Conversion? EFI to Carb

865.0 · Jul 8, 2006

Whats needed to convert an Fox EFI Mustang to carburetor power?

What's recommended for a mostly stock 5.0 with an E-cam?

Daily driver with 3.73 gears and a T-5.

Thanks

5ive.oh · Jul 8, 2006

Stay with the EFI, it's better on fuel and more driveable than a carb setup. But all it takes is a new intake and a carb, low pressure fuel pump, and a bit of messing with the vacuum lines. Of course the EEC IV will hate you.

http://www.jason.fletcher.net/tech/efi-carb/efi-carb.htm

R2D2 · Jul 8, 2006

5ive.oh said:
Stay with the EFI, it's better on fuel and more driveable than a carb setup. But all it takes is a new intake and a carb, low pressure fuel pump, and a bit of messing with the vacuum lines. Of course the EEC IV will hate you.

http://www.jason.fletcher.net/tech/efi-carb/efi-carb.htm

Until your one of the dozens upon dozens of efi problem threads

5ive.oh · Jul 8, 2006

But if it ain't broke, don't fix it.

R2D2 · Jul 8, 2006

5ive.oh said:
But if it ain't broke, don't fix it.

oh there always broke, read a few forums.

jrichker · Jul 8, 2006

Once again, why?
Carbs are great for the track and make good power. For a strip only N/A car, they are hard to beat. Step on the pedal and flush - it's a gasoline toilet!

EFI RULES on the street for a car that is driven in all kinds of weather, up and down mountains and gets great gas mileage. EFI will make just as much power as a carb and be easier to drive on the street. If isn't hard to tune if you know what you are doing.

There isn't a carb made without computer assist that can do all those things as well as EFI can. The only possible exception would be the IDA or DCOE Webers which cost major $$$ - like $3000 for 4 each IDA 48's and a manifold.

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst: ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...ra charge. See [url]http://www.amazonhose.com for more information.

While you are at the electrical part, you'll need a Durspark or similar ignition system. The EFI ignition depends on the EFI sensors to advance the spark. Rip out the TPS and MAP/Baro sensors and the computer will have no idea of the proper ignition timing for best performance. Running a fixed timing setting is only for test purposes or for a race track only car. Don't try it on the street: the results will not be nearly as good as a properly setup Durspark or equal. Crane makes a really nice distributor for non-EFI applications. . See http://www.cranecams.com/index.php?show=browseParts&lvl=4&prt=127 for more information.

vristang · Jul 8, 2006

sbftech said:
oh there always broke, read a few forums.

I get the feeling that you are trying to say that Ford EFI (EEC-IV in our case), has reliability issues.
I think you may be putting the blame for lack of maintenance on the Ford Engineer.

In my experience the stock efi setup is great.
If you are going to work on it yourself, you will need to take the time to learn more about the system.
The book by Probst, posted by JR above, is excellent for getting into the basics of the EDC-IV.
There is much more detailed info out there, but start with that book.

Since this is daily driven, avoid the carb.
EFI will provide better results.
To help show the dependabilty and flexibility of the EEC-IV...
The 408w in my sig was daily driven. I never had any issues, until I started losing compression.

jason

R2D2 · Jul 8, 2006

you guys crack me up, people act like carbs cant be on a daily driver While your figuring out your koeo codes, surging idles, replacing this sesor, that sensor, chasing gremlins I continue to drive right on by. Ya you get 3mpg better, big deal, I will trade that any day. To each his own

88 Fox GT · Jul 8, 2006

sbftech said:
you guys crack me up, people act like carbs cant be on a daily driver While your figuring out your koeo codes, surging idles, replacing this sesor, that sensor, chasing gremlins I continue to drive right on by. Ya you get 3mpg better, big deal, I will trade that any day. To each his own

I don't have any problems with my EFI. For some, it's just too technical for them to work on. For me, it's very simple stuff really.

5ive.oh · Jul 8, 2006

I think it's a generalization that EFI is more reliable. My thoughts is that it was done for emissions sake. My 86 is sporting a holley 650 and I drive it all the time. I would rather tune my carb then pull codes or replace injectors anyday.

jrichker · Jul 8, 2006

I seriously doubt that there are more than a handful of people here that can accurately & completely explain how many flow circuits are in a carb and how they work. Simplicity is an illusion...

vristang · Jul 8, 2006

You crack me up.

I've had gremlins show up on a carb car as well. That is not specific to either setup.

Many people see the computer as an obstacle in diagnosing.
This just shows that they don't fully understand how the system works, yet.
The computer is a major help in diagnosing most efi issues.
By the way a decent code reader will pull codes in 1-2 minutes.
Just plug it in, and wait.

We could go back and forth like this forever though.

vristang · Jul 8, 2006

jrichker said:
I seriously doubt that there are more than a handful of people here that can accurately & completely explain how many flow circuits are in a carb and how they work. Simplicity is an illusion...

AGREED

My dad is doing a carb swap on a mid 80s GMC right now.
Even with the diagrams from the factory book
AND
the diagrams from the new carb
it is still not completely clear how all the vac lines should be routed.

I think alot of guys that run carbs, also cut several other systems as well.
No EGR for example.

865.0 · Jul 8, 2006

Thanks for the recommendations.

I run EFI on my stang and love it. I don't have many mods so I never played with the computer or much of anything other than a Mass Air Conversion, TB replacment, etc.

My brother has a 4-cyl/5.0 conversion. The car has a erractic idle to have just a E303 cam and jerks when you let off the pedal. Let's not talk about the Gas fumes. Obviously there is a problem with fuel enrichment or the lack of it.

I've had similar problems with my car in the past and a can of brake cleaner and a cotton swab fixed the problem. I just cleaned the element in my MAM. Every now and then it still jerks a little when I left off the pedal. I blame it on the absence of a bypass for the supercharger.

Back to the EFI/Carb. The reason for the swap is just basically simplicity. Everything on the car is old, wires, injectors, TB, intake. The only thing new is a MAM, fuel pressure regulator, and fuel pump.

After reading the replies, it may not be such a simple task.

I was just wanting to weigh the costs to fix the EFI or switch over. Money is always an issue as well as MPG these days.

LEE93COBRA · Jul 8, 2006

jrichker said:
Once again, why?
Carbs are great for the track and make good power. For a strip only N/A car, they are hard to beat. Step on the pedal and flush - it's a gasoline toilet!

EFI RULES on the street for a car that is driven in all kinds of weather, up and down mountains and gets great gas mileage. EFI will make just as much power as a carb and be easier to drive on the street. If isn't hard to tune if you know what you are doing.

There isn't a carb made without computer assist that can do all those things as well as EFI can. The only possible exception would be the IDA or DCOE Webers which cost major $$$ - like $3000 for 4 each IDA 48's and a manifold.

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst: ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...ra charge. See [url]http://www.amazonhose.com for more information.

While you are at the electrical part, you'll need a Durspark or similar ignition system. The EFI ignition depends on the EFI sensors to advance the spark. Rip out the TPS and MAP/Baro sensors and the computer will have no idea of the proper ignition timing for best performance. Running a fixed timing setting is only for test purposes or for a race track only car. Don't try it on the street: the results will not be nearly as good as a properly setup Durspark or equal. Crane makes a really nice distributor for non-EFI applications. . See http://www.cranecams.com/index.php?show=browseParts&lvl=4&prt=127 for more information.

+1.

Not to mention that when you throw a carb on OEM EFI stang it kills the value of it (and yes that includes 4cyl/5.0 conversion cars) Nobody wants a carb car!

90mustangGT · Jul 8, 2006

Leave it EFI when your near stock, but on heavily modded cars, the price to keep EFI is by far unreasonable.

Cost of a stand-alone engine managment (when the stock computer's capabilities become out of range) will be somewhere in the $1300-1800.

Big injectors are expensive, along with the other fuel components.

The excessive tuning required is unreasonable.

One sensor goes wrong, the whole engine can go boom.

Carbs are simple, cheaper, and when set up right tend to run better. Carb cars do tend to make more power.

Carb cars can get good milege, it's all in the setup.

Often, people don't set them up right. How often do you hear of people putting a 750 on a 302?

Why do they call tuners, tuners... and why do they hog dyno shops and always have graphs instead of timeslips? because they are constantly tuning, and on the dyno while the hotrodders are out racing.

Either setup car run well, but it determines how much time and money you have.

LEE93COBRA · Jul 8, 2006

90mustangGT said:
Carbs are simple, cheaper, and when set up right tend to run better. Carb cars do tend to make more power. .

90mustangGT said:
Why do they call tuners, tuners... and why do they hog dyno shops and always have graphs instead of timeslips? because they are constantly tuning, and on the dyno while the hotrodders are out racing.
.

For people like me who want 20+mpg with a/c and 500-600 rwhp.

billison · Jul 8, 2006

try out my world for a few, i have a 85 cfi "center fuel inj" it has less power than a carb and less econ than efi, talk about crap, i'd give my best friends right arm for carb stuff, i'm broke

dastang2 · Jul 8, 2006

who says people don't wants carburetors. i do in fact. and that is why i have one. no BS harnesses and sensors. plus i can have the topend off the engine in 30-40 minutes. try that with efi.

795.0pacecar · Jul 8, 2006

Carbs do not generally make more power than EFI, the best of the best produce similar numbers, tourqe in the favor of the EFI car most of the time. When one sensor goes the whole thing doesn't crap out, the computer substitues the sensors values for stored information.

www.fordfuelinjection.com said:
The question always come up: why fuel injection, and why Ford’s fuel injection?
But most answers start debates and holy wars, so lets look at a realistic factual answer. Performance: The stock 5.0L engine produced 250HP/300ft/lbs, and still passed emission testing. Cost: Ford EFI systems can be had at 1/3 the cost of aftermarket EFI systems. Peace of mind: not many fathers buy undependable cars for their daughters, so why should you drive one? Many people claim they can rebuild a carb on the side of the road. Current EFI engines can run 100,000 miles before needing a tune ups. Technology: Ford is leading other manufacturers in EFI technology development; they have spent millions of dollars making sure this was the ideal system. No other system in its class has its capabilities. It can operate upside-down, even if your oil pump can’t. It will never suffer from vapor lock. Hundreds of aftermarket vendors have products available for Ford’s EFI, and your closest parts stores have parts and support in stock. Understand I didn’t say it’s the best in the world, but it can be proven better than most.

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