460 Black Smoke/ Backfire
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From: Roy, Utah
460 Black Smoke/ Backfire
I have a 89 claass A motorhome w/ John Deere Chasis/ Ford 460. I am having big problems. Symptoms include: black smoke exhaust, backfire(flame thrower nickname), carb backfire and lean pops, black carbon plugs, very rough running.I have checked the following: Carb (tried a different one that I new was good), timing, #1 cylinder at TDC, fuel filter, EGR Valve, new electronic ing. module, elec. fuel pump, and many other items.
I am at the end of my ideas. Any advise would be greatly appreciated. Anyone willing to burn it down for me can also reply
Thanks
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460 Black Smoke/ Backfire
I would guess that the power valve on the carb would be shot after a backfire. Also check your fuel pressure. Pump could only be putting out 1-3 psi instead of 4-6 causing a lean backfire. Oh, and replace the plugs with new ones and double check that no wires are crossed.
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460 Black Smoke/ Backfire
Almost forgot. If its been sitting for a while the gas would have evaporated from the fuel bowls and the needle and seat assembly could be stuck allowing constant fuel flow with no shut off. This happened on my 460. Try tapping the carb with a soft hammer. If that doesn't work, take off the fuel bowls and free the needle and seat by hand.
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From: Louisville,Ky.
460 Black Smoke/ Backfire
Double check the firing order on the plugwires. Inspect the cap for moisture/carbon tracking. Sounds like timing is too low. It could also have a vacuum leak somewhere. Fuel pressure could be too high causing the needlevalves to be blown off of the seats, which will cause flooding.
Just some suggestions. Good luck.
Just some suggestions. Good luck.
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From: Comstock
460 Black Smoke/ Backfire
The problem you are experiencing is due to the use of unleaded fuel. The valve seats have recessed into heads. You will need to have the heads replaced of repaired with hardened seats. Have done dozens of them. Big $$$$$.
Proford
Proford
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460 Black Smoke/ Backfire
>The problem you are experiencing is due to the use of
>unleaded fuel. The valve seats have recessed into heads.
>You will need to have the heads replaced of repaired with
>hardened seats. Have done dozens of them. Big $$$$$.
>
>Proford
If I'm not mistaken but the quit using leaded fuel long before his 89 460 was built. It already has hardened seats. I had a similar problem and it was the pin inside the dizzy had sheared off.
-- William (Tony) Whited
74 F350 Ranger XLT Super Camper Special 460
77 F150 Custom 460
77 F250 Custom 460 (parts truck)
El Paso, TX Semper Fi
>unleaded fuel. The valve seats have recessed into heads.
>You will need to have the heads replaced of repaired with
>hardened seats. Have done dozens of them. Big $$$$$.
>
>Proford
If I'm not mistaken but the quit using leaded fuel long before his 89 460 was built. It already has hardened seats. I had a similar problem and it was the pin inside the dizzy had sheared off.
-- William (Tony) Whited
74 F350 Ranger XLT Super Camper Special 460
77 F150 Custom 460
77 F250 Custom 460 (parts truck)
El Paso, TX Semper Fi
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New User
Joined: Apr 2002
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From: Roy, Utah
460 Black Smoke/ Backfire
>>The problem you are experiencing is due to the use of
>>unleaded fuel. The valve seats have recessed into heads.
>>You will need to have the heads replaced of repaired with
>>hardened seats. Have done dozens of them. Big $$$$$.
>>
>>Proford
>
>If I'm not mistaken but the quit using leaded fuel long
>before his 89 460 was built. It already has hardened seats.
> I had a similar problem and it was the pin inside the dizzy
>had sheared off.
>
>-- William (Tony) Whited
>74 F350 Ranger XLT Super Camper Special 460
>77 F150 Custom 460
>77 F250 Custom 460 (parts truck)
>El Paso, TX Semper Fi
>
>
Thanks for everyones help. I am trying them all. One question, What is "the dizzy"?
>>unleaded fuel. The valve seats have recessed into heads.
>>You will need to have the heads replaced of repaired with
>>hardened seats. Have done dozens of them. Big $$$$$.
>>
>>Proford
>
>If I'm not mistaken but the quit using leaded fuel long
>before his 89 460 was built. It already has hardened seats.
> I had a similar problem and it was the pin inside the dizzy
>had sheared off.
>
>-- William (Tony) Whited
>74 F350 Ranger XLT Super Camper Special 460
>77 F150 Custom 460
>77 F250 Custom 460 (parts truck)
>El Paso, TX Semper Fi
>
>
Thanks for everyones help. I am trying them all. One question, What is "the dizzy"?
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460 Black Smoke/ Backfire
distrubutor
-- William (Tony) Whited
74 F350 Ranger XLT Super Camper Special 460
77 F150 Custom 460
77 F250 Custom 460 (parts truck)
El Paso, TX Semper Fi
-- William (Tony) Whited
74 F350 Ranger XLT Super Camper Special 460
77 F150 Custom 460
77 F250 Custom 460 (parts truck)
El Paso, TX Semper Fi
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From: Comstock
460 Black Smoke/ Backfire
the john deere 460 is a dso engine and did not have the seats changed ford didn't do it until they fuel injected the motor pull the valve covers and look at valve stem heights, replace/repair heads overhaul the carb because now the power valve is blown out
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460 Black Smoke/ Backfire
[updated:LAST EDITED ON 06-May-02 AT 10:42 AM (EST)]>
>If I'm not mistaken but the quit using leaded fuel long
>before his 89 460 was built. It already has hardened seats.
> I had a similar problem and it was the pin inside the dizzy
>had sheared off.
>
>-- William (Tony) Whited
>74 F350 Ranger XLT Super Camper Special 460
>77 F150 Custom 460
>77 F250 Custom 460 (parts truck)
>El Paso, TX Semper Fi
>
>
That '89' coachmen more than likely has a '86' 460. I looked thru all my owners manuals for the subsystems on the mh, and they are all 86-87. I reckon it takes a couple of years to build the big turds. Hey luv2sled, when ya find someone to torch yers, let me park mine next to it...
Tony
>If I'm not mistaken but the quit using leaded fuel long
>before his 89 460 was built. It already has hardened seats.
> I had a similar problem and it was the pin inside the dizzy
>had sheared off.
>
>-- William (Tony) Whited
>74 F350 Ranger XLT Super Camper Special 460
>77 F150 Custom 460
>77 F250 Custom 460 (parts truck)
>El Paso, TX Semper Fi
>
>
That '89' coachmen more than likely has a '86' 460. I looked thru all my owners manuals for the subsystems on the mh, and they are all 86-87. I reckon it takes a couple of years to build the big turds. Hey luv2sled, when ya find someone to torch yers, let me park mine next to it...
Tony
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460 Black Smoke/ Backfire
[updated:LAST EDITED ON 06-May-02 AT 10:45 AM (EST)]>the john deere 460 is a dso engine and did not have the
>seats changed ford didn't do it until they fuel injected the
>motor pull the valve covers and look at valve stem heights,
>replace/repair heads overhaul the carb because now the power
>valve is blown out
hey Proford,
I know you mentioned headers as a wise investment on a mh, what head would be a good upgrade or replacement?
Tony
>seats changed ford didn't do it until they fuel injected the
>motor pull the valve covers and look at valve stem heights,
>replace/repair heads overhaul the carb because now the power
>valve is blown out
hey Proford,
I know you mentioned headers as a wise investment on a mh, what head would be a good upgrade or replacement?
Tony
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From: Roy, Utah
460 Black Smoke/ Backfire
WOW! It is finally fixed. I ended up taking it to a shop and he diagnosed a carb. rebuild, which he did, but I think it was just the EGR Plate Gasket that was lettin air in. I could have spent the $500 bucks on a new exhaust system or something useful, but at least it runs.
Thanks for everyones input.
:-staun
Thanks for everyones input.
:-staun 
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