lame 460 /F53

Thank you guys....I have driven 650 miles......ran perfect/solid...first tank 200 miles, was solid 7 MPG....after that missing started...IT was HOT and under hood temps were astronomical...in the last 6 months I have had a new ford improved pump installed , filter....I built a dual exhaust system,new ford 02 sensor, cap,rotor ford coil, ford racing 8MM wires, exhaust manifolds correct plugs,belts, fluids etc.....my scanner shows nothing, no lights, starts good runs good till hot....Has a MAJOR primary miss like a bad switch or major wire short....super surging...checked battery seen nothing...cleaned grounds....
Iam going to get tomorrow fuel pressure gage, another coil, and fuel pressure regulator.
I cannot leave this MH at a dealer overnight ....its all we have lol and will not stay in a motel.
thanks for all suggestions.

Popeye,

If we're having to guess, start by putting a fuel pressure gauge on the fuel rail. The pressures should be about 38# at idle and 42-44# at idle with the vacuum hose removed from the fuel pressure regulator. If that proves positive, then a pressure test while driving at wide open throttle is in order. That should be no less than 38#. I think you should be able to buy a fuel pressure tester for about 50 bucks at an auto parts store. If low fuel pressure then you could have a restricted fuel filter or a bad fuel pump. If the fuel pressures are ok, I suggest you test each plug wire for continuity. Approximately 1000 ohms per foot is normal. What you don't want is a plug wire that shows NO continuity. Beyond those tests, you will probably want to leave it to the professionals.
The plug wires on my 95 Bounder 460 lasted 18 years and 120,000 miles, so I suspect we are not victims of excessive under the dog house temperatures.

Richard

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What year is your Ford?

Have you checked it with a scanner? Many auto parts stores have a a scanner, and will allow you to use it in the parking lot for free..

If the anti-ping sensor is not working correctly, it can cause the engine to retard timing, making it a lame engine. Can you smell the exhaust? You should not be smelling any unburned gasoline in it. (don't suck up to much exhaust). If it smells basically clean, you can say it is.

Does the engine consume oil between changes? How many miles between adding a quart of oil? My 75 F-350 with 460 engine used a quart about every 1,000 miles. Once I rebuilt it, it used a little less. My 97 F-53 with 460" engine used less than 1 quart on a 5,500 mile trip around the country.

After rebuilding my 460 in the 75 truck, I replaced the distributor and it made a LOT more power. Like night and day, it would spin the tires with the camper on board.

Newer models have electronic controls that control the ignition timing, and have a anti-ping control, that will retard timing and enrichen the fuel mixture if it detects pinging from low quality fuels and low octane fuel. This leads to both poor mileage and reducedpower. Try a 1/2 tank of 92 octane fuel in the RV(it will only cost about $2 more than regular gas) and might improve things if you have fuel injection. With a carburator (87 and earlier) you might not see a change at all.

If one cylinder is not getting spark, or is mis-firing, you can improve this by replacing the rotor, cap, and spark plug wires. It will only cost about $30 or less. If your O2 sensor is more than 10 years old, replace that too. It is about $75, but can cause a engine to not work properly.

Fred.

Before you spend money getting scans, maybe a bit of old-fashioned trouble shooting would help. The 460 is notorious for high under-hood temperatures which fry the plug wires. New plug wires would be my first recommendation, along with a replacement distributor cap and rotor arm. Maybe new spark plugs would also help.

I've heard tales from friends at Ford that the exhaust manifolds can glow bright red (around 1800 degrees F) when climbing grades at low speeds on wide throttle openings.

I had an '85 Class C with that POS engine, with enough smog gear to run a cruise ship. It's best used as a boat anchor! I was never so happy to sell a vehicle as that one, despite taking a major bath. We could get temps on the passenger side of the insulated doghouse high enough to melt DW's tennis shoe soles.

I can't believe Ford got away with selling such a dangerous vehicle.