Motorcraft Feedback Carb

[rowdyb2]

Can the OE carburetor on the 2.8 function properly with out the computer? i have had a hard time tuning this carb and still cant manage to get it to run right.

 

[dangerranger83]

It functions best with the computer, designed to have it. If it comes down to it duraspark it so that you can use a non feed back carb. The factory ones are hard to tune in my dad and I had to adjust his a week ago and its running better now and the milage is a bit better.

 

[Big Jim M]

Jeep 4.2 engines had that carb for several years. What we did was to wait till the engine was cold and then start it.. which would put the variable pin in the rich position.
Then we would quickly cut it off and take the lectric plug off of it.
Then we would dig out the hi-speed adjustments and when the engine was warm we would adjust for best running and after that they worked pretty well.
Most of us simply installed an older motorcraft carb and were done with it..
If any of these things are done to the carb, the computer still controls the dist advance.
so it is a MUST to also modify the dist.
In the Jeep we just routed the wires from the sparkbox directly to the dist and left the computer out of the loop. As I remember the FOMOCO dist wires in the Jeep were purple and another was orange..
Big JIm

 

[enginepaul]

Big Jim is correct. The computer needs the entire system to operate properly, but it can be made to run without changing the distributor - but you will be running in a limp home mode and performance won't be vary good. In other words, you will need the DuraSpark if you don't use all components that go with the computer.
Check the Tech Library for a carburetor modification that replaces the stock air valve (leans the carb) located on the back of the stock carb. (you will save money on the carb, but would still need the DuraSpark to run well.)

 

[martin]

If you install a manual metering block on the carb and tune it. Leave the mixture control that you took off connected to the harness. that should prevent the computer going into limp mode which will leave the computer controlling the spark advance. I ran mine like that for a few years until I changed to a duraspark distributor and ripped out all the computer crap.