Converting from throttle body injection to carborator

i have an 85 buick century, is it possible to convert it from throttle body injection to a regular carborator?

where can i find fuel system diagrams and specifications.

is the injection system coupled with the ignition module or are they seperate?

would this conversion interfer with proper ignition timing?

Nope! Can’t do it. you have to maintain the emission components that originally came on a vehicle for that model year. This includes the fuel injection system. Besides, the amount of money you would spend to do this would be more than the vehicle is worth. And it wouldn’t run right afterwards anyway.


If carburetors were better than fuel injection, cars would still come with carburetors. In addition, today’s mechanics have little experience working with carburetors, and even the old timers have probably forgotten more about carburetion than they’d care to admit.

TBI (aka SPFI) was a fairly lame stop-gap technology, but even a TBI system was more effective at regulating emissions than a carburetor could ever hope to be.

If you’re having problems with the car, find someone who knows that they’re doing and have them fix it, rather than try to cobble together an even worse solution.

I think I remember seeing a television program on the Speed Channel, perhaps “Two Guys Garage” where an engine was converted from fuel injection to a carburetor. This was for racing purposes and the conversion probably wouldn’t be legal for street use because it wouldn’t pass emission tests.

IMHO, carburetors are more complicated than fuel injection in many ways. The only carburetor I rebuilt was on a 1950 Chevrolet pick-up truck that I bought for $110 in the early 1970’s. This was a one barrel carburetor with a manual choke. I spent a whole afternoon at the task. I didn’t do something right the first time and had to tear it apart the second time and start all over. I still own a 1978 Oldsmobile Cutlass 4-4-2 that has a carburetor. I had trouble for the past year and would have to prime the engine to get it started if it sat more than a day. Even with a service manual, I was afraid to tackle rebuilding the carburetor. The shop that services my other vehicles looked at the car and suggested that the carburetor needed to be replaced. This would run at least $400–more than the car is worth. I was puzzled, because even if the wells in the carburetor were leaking, I thought that the fuel pump should be able to pump enough fuel that the car would eventually start. I finally found an old mechanic that was willing to work on the carburetor. He found that the problem wasn’t the carburetor at all, but a section of neoprene fuel line at the gas tank that had deteriorated to the point that it was sucking air. A new 6" piece of fuel hose solved my problem. As others have suggested, even good present day mechanics don’t understand carburetors.

If you are going racing, which doesn’t seem likely with a 1985 Buick Century, then you will want to be able to set the timing according to the way you set up the carburetor. If you think you are getting out of problems with the throttle body injection, I think you are opening yourself up to all other kinds of problems.

Unfortunately, there isn’t as much you can do to cars made in the 1980’s and later to change things around. Back in 1992, I took the 1978 Oldmobile to an old mechanic the specialized in tune-ups. He worked on my car for a couple of hours–my son was going to be driving back and forth to the northern part of the state for a job in the car. The price this mechanic charged was way too low. When I asked him about the price, he replied, “I love working on these old cars because you can do something with them”. If you want a carbureted engine, you will have to go back a decade or more before 1985.

Was wondering… Why in the world would you want to? The fuel injection (even as crappy as they were in 85’) is still likely to be better than a carburetor. You’ll get better performance, mileage, and cleaner emissions with the FI.