues to be a problem so it is not being used. I pump regular gas and carry no additional weight nor tow anything with it. The tire pressure is to specs. I have no records of the maintenance/service so I don't know if it has ever had a tuneup but it seems to run well and has plenty of power. Please advise.
Submitted: 7 years ago.
Category: RV
Expert:  Dieseljunky2 replied 7 years ago.

Hello, Due to the age and lack of maintanence records, a full tuneup would be recommended. More than likely, it has many hours of idle time that is not accounted for in mileage. Replace the sparkplugs, but pay special attention to the distributor cap, ignition rotor, and sparkplug wires. These deteriorate over time, and though functional, may not be at optimum operating condition. Another item of concern, would be carbon build up. An induction flush service, would most likely be beneficial to your engine's efficiency as well. Thanks

Customer: replied 7 years ago.
how much improvement can I expect over the 5 MPG that I am getting if I follow your advice?
Expert:  Dieseljunky2 replied 7 years ago.
Most of our local customers say that their RV's get arout 6.5-7.5 mpg with the 460 engine. Actual mpg, will be affected by your rear axle ratio, exhaust system, and aerodynamics of the RV.
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