Something someone said about most of these feedback carbs being a mid-year '84 thingmade me pause. Is this one? Tag says truck was made in Dec '83, and it has the square ig module, square coil, wires under the carb., and a smog box ( I think).

Also, one of the harnesses to the... (vacuum relays?) is disconnected and looks like it was unused.

Thanks to y'all, she has no issues at all running. Idles at 600 and starts on the second crank everytime.







Ignition stuff - dirty....but functional. Have changed leaky valve cover gasket.



Someone I.D.'d this for me a while back but that file in my brain is corrupted....Smog box?

 

Whoops here's the unused harness. AC,maybe? His buddies are plugged in right behind here

 

I know my 1980 carter doesn't have any of that stuff on it, nor does my distributor. My 1982 (R.I.P.) didn't either.

 

Thanks. I need to prepare for a DS2 conversion i guess, in case the computer dies. Nice (channel?) cat in your avatar by the way.

 

Yup, feedback. I had dealt for an 84 also but hadn't looked, stopped in today and checked, it is also. But I found carbs listed with and without for 84 so not sure if some were non-feedback. I have a Duraspark II dist but looking for a non feedback carb. I will keep the coil and feed it with a GM HEI module.

 

Thanks willowbilly, it was your thread that clued me in to the potential issues. is the actual computer somewhere in the firewall like I think I have seen in later models?

 

I am not sure where the 300 six computers were located. I do know the very first 302 efi truck computers were mounted on the inside firewall right above the center tranny hump area. I would look there for yours first.

You will find that the distributor you have now looks exactly like a dist that would be found on a fuel injected Ford. You have a very early version of the EECIV computer system.

 

Some were under the drivers seat

 

Yes, that is a feedback carburetor with TFI ignition and EEC-IV computer. This was the final step in carburetor technology. The EEC-IV computer controls ignition timing, smog components, and manipulates the air/fuel mixture at the carburetor. As a result, this system is more precise and efficient than older or conventional vehicles with carburetors.

The EEC-IV computer is located inside the cab, under the dashboard and to the left of the ashtray. That gang of wires stuffed in the firewall grommet (last picture) leads right to it. I am not sure what that open plug connects to.

The electrical device that is bolted to the carburetor in the first picture is the mixture control solenoid. This is how the engine computer manipulates the air/fuel mixture at the carburetor.

The electrical device that is attached to the carburetor with a rubber hose (parallel with the fuel filter) is the bowl vent solenoid valve. This valve closes when the engine is running and opens when the engine is off. The open valve allows fuel vapors from the carburetor to be routed to the charcoal canister, which is what you called the "smog box" in picture 4. The charcoal canister stores fuel vapors from the carburetor and fuel tank until the engine is started again. When conditions are right, those fuel vapors are sucked back into the engine and burned in the intake. Both of these items are part of the evaporative emissions system.


It is rare for the engine computer to go bad. There is nothing wrong with the system you have now as long as all of the components are there and functioning. That means, do not do a carburetor conversion or any other modifications. Do not try to "clean up your engine" by eliminating things. In other words, treat it as if it were a modern engine with EFI. As long as you keep it original, your truck will continue to run great; no need for a DS2 conversion.

 

Lately, I have been driving my son's 1984 with functioning feedback system to and from work, since he is out of the country. The following is a record of gas mileage:

12/14/17 191.4 miles / 11.323 gal. = 16.90 mpg [25-70F; work]
12/15/17 91.3 miles / 4.925 gal. = 18.53 mpg [hwy @ 45-55 mph; 31-50F]
12/16/17 101.7 miles / 5.027 gal. = 20.23 mpg [hwy @ 45-65 mph; 30-55F]
12/23/17 155.4 miles / 9.011 gal. = 17.25 mpg [45-68F; work]
1/11/18 199.0 miles / 12.176 gal. = 16.34 mpg [25-62F; work w/ extended idle]

 

When they work, they aren't bad, just can be a pain to get running right when the truck gets some age on it. It looks like you averaged around 17, about the same as a non feedback.

 

Thanks all -

17 is pretty impressive. I am getting about 13 MPG around town, not too shabby, she did a bit better on her one big trip to get a flareside bed. I learned about the module overheat right before getting home lol. I was able to catch her in gear at a crowded light and limp home 15 miles by revving the gas as needed.

I am VERY glad to hear that I should be OK as long as I don't start poking her with a stick.