1984 with EEC-IV and feedback carb.
well after thinking that i should be getting better than 10mpg, i took out the ECT and found it to work perfectly. But as I check the voltage in the harness, something was clearly wrong. Both wires had 4.7v in them. Next I checked the TPS and found it to have 4.7v on its vref and ground wires. The MAP sensor has 4.7v on all three wires. The wires are good cause the computer is putting these voltages on the wires. I dont even have the EGR working cause the solinoids that control it rusted shut. Thermactor system is not working properly as it always pumps air into the cats. The only thing that works right is the ignition advance. This thing even passed Ohio's emmission check 2 yrs ago and it even had some vac leaks too.
Im considering doing the DS2 swap as $140 for a new comp is too much.
Considering all the things that are wrong, will I be able to get more mileage out of it? more power?

 

Check the junkyards, you should be able to find a computer for cheaper than that. A working factory computer will be better than a "remanufactured" one from a parts store anyway.

If you do decide to go to DS2, you'll need a new distributor, non-feedback carb, and ignition module. And you'll have to wire it up correctly. I haven't noticed any power difference between the electronic and non-electronic carbed trucks.

 

a comp in the junkyards around here is $50, also my dad has had some bad experiences with junkyard electronics. right now the comp doesnt know if im in the mountains over under the sea, running WOT or idling, or if the engine is up to operating temp. i dont even think the feedback solinoid is adjusting for optimum fuel mixture anyway. also isnt the conversion as easy as swapping the dizzy, connecting it to the module with a factory harness and splicing 2 wires to the module, and using a non feedback carb?
wouldnt i get better mileage?

 

anyother opinions

 

My opinion: Swapping to a DuraSpark system from the junk yard ($40) and installing a non-feedback Carter YF from ebay ($33) was a easier option for me than fooling around with the EEC system. The mileage increased an average of about 3MPG.

A word of caution: If your state safety/smog inspector fails you because of the removed computer and smog equipment, the DuraSpark and non-feedback carb may not end up being the best option.

 

in ohio, the emissions check is on a dyno and they put a probe in your tailpipe and drive. they dont look to see if you have cats until you fail. they dont even look under the hood. i dont think i can fail anyway, 2 yrs ago i passed with "flying colors" with no egr, smog pump pumping air to the cats full time, no power to comp, running 20* timing.
anyway, all i have is this yrs test and 2 more b4 im exempt.
FordF150Fixer-what was wrong with your comp that you got 3 more mpg?

 

It is my understanding that the EEC computer can go into a "open loop" or "limp home" mode if the computer itself fails or if the computer inputs get too far out of range. I bought a '84 that seemed to run OK on the test drive. After I had it for a while it became apparent that the gas mileage wasn't good. I got around to actually measuring the mileage and found it to be 11MPG on a good day.

Some initial testing found that there was no timing advance. I did some research and found that the TFI ignition system does not have centrifugal or vacuum advance mechanisms. In the TFI system, the timing advance is done electronically by the EEC computer. Rather than screw around with the EEC/TFI system, I went to the junk yard and picked up a DuraSpark distributor, module, and wiring harness. The DuraSpark made a noticeable improvement in power and response but not much in mileage. I was getting about 12MPG.

I reasoned that if the EEC had not been controlling the timing, it probably was not controlling the feedback carburetor properly. I got a non-feedback carb from ebay and replaced the feedback carb and the rest of the computer stuff. I now get a pretty regular 15MPG and the truck drives a LOT better.

Now that its springtime in Virginia, the next step should be to actually tune the new carburetor to see if I can improve the MPG. In any case, I found it easier to just retrofit the distributor and carb with pre-EEC units than try to troubleshoot the EEC stuff.

 

thats a nice mpg gain
anyone else done this swap?