1993 bronco engine swap to carburation
 

hey guys i want to take out my 5.0 efi engine and swap it with an older 302 or 351 carburated. how hard will this be? is there any engines that i could use my same tranny for?

This rather tedious and awkward concept has been discussed at great length in the past. Its a waste of time and effort to make the truck less fuel efficient, more difficult to troubleshoot problems and less reliable overall.

However, if you are going to go backwards 20-30 years with the technology you will have to pull the E4OD (fully electronic transmission) as well or buy/install a stand-alone shift controller for it. The E4OD will NOT function without the EEC-IV computer in place and functioning nor will it work if the VSS is not functioning. The VSS gives its information to the EEC-IV computer and gets its reference voltage from it as well. Keep in mind that removing the EEC-IV ignition and engine control system will also render the speedometer/odometer inoperable unless you only disconnect all of the under-hood sensors and control devices and leave the EEC-IV computer connected and operational. You will have a perpetual "check engine" light on the dash unless you remove the lamp because all of the devices that the computer monitors/controls on/in the engine will be gone.

If you still want to continue and don't feel like investing in a stand-alone shift controller for the E4OD, you can always drop a C6 into it and lose the overdrive capability or an AOD which will require all of the necessary linkage and throttle valve cable to make it shift properly. Oh yeah, and that linkage has to be compatible with which ever carburetor you decide to install. On the up side, the AOD will keep the overdrive. However, no matter which transmission you swap in place of the E4OD you WILL have to have driveshaft lengths modified. The E4OD is by-far the largest transmission ever used in these trucks.

Why? That's a serious question too, what do you hope to gain from this?

i considered doing this to my 300 inline 6 because the emissions systems are rusted away, and i thought sticking a 4 barrel on it i could get more power and overall the fuel system would be simpler, (no computer, no huge EFI intake, no miles of wires, no high pressure fuel pump)

ive just decided to clean up under the hood by taking the smog pump out (useless, tubes are gone) and remove the rail, plug all the holes with bolts. clean everything up and paint the intake to make it look a little nicer

also i occasionally go off roading and if i went on a steep slope it wouldnt run right with a carb.

and in the winter id rather have EFI than a carb...

How often do you plan to replace fouled O2 sensors? Loss of the air injection at startup leaves the fuel/air ratio ultra rich and will choke O2 sensors in a hurry. Loss of air injection to the OEM catalytic converter renders it useless. On top of that, the rich condition will eventually clog the cat... and clog it faster if its not heating properly. It simply will NOT reach the necessary operating temperature without the air injection.

Just making it clear for anyone reading this thread what arbitrarily removing emissions components will do to their vehicles. Just because its not there and the computer will compensate well enough that you don't notice the difference while driving, doesn't mean damage isn't being done.

I agree with the above. I see no reason to go back to a carbed engine. Unless you like getting worse gas mileage, and having less HP and torque. Not too mention cold starts in winter with a carb.

Jim

ok i see what you mean by keeping the efi. i just wanted something that is alot easier to work on. ive been learning alot about them but still not enough to know what is wrong when something is acting up. and the whole gas mileage is what i dont get. im getting terrible gas mileage and my engine is running bad, and theres for sure not as much power as i should have. ive tried pulling codes and it doesnt even throw me any. so i just wanted something thats gonna be easier for me for now.

That's why the EEC-IV produces fault Codes that are easily checked and troubleshot. EEC-IV Code readers run about $20 retail and if you absolutely have to, you can pull Codes with a short piece of wire or a paperclip. If you need to know what the Codes mean when you get them, check this page out. If you need to know how to actually go about fixing a specific fault Code, post the Codes here and we can detail the procedures for dealing with them and interpret which Codes are the problem children and which are probably there because of some other Code. As with anything else, once you have dealt with it for a while, you will be well-versed enough to troubleshoot without much outside input.

ok i see. what i did was run a wire from the self input tester to the negative terminal on the battery, turn the truck to the on position, and then start counting codes. is this correct?

That will work. You don't need to run it that far though. Just jump from the STI (Self Test Initiation) connector (single female) to the ground terminal on the DLC (Data Link Connector). If you are looking at the DLC with the row of two terminals at the top and the row of four terminals at the bottom, the ground is the right-hand terminal in the upper row of two. The image is on the linked page in my previous post.

One thing to make absolutely certain of BEFORE administering either the KOEO (Key On Engine Off) or the KOER (Key On Engine Running) test is that you run the engine PRIOR to administering either test so it is at operating temperature when you do run the tests. If you don't, you will get all sorts of odd fault Codes that won't be accurate.

Always keep in mind too that the first CEL flashes indicate the engine size by flashing out either four times for a V8 or three times for the 300 L6. Codes will either be two-digit OR three-digit. You will NEVER get both from the ECM... always one or the other depending upon the vintage of the ECM.

Codes flash out in succession with a two-second pause between digits and four seconds between Codes.