I still stand behind what I wrote. Tweezer isn't for everyone, support is everything, there's a reason why guys step up to the $1500-2k, standalone level and have zero regrets. Getting control is step one, then you need injectors, a performance intake that doesn't exist for the inline, there's a couple obstacles with a performance inline engine, that are easily resolved going carb, that the v8 world doesn't deal with. Doable but $$$ involved. But if someone wants to screw around with a tweezer or quarter horse, more power to them.

But I'll agree, efi is the way to go if stock, theres only a couple vacum lines and sensors on these old engines, about as basic as it gets, only surpassed by the old tbi.

 

Thanks for all the information guys. Right now its not running at all. I tore it down to the frame, removed rust and bad parts and rebuilt it. New CAB, BED, Fenders, upgrading the interior etc.. Right now all my eltric seems to be working, everything interior, Lights, radio, battery (new), coil (new)... I have replaced my EEC Relay, and the EEC computer, and I get power in all locations but I have constant power on the tan/Green line (and I shouldn't) I am getting power out to the inertia switch but I believe I ave an issue in the wiring comin in/out of the EEC. I am trying to figute it out but it is frustrating.... I just want my truck running so I can use it....so the carb was an option...

 

I usually don't get into the middle of such a spirited argument but I say, let the carbs be installed!

I have a reason to say that, too. Every state looks to The People's Republic of Kalifornistan for ideas. Smog testing is slowly coming to your town and it's inevitable. When this happens, there will be a ton of Gen 9 trucks to use as spare parts for mine.

More to the point; Carburetors are so old school it's not funny. Learn to work on your EFI. Amaze your friends with your skills at setting the TPS voltage. It never hurts to get outside your comfort zone and learn something. Both of my daughters can work on EFI.

That, or I'll be there with bells on when you make that CL listing for a Gen 9 truck that needs an OEM EFI system reinstalled to pass smog. That will happen.

 

If you learn EFI on these trucks it's basically "so easy a caveman can do it mode." There's 5 or so sensors that are completely needed for the truck to run, three types of signals, four or five types of sensors and one basic type of actuator all packaged in different ways in different places to do the same job. You can pull codes with a paperclip. If you're feeling fancy you can wire up a switch instead of a paperclip. Learning how the EFI on these trucks work will give you the basic knowledge you need to work on EFI up through the mid 2000s.

 

Hey guys thanks for all the good input. I have decided to do the swap. This is my project/fun truck and I hate wiring. I can do carbs easy and once its done it will be something I can work on easily. With some TLC she'll run well. Plus I am working in my yard, my current house doesn't have a garage so weather hampers working on it and I don't have anywhere to just take it apart and let things lay around. I also have a sourse that says he can give me weverything I need. So all that said, I think I know the parts I need and the issues as well. I will need the Intake manifold, Carb, Distibutor, an Ignition module, and (if I can get it) the wiring harness for under the hood. The issues are I will need to make a Throttle cable bracket, (unless I can find one) the gear at the bottom of the distributor will need replaced, and the fuel pump I a, npt sure about. I have read that I can use th in tank Low Pressure pump, remove the Hi Pressure pump on the rail, and use a return line (albeit larger) to get good flow. If I can put all that in, then I just need to wire the electricity into the ECM correctly. I can remove the EEC and the EFI harness. anyone see any major issues?

 

Still seems like a huge waste of time to me. All that effort chasing parts, removing components, hacking up your wiring. What do you get? About 30 horsepower less, and harder cold starts.

I really don't even follow what you mean by you "have power all the time on the tan/green line"

The tan/green wire I see is the fuel pump relay control circuit on your truck, and the way that circuit is wired, you should always see 12 volts on the tan/green wire unless the truck is running. The computer grounds the tan/green wire to turn the relay on. With the relay off, the tan/green wire will read 12 volts.

The wiring for your truck is simple.

 

Unless you're converting to points ignition, you'll need something to control the distributor. Not sure if this is an oversight on your part but y'all need something, a stand-alone controller to make the coil fire.

Also, you might need to do some rewiring of the gauges to get them to work without the ECM. I've never intentionally mangled an EFI truck like this so I'm not sure how the truck will act w/o a computer.

Y'all really sure ya want to do this?

 

Well, after 3 months and 4 pages of posts, it would seem so.

I still find it amusing that anyone would be looking for benefits from a carb conversion, but if the individual opinion is that you prefer a carburetor and you are willing to overlook all the problems and live with the degraded performance, have at it.

There is enough info in the preceding posts to cover what must be done. I see the intent is stated in post #50 that the EFI wiring is to be removed. That will expose you to a lot of wiring that you will wish you never saw and it's going to be your own fault. Best to leave the wiring in place. It will make restoring the EFI much easier in the future..

An 87 truck only uses the ECU for engine functions. The rest of the truck will work just fine without the EFI, including the gauges. Possible exception for the tachometer, if equipped, but this can be worked around.

I will predict by the time you have this completed, you will have learned enough about the EFI that you will wish you would have kept it.

 

Think he has that covered, duraspark ignition module, is the controller.

To make life easier, wiring wise, I'd opt for an aftermarket ford 300 HEI distributor, plus it's cleaner, as your coil and ignition module are contained within the cap. There's also some belief that the HEI performance is better, anecdotally, based on having compared both (in new condition) back to back, I agree.

With the right fuel pressure regulator, you can use almost any OE electric fuel pump.

The major advantage to the efi 300 isn't that it's efi, it's the long runner intake, and combustion chamber shape. As the camshafts were the same for all years, and the head ports were just as restrictive.

 

Have you been reading this post? If you prefer EFI to carburetors that is absolutely fine by me. But, why do you insist on spreading false information about carburetors?

WHERE did you come up with "...about 30 horsepower less?"

WHAT makes you think carburetors have "harder cold starts?"

And the same goes for you. Why do you think so low of carburetors?

What specific "problems" are you referring to?

Why exactly, do you feel performance will be "degraded?"

True! I am glad somebody here actually knows what they are talking about.

If you take that same engine and replace the EFI components with an Offenhouser intake manifold, a Holley 390 4V carburetor, and a DuraSpark or Pertronix ignition system, you should, at the very least, match the output of the original EFI.

 

dang,you really like it old school.here's a pic of my 429 for ya.





that said,i wouldn't want to convert a modern EFI system back to carb.EFI is superior in every way.there's good reasons we've moved forward.there's nothing really any better for nostalgia in an old car.putting a modern setup in an old car is just as wrong to me too but there's no way in hell anyone could convince me to rip out the EFI system in a truck for an old carb setup.nope lol.

 

Nice engine, FORDF250HDXLT!

I am personally not a fan of an open element air cleaner, unless you use your vehicle for racing. That style of air cleaner is a BIG reason why so many people blame carburetors for running "rough" in cold weather. The stock thermostatic air cleaner is a much better design for a daily driver or a street vehicle, as it provides heated air when the engine is cold and cooler air when the engine is warmed up. This improves drivability and performance. For some reason, people like to discard these in favor of the open-element air cleaners and then wonder why their carbureted vehicle doesn't run as well or ices up in cold or humid weather.

I don't get why so many people have an old car that ran reliably with a carburetor for decades, and then replace it with an expensive aftermarket EFI system with a LOT of wiring that only gets you right back to where you were. Or in some cases, even less. I personally wouldn't convert from EFI to carburetor either. But, I also would not convert from a carburetor to EFI. But that is neither here nor there. The original poster wants to do it, and he is a GROWN MAN who already knows about carburetors. So what is the problem?

My only problem is when people start saying things about carburetors that simply isn't true. These people often make a big deal of how "simple" EFI is, yet *dismiss* the simplicity of a carburetor because they don't really understand them. All other things being equal, the reality is carburetors can be just as reliable or more as EFI, can get just as good performance or better than EFI, and can start just as good or better than EFI.

 

Well, I could ask the same of you. Why do you think so highly of carburetors? And what makes you think I think low of carburetors? I will admit to preferring EFI, but I am in no rush to convert my carb equipped vehicles to EFI and in fact would strongly resist doing so to some period correct vehicles that I am quite fond of.

Well, the installation will certainly not be straightforward. If you have been following along, you know there are issues with the necessary redesign of your fuel system. There may be emissions testing issues in the future. In this specific case, the OP wanted to remove the EFI wiring. Not a particularly easy task with the 87 wiring harness layout, (nor is it necessary for a carb swap). It's going to hurt the pocketbook. Priced a carb and manifold lately?
The majority of these proposed swaps stem from the false impression that carbs are simpler, more reliable, and better suited to performance. There is no evidence to support that. Making a carb match EFI performance can be done, but it is a difficult and demanding task. Similar effort into an EFI system will also yield spectacular results. Swapping OEM EFI for an OEM or similar carburetor system on something like an 87 300 six will result in a drop in performance. If there is any direct problem, I would say it is the starting and driveability issues associated with the choke and warmup time of the carbureted engine. If you are doing anything more than turning the key to start the engine, it has become more complex and less driveable than what we have become used to with EFI. Not to say that the issues make the vehicle undriveable, just that you must learn to deal with them

That would depend on proper tuning of the new intake system. Yes, it would be possible to match the performance, possibly even exceed under the right circumstances, but at what cost? Again, pour those dollars into tuning an EFI system and you will be miles ahead!

Lariat 85, you seem to be a pretty intelligent fellow, but you are reading way too much into this carb vs. EFI issue. The OP asked for benefits, which probably are zero, yet he still decided to go carb and that is his choice.

 

Go look at Ford's official power ratings. If he puts on stock 300 carb equipment (which it sounds like he is), he will be sacrificing anywhere between 25 to 44 HP depending on what year the carb components come from. The increase compression of the EFI 4.9 will make up somewhat for it, but not terribly much so.
Years of experience with carb'd vehicles. Yeah, I could spend 5 hours of my time getting it tuned just right so it sort of starts well at -10*F in the middle of winter and only needs 10 pumps instead of 30 to start, but then it won't be right come summer when its 90*F out. Or I could just keep it EFI, where I don't have to touch a single thing, and it will start and run great from 110*F at sea level to a -20*F winter night 12,000 feet up in the mountains.

Because unless he shells out $$$ for the aftermarket intake and carb, he will lose power.

Then if you do buy the offy intake and Holley carb, congrats. You just spent near $600 on parts to get the same power you had with the EFI system and you still don't have the same all-around driveability.

 

Carburetors have worked great for MANY years, and work great even now. That being said, I don't think carburetors are better than EFI. If you read my posts from the very beginning of this thread, you will see that I stated that several times. All I am doing is setting the record straight when some people here have been stating FALSE information regarding carburetors. I have seen more than one person here claim that carburetors have hard starting problems, Lead Head pulled a number out of thin air and said a person would lose "30 horsepower" if they converted to a carburetor (will a person gain 30 horsepower by swapping a carburetor for EFI?), and even you claimed "degraded performance" when one swaps an EFI system for a carburetor.

As you know, all of this is simply not true.

I agree with this.


I agree with this.

Not necessarily. Why are you issuing a blanket statement that swapping to a carburetor will result in a drop in performance? With the proper size carburetor, intake manifold, and proper tuning, you would be wrong.

I agree with you about EFI being simpler to start than a carburetor in that the operator only has to turn the key to start the engine. There is no getting around the fact that a carburetor needs to have a working choke in order to start up quickly and remain running under all weather conditions.

A daily driver equipped with a carburetor should only require one single pump of the pedal to set the choke and the vehicle should immediately fire. As soon as it fires, you should be able to drive away immediately without any hesitations or stalling. A warm engine doesn't even need that. A warm engine should start right up with only a turn of the key just as fast or even faster than EFI. Anything less than that and there is a problem. NOT with the design, but something is either defective or not tuned correctly.


I agree with this.

I heard someone once say that the only thing an EFI system does is trade the choke and manual tuning required for a carburetor for lots of wiring and electronic engine sensors to achieve the same result. While crude, there is some truth to that from a performance standpoint.