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Hi all,
I recently picked up a $1,400 F150 4x4 with a fresh 300/NP435 in it to haul my BMW's(Bike and Car!) back to Colorado. Long story short, I'm aware of this dreaded feedback system and do plan to convert to DS2 and do a mild towing build.
However, upon looking over my truck I've noticed that there is ZERO electrical connectivity to the Carburetor whatsoever. The oxygen sensor is present but unplugged, no signs of the female connection anywhere. There is no wiring coming from the carburetor. Terrible vacuum leak at the intake manifold to top it all off.
It's gotta run like crap right? Because it's a feedback system with an electronic advance and sensors communicating with a computer. WRONG! The truck runs GREAT! Pulls smooth and strong through the power and, can do 95 on the highway without a problem(In Mexico..)
Exhaust has no foul odor. I just don't get it. However, the choke plate seems to be seized in the vertical position but still pretty easily.
So what gives, big six enthusiasts? Am I missing something or is there some sort of hybrid TFI/Non-Feedback system I dont know about? Did the previous owner do some haggard work that somehow works well?
Awhite, you forgot 1 vary important part of the information you provided. ....THE YEAR!
Take a picture of the distributor so we can see it too.
For all we know the truck is pre feed back and all you have to do is a good tune up.
Dave - - - -
Gentlemen, my sincere apologies! The truck is an '84. The first year of the feedback as I understand. I'll have to snap a picture of the dizzy tomorrow when. I have some light but it is absolutely a TFI system. No vacuum advance here. There is a HACKED TF UP wiring harness coming from the firewall.
A pressing question I have- my choke plate seems to be as seized as seized gets. Can't move it to save my life. The old truck still fires right up, cold as cold can be. I just don't understand. Is this normal or black magic?
If you have the TFI distributor, then you don't have any advance on the distributor aside from mechanical. Your engine will run just fine, but you won't be getting the added benefits that advancing adds, such as gas mileage. Getting a proper DSII distributor in there that operates off of vacuum will still help.
As for the choke being stuck open, where are you located? If it's nice and warm out, you probably won't notice much, but when it gets down below freezing, I highly doubt you'll be able to start it up!
Here's the current ignition and (butchered)wiring setup. I've also got a cold start video if that'd be of any interest, of the truck starting in 50* range after sitting all night. I'm in NC unfortunately, so it doesn't get TOO cold. I believe I might have issues as it gets colder, but I'm just impressed that this truck fires up and runs so well without any of its "essential" feedback.
Question- Id like to purchase the DS2 setup new, and can piece together the Distributor, Coil, ICM, and Plug Wires from RockAuto for about $100ish. I can buy the American Autowire, harness from SR for $103. If this mystery YFA is indeed a non-feedback model, that should be all I need, correct?
That first picture of the carb & stud see anything funny anout it?
Remove that threaded stud and see if the choke works.
As for the d I s t. Yet needs to be upgraded to A DS2 or HEI dist. Some guys have had good luck with them. For more information head over to the 80-86 truck area as there is a lot of information there on the swap.
Dave - - - -
The stud was removed, I couldn't stop laughing when I saw it, however it wasn't the cause for the seized choke. The shaft was gummed up for whatever the reason and took some carb cleaner and PB blaster to free it up.
I dialed it in and reconnected the 6v wire to the choke but I think I've got some linkage missing or broken somewhere because I cannot get the high idle cam to l do what it needs to do. Does anybody have a picture of the choke setup on what I believe to be an '80-'83 YFA looks like?
I hope to get out to the garage tomorrow and can get a few pictures of mine (81).
I think it works as I only had the motor running long enough for a short road test and then after a set of plugs to see if a miss was fixed and it was....then I took the whole truck apart!
Dave ----
...I dialed it in and reconnected the 6v wire to the choke but I think I've got some linkage missing or broken somewhere because I cannot get the high idle cam to l do what it needs to do. Does anybody have a picture of the choke setup on what I believe to be an '80-'83 YFA looks like?
It is not uncommon for the small counterweight that pulls the choke linkage open to corrode and seize up. Remove the shoulder screw that holds it in place, clean it and the counterweight and reassemble with silicon spray lube.
Here is a picture of my carb choke linkage side.
If you need more let me know but I think as said on checking the weight and what you said freed the choke the carb needs a good cleaning and lube for it to work right.
Dave ----
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