Fuel Injection to Carburetor

[skeef2012]

Hey all;

I am doing a frame up restoration on a 1981 Bronco with a 302 Fuel Injected Engine. When I had the machining work done on the engine block I told the shop that I wanted a performance cam and planned to put a 4BBL in it. I am now at the point where I am starting to put the engine back together and am having second thoughts about going with the carburetor. Has anyone done this before and does it make sense? My biggest concern is the what I am going to need to do to the EEC in order to make it work along with everything else it does. I understand that I need an adapter for the AOD TV cable but that seems pretty simple. Am I being an idiot in attempting this or should I go back to fuel injection? Thanks in advance for all your opinions.

 

[Rons beast]

Hey Skeef, welcome

If you go with the carb, you might as well abandon the EEC. It can't regulate fuel with the carb, and unless you like to drive and look at a CE light, the comp will always be thinking something is wrong.

Why change anyway? The FI can work with a bigger cam, and would still get you better fuel mileage. Depending how radical the cam, it may need no other programing, or modification.

Besides, if you go to a carb, you're not restoring...you're rebuilding.

Good Luck

 

[skeef2012]

Hey Skeef, welcome

If you go with the carb, you might as well abandon the EEC. It can't regulate fuel with the carb, and unless you like to drive and look at a CE light, the comp will always be thinking something is wrong.

Why change anyway? The FI can work with a bigger cam, and would still get you better fuel mileage. Depending how radical the cam, it may need no other programing, or modification.

Besides, if you go to a carb, you're not restoring...you're rebuilding.

Good Luck

Thanks for that information and opinion. Good point about the rebuild versus restore. My thoughts regarding the cam and carb was really more vanity than functionality. I know with the carb and cam I could produce some of that low idle muscle car chatter which I thought at the time would be cool. The Bronco is for my son and will be a daily driver so in retrospect it might not be the best choice.

Follow up question....Given I stay with the fuel injection, is there a resource that I can go to that can give me recommendations on what combination of cam and programming I will need to do to make it all work? I don't mind having to reprogram as long as it's something that can be done easily. I'd like to be able to make a tradeoff between HP, Gas Mileage, etc etc so I don't choose something I will regret after the fact. Thanks again!

 

[Rons beast]

First decide on the cam. Then the programing can follow.

Sounds like you want something just above the stock camming. I like Comp Cams, and on the Summit site, they give all the info on what cam works in what RPM range. Broncs are fairly heavy, and need more oomph at the bottom end.

I would look for something that works in the 1200-3500 rpm range or close to that. After all you don't want your son getting more horses at 5K do you?

After you choose a cam, you can look for a programer that will allow you to tune accordingly.

I have a guy in my neighborhood that will reprogram most any car for a fee. It could be cheeper than buying a programmer. OR...you could be that guy and grab some extra bucks.

Another thought ...you could just go with a new fuel program, and forget the cam....but you wouldn't get the exhaust note you want. Remember it doesn't matter if you have Fi or a carb. the exhaust note is gonna be from the cam and exhaust system.

Good Luck

 

[skeef2012]

First decide on the cam. Then the programing can follow.

Sounds like you want something just above the stock camming. I like Comp Cams, and on the Summit site, they give all the info on what cam works in what RPM range. Broncs are fairly heavy, and need more oomph at the bottom end.

I would look for something that works in the 1200-3500 rpm range or close to that. After all you don't want your son getting more horses at 5K do you?

After you choose a cam, you can look for a programer that will allow you to tune accordingly.

I have a guy in my neighborhood that will reprogram most any car for a fee. It could be cheeper than buying a programmer. OR...you could be that guy and grab some extra bucks.

Another thought ...you could just go with a new fuel program, and forget the cam....but you wouldn't get the exhaust note you want. Remember it doesn't matter if you have Fi or a carb. the exhaust note is gonna be from the cam and exhaust system.

Good Luck

Thanks again for your help!

 

[miesk5]

yo,

Sorry for coming in late.

Carburetor & C6 Conversion to EFI/OBD II & EO4D in an 86

Source: by Kurt H at http://2bigbroncos.net//technical/EFI_OBDII_Conversion/index.html

EFI Swap to Carburetor; "...It's actually a pretty simple swap. Basically all of the computer/sensor stuff can be scrapped. You won't need any of it. What you will need...a carb (obviously), a new intake manifold, a new distributor, an ignition control box (like an MSD or Mallory box...I've had good luck with MSD 6A boxes so long as they're not exposed to significant heat), and a carb fuel pump. The EFI pump is way too strong for a carb so you'll need something like a Holley carb electric pump. The ignition stuff is pretty straight forward, but for a working tach you'll need to find the tach wire in the ignition wiring harness and attach it to the positive side of your coil. I know in Mustangs this wire was green with a yellow tracer. It may be the same in your Bronco, but it's good to double check. For a carb I would use something like a Holley 600cfm double pumper or a slightly smaller Carter carb. I had a 625cfm Carter on my Mustang before I switched over to a turbo'ed EFI setup and it was a little too much for the motor. One point worth stating is that if you have an automatic transmission that has overdrive (like an AOD), you'll need an adapter for the TV linkage on the transmission since AODs never came on carbed motors. One is (or at least used to be) available for Holley carbs through Sacramento Mustang, but they retail for just under $100. If you have a 3 speed like a C4 then all you'll need to do is make sure the carb has a kickdown linkage. Mind you I got my old Carter to work with my AOD...but I think that was just sheer luck. Hope this helps...let me know if there's anything else I can clear up for you..."

http://en.allexperts.com/q/Ford-Repair-811/1988-Bronco-302-efi.htm

EFI Swap to Carburetor Compilation

Source: by Seabronc, BLADE262US & Justshootme84 via miesk5 at Ford Bronco Zone Forums http://broncozone.com/topic/22129-88-bronco-efi-to-carb/

EFI Swap Using a “High-Output” Engine PCM with a non-** Engine Camshaft; "...Fir

Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=92