4.9 carb problem
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Freshman User
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4.9 carb problem
i just put a 4.9 out of a 1986 f150 into my 1985 f150 . i can get it to start on starting fluid for a second . i have gas at the carb but none coming out of the jet(from what i can see) but i think i found the problem, there is a solinoid under the carb that i'm believing turns the fuel off, i have no idea what its called and does it turn the fuel off. the motor ran a week ago before i pulled it but i dont have the same harness in my truck , to wire the solinoid up. i dont have a wiring diagram to figure out how to wire it up. the wires are orange,black and green. any help would be helpful
Lead Driver
Joined: Jul 2009
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From: Sheffield, AL
Welcome to the forum, tnfarmer67!
There are other members much better qualified to assist you regarding electric issues, but I can tell you that the years 1984-1986 had the "feedback" computer controlled carburetor, so at least you are working in the correct year range.
There are other members much better qualified to assist you regarding electric issues, but I can tell you that the years 1984-1986 had the "feedback" computer controlled carburetor, so at least you are working in the correct year range.
Elder User
Joined: Apr 2003
Posts: 673
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From: Maryland
IIRC the "feedback" carb has electrical connections for choke, throttle position sensor and fuel enrichment solenoid. It does not have a fuel on/off solenoid. Look for fuel with the engine off and manually working the throttle; you should see the accelerator pump shot enter the venturi. If no fuel there, work backwards: fuel filter, fuel pump, tank selector switch etc. Do a search, these carbs have been pretty well covered in this forum. I would start by tapping on the carb with the handle of a large screwdriver or similar item, you may have a stuck float...
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i had fuel to the carb and none coming out of the jets while looking own the barrell. i changed the carb to a earlier model (1981) and it fired right up and runs good. so all i have to do is splice some wires together for the alternator and then to the muffler shop on a trailer of course.
Lead Driver
Joined: Jul 2009
Posts: 6,477
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From: Sheffield, AL
tnfarmer67,
The "feedback" system was controlled by the computer. The computer also controls the ignition timing. If your truck still has the original distributor, the computer will "sense" that the carburetor signals are missing and will place the timing in the "safe mode", which locks the timing at something like 6 or 8 degrees BTDC. For best performance [and fuel mileage], you will want to read about Duraspark 2 conversion. Use the search button at the top of the page... there are many posts covering this topic. I have done this very thing and am well pleased.
The "feedback" system was controlled by the computer. The computer also controls the ignition timing. If your truck still has the original distributor, the computer will "sense" that the carburetor signals are missing and will place the timing in the "safe mode", which locks the timing at something like 6 or 8 degrees BTDC. For best performance [and fuel mileage], you will want to read about Duraspark 2 conversion. Use the search button at the top of the page... there are many posts covering this topic. I have done this very thing and am well pleased.
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i have a duraspark dist. in it and a 4 pin gm (hei) ignition module that i learned from in another thread. had exhaust put on today cost me 100.00 and its running rough but i need to adjust the distributor.
