Just purchased a 1991 F150 XLT Lariat 4.9L E4OD bone stock as far as I can tell.

Question: What are tho pros and cons to EFI?

 

That's like asking the pros & cons of a personal computer or not; a smart phone or not; cable for your TV or not: too many to list.

But if you're asking about REMOVING the EFI; then the advantage to EFI is that the truck is legal to drive on public roads & lands with it. Remove it (or tamper with anything else that affects emissions) and it won't be. Even if there's no testing or enforcement where you drive right now - laws regarding gas-burning engines are changing RAPIDLY all over the world, and it'll be really expensive to return the truck to legal later, or replace it. Much more expensive than simply maintaining it properly now.

 

Yeah, good point. Just didn’t know if it was a common thing or not..

 

Generally speaking, an EFI system has many more moving parts controlled by a computer. A carburetor system is mostly all manual set up with less moving parts. I find carburetors are easier to work with because its been around a lot longer and simplistic in nature compared to EFI. But I would venture to say a correctly set up EFI will give you more consistent results.

 

The only moving parts specific to EFI are the injectors & the IAC valve (but it'll run without that one). Carburetor engines also have a fuel pump, throttle, distributor, EGR, & secondary air system, so they're not substantially different for EFI. Obviously it's a matter of opinion, but my perception has always been that EFI is vastly simpler than carb (which relies on airflow, vacuum, counterweights, cams, screws, a bimetallic coil, exhaust heat, & many other delicate mechanisms to work). EFI relies on an oxygen sensor (HEGO), TPS, MAP, ECT, ACT, & PIP (which is part of the ignition system). 6 discrete sensors that are very easy to understand & diagnose. And they NEVER require adjustment, but the EEC re-tunes the mixture a few hundred times per second (unlike a carb that might get tuned once a decade). I can't imagine anything simpler, more-robust, or more-efficient.

 

My last truck was an 87 Chevy V10. Last year of the square body and tbi. K10 with tbi. I bought it from a flipper in a trade for an old cutlass convertible. I'm pretty sure he swapped the carbed engine and parts from an 84 chevy. It was a beautiful truck and I did a lot to it. I got a Quadrajet from a guy in cali who had worked for Jet. Thing ran like fuel injection, electronic choke. Had a tiny flat spot when she was almost warm in really cold weather. This was up north and it was -9... would fire right up.

Got 13.5 mpg regularly w a 305 but most carbed vehicles aren't nearly as refine/calibrated. Fuel injection is so much simpler and reliable over a range of temps and altitudes. I recently picked up a 87 F150 w/ 4.9. Would stall if you came to a stop but drove pretty well. Was told it was the IAC... he had thrown one in from a junk yard but it must have been bad. Had some new parts in it like the tps and plugs etc. #3 and 4 cylinders plugs were loose lol. Long story short I installed an IAC, motorcraft $62 and a 20 o2 sensor and she runs very well. Still need to pull the dash to get the warning lights etc to work, replace some hoses and bulbs etc.

Here in NC they don't inspect vehicles after 30 years. I loved that my chevy was carbed and I had fun playing around with the edelbrock it came with. Could never get it quite right... professionally built quadrajet ran like fuel injection but only within a limited altitude etc. I watched a couple youtube video's where the 4.9 was converted to carb and imho, I'd only do it if you can get the donor parts for cheap and want a project. or... you have a vehicle that is an electrical nightmare.

 

I understand what you are saying and apparently your not understanding what I am saying. I am not literally saying "moving parts" as parts that move but parts involved in keeping and engine running. The carburetor and EFI in its simplest definition is to feed fuel to the engine. A carbureted system does not require sensors, TPS, MAP, ECT, ACT, & PIP to keep and engine running. It doesn't need 6 discrete sensors that are very easy to understand and diagnose to keep and engine running, or an ECC to adjust the mixture a few hundred times per second. I also did not say that it was a superior system to the EFI. All I was saying is that it's, in my opinion, and easier system to work with. Unless of course, you're into plug and play which an EFI seems to be.

 

True: I didn't understand that, when you said "moving parts", you meant NOT moving parts. Or that you're not counting all the moving & not-moving parts of a carburetor, but you are somehow counting more EFI parts (even though it has far fewer). And you're right that a carb doesn't rely on 6 sensors - it relies on tiny jets, an accelerator pump, counterweights, cams, screws, a bimetallic coil, & many other delicate mechanisms to work. Most of the parts in this diagram move & wear (out), and require relatively precise initial & periodic adjustment:

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Most of the parts in this one (which shows more of the intake and still has fewer parts) do NOT move or wear, and NONE require adjustment:

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How could needing work be easier to work with than NOT needing any work?

Here's the vacuum map for a 300ci(4.9L) carb, and its tune-up procedure:

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Here's one typical of an EFI 4.9L:

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Of course you're entitled to your opinion, but the EFI looks simpler to me, and it clearly has fewer parts.