CFI to carb conversion

July 06, 2005, 03:15:31 AM

Since I looked around a lot for a good detailed description of how to do the swap, and the one one Jason's site was rather sketchy, I thought I would provide my own version of the events :

For a 1985 Ford 302 you will need the following:

- electric low-pressure fuel pump
- 2bbl carburetor
- new carb gasket, preferably the hardened plastic/metal type
- points distributor (mine came from an '85 Bronco)
- spark plug wires

First, I dropped the tank. The two bolts that hold the metal strips are a pain in the ass to take off, so be sure to use a lot of WD-40 on them, it will make your work a lot easier. It might be a good idea to get a buddy to help you with dropping the tank, if you don't want to end up stuck under the car holding it up with your knees. I had my friend hold the driver's side up, since the passenger side was held by the inlet tube. By the way, it's always a good idea to have as little gas as possible in the tank whenever you drop it.

Then you need to take off the little bracket that holds the inlet pipe flush into the tank, so you can slide the tank to the driver's side and off of the pipe. Again, I strongly recommend having as little gas as possible, otherwise you too will have to go and change your pants, like my buddy had to after getting sloshed.

Before you slide the tank off, make sure you have disconnected the wiring and the hoses. After you have set the tank down, remove the locking plate using a hammer and a screw driver, and pull out the old pump. Take it off, and then in its place clamp a piece of hose long enough that it will go down to the bottom of the tank. You also need to weigh the end of the hose down with something (I used a nut) so it will not float up afterwards when you fill it up.Do not mess with the return line, you will still need it. Snip off the wires that were connected to the pump, you will not need them anymore.

Reassemble everything, don't forget to put the locking plate back on, put the tank back on the car, reconnecting all the hoses and the fuel gauge wires, but do NOT reconnect the pump wires. In fact you can even cut them off where they split from the loom.

If the pump you bought has its own filter, like mine did, you can go this way : Remove the old fuel filter, it's located under and behind the passenger-side door. In its place, install the new pump, and tighten it down. Now more than likely your old connections will not fit properly, so you will need to fabricate new connections from the fuel line to the pump. I used two short pieces of metal tubing, two short lengths of rubber hose and four hose clamps. You will also need to get power to the pump. Originally the pump was controlled by the EEC, and I wanted to get rid of that, so I just ran a wire from the coil to the pump through one of the holes in the wheel well, alongside the fuel lines.

Take off the CFI, EGR and whatnot until you have nothing but the manifold and the four screws. Now if you are not changing manifolds as well, this is where the hardened gasket comes in. The carburetor (I used a rebuilt Motorcraft) will probably come with its own gasket, but that might not be enough to keep exhaust gasses from escaping through the EGR port on the passenger side, which is what happened to me.
After putting the bigger one in, I got rid of that problem.

Next you will want to connect the fuel lines to the carb. You could probably do without a return line, but I'd rather be sure that the pump doesn't burn out, so I used a T pipe to connect the feed and the return, and the other outlet was connected to the carb.
You will need to get another piece of hose and connect the PCV valve on top of your driver's side valve cover to the back of the carb, otherwise you'll see smoke coming out of the breather on the passenger side.

Get the distributor from any salvage yard, I paid $30 for mine, it's from an '85 Bronco, just make sure it's a points distributor and the vacuum advance works (suck on it, the arm should move). Before taking off the old distributor make a note of which way it's pointing, and plug in the new one in approximately the same position, the closer the better. With regard to the timing, all I can say is I had my friend do it for me, I have no idea what to do besides turning the distributor clockwise-counterclockwise.
You will now need new spark-plug wires, and I would suggest a new rotor and cap as well, just to make sure things are fine. If you want to go the whole nine yards, get the points and the spark plugs.

Connect the vacuum hoses to the carb, and run a vacuum line from the carb to the distributor. Connect the throttle to the carb. Connect the transmission TV rod to the carb, you might have to fab some parts for it to work properly if it's not designed for an AOD. Mine just snapped on but I still had to get it adjusted. There are a number of guides out there on how to do it, I ended up having to get it done at a shop.

As far as I can recall, that's about it, hope it helps.

Re: CFI to carb conversion

Reply #1 – July 06, 2005, 05:23:10 PM

Wow, that makes more sense than all the others I read. I had actually thought about running a mechanical fuel pump for a while. Maybe I will swap in the carbed 84 HO after all.

Re: CFI to carb conversion

Reply #2 – July 11, 2005, 12:29:45 AM

Good work on that write up.

There is another good post on CrownVic.net about the same conversion, pretty lengthy but might be good for those who are researching.

2-Door Carb Conversion is Alive - AOD

Re: CFI to carb conversion

Reply #3 – July 11, 2005, 02:21:31 AM

I smell a sticky! It'll be much easier to refer to this than to link people to Jason Fletcher's every time.

CFI to carb conversion

Reply #4 – October 18, 2005, 09:55:58 AM

bump. had a friend from another forum who was looking for something like this. perhaps jcassity could add it to his general car work topic.

CFI to carb conversion

Reply #5 – October 18, 2005, 10:48:32 AM

Quote from: siscrew

You will also need to get power to the pump. Originally the pump was controlled by the EEC, and I wanted to get rid of that, so I just ran a wire from the coil to the pump through one of the holes in the wheel well, alongside the fuel lines.

Only Problem i have with the write-up fuel pumps should never be ran off the coil. Find a 12v source off the ignition and isolate it away from the coil.