From EFI to carb'd on an 89

I think it would be a good idea to change the fuel lines since your efi lines are for high psi to get the flow. Carb is low psi so the lines need to be larger to flow the amount of fuel you need.

you need to get a different thortle cable.

any chance u wanna sale ur engine harness? or maybe trade for something

Go here first...

http://www.jason.fletcher.net/


What is your budget, and ill help you out the best i can.. im about done with my swap in my 1991 lx all im lacking is motivation and time.

do you plan on a manual or electric fuel pump
Get the lokar universal throttle cable (ill get you the part number tomorrow, i have it at home)
youll need to either use a duraspark ignition or get an msd dizzy and 6al ... theres alot of variables.

do you know anything about carbs? if not, but a good book on them first.

also, what are / will you engine mods be?

I just replied to another post about the same thing here are the parts I thought of plus a couple I forgot the 1st time (all of this stuff is middle of the road stuff, you can spend a lot more money if you try):
carb manifold -160
carb- 380
distributor- 200
MSD 6al- 220
carb fuel pump- 120
carb fuel pressure regulator- 50
fuel lines and fittings(braided)- 200
fuel filter- 45
in-tank sump to attach fuel line (replaces in tank fuel pump)- 75
air cleaner- 30
throtle cable(from junk yard) -20

Aproximate cost of swap- $1500

iv got a pretty much everything u need except carb intake fuel lines and throttle cable if u wanna work out a deal with ur harness and computer

A word of warning on EFI to carb swaps: don’t expect to pass emissions in any state that does comprehensive smog inspections, because it won’t happen.

Doing the swap: You must know how to read electrical diagrams and wire circuits properly to do the swap. Don’t take shortcuts or cut corners in the fabrication of the electrical or mechanical assemblies. If you do NASCAR quality work, the car will look good, run good and be as reliable as a carb’d car can be. Take pride in a job done with excellence.

Now that the rant is over, here’s some practical advice…

Do not use an EFI in tank fuel pump with a carb. You will never get the pressure/flow regulated properly. Either go full EFI or use a tank/fuel pump/fuel lines out of an 84 or earlier Stang. Fabricating your own setup is possible but there are some snags to overcome.

Do not attempt to leave the EFI in place in an attempt to control either the electric fuel pump or ignition. Doing so qualifies you for the “Road Kill Mechanics Award”.

If you try to use your current tank, you will need to pull the fuel pump out and fabricate a pickup tube & strainer sock to replace the fuel pump. Or you can have a sump fabricated and welded onto you existing tank. Many welding shops will not weld fuel tanks because of the dangers involved if the tank isn't purged properly.

You will need an external electric fuel pump unless you change the timing cover for one with the mechanical fuel pump mount on it. Rip all the EFI wiring out, and the computer controlled fuel pump won't work. You will need to add a relay & switch and wire in the existing inertia switch for an external low pressure electric fuel pump.

You will need to run some new fuel feed lines or braided hose. The 3/8" aluminum tubing works well, but you will need a flaring tool and bending springs to fabricate the lines. Braided hose is easy to run and route, but is much more expensive. It is about $3.50-$4.00 a foot plus the end fittings, which are $3-$4 each. Fabricating hose assembles can be difficult, but anyplace that makes hydraulic hoses can do it for you for an extra charge. See http://www.amazonhose.com for more information.

While you are at the electrical part, you'll need a Durspark or similar ignition system. The 85 Mustang GT 5 speed has a suitable Duraspark distributor with a steel gear compatible with the roller camshaft. 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.

go check out www.carbdford.com and http://www.jason.fletcher.net/tech/efi-carb/efi-carb.htm

fastangboi said:

nice copy and paste, i already read that stuff. thanx though.

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Youll want to listen to him man.. he is the best as far as electrical knowledge and troubleshooting assistance. you will be hard pressed to find anyone better.

As far as the tank / sending unit issue, i decided not to go with fabricating the stock sending unit. I bought one made specifically for the swap through summit.. mallory makes it. it makes it easy, with no worries about leakage. http://store.summitracing.com/partd...4294925239+400249+4294812406+115&autoview=sku

For the ignition, if youre budget minded, the duraspark is the way to go. i waited a little longer and went with the MSD distributor and 6AL box. I opted for the crane, but got a good deal on the dizzy that i couldnt pass up. Plus with all the accessories that msd makes, it will work out easier for me when i make upgrades or put the spray on it.

You can also find a TON of good info over at www.sbftech.com they know thier stuff over there.

fastangboi said:

nice copy and paste, i already read that stuff. thanx though.
.
CARLP-i was planning on running steel tubing, like huge brake line style. Steel braided would be a little over the top. And i was planning on doing a little more talking to 5.0 guys to see if they had some nice parts collecting dust.
.
DROPTOPFPM-id rather do a person to person trade. there are a ton of guys here in central FL with 5.0s. And i havent even turned a wrench to get this project going, im still in the research aspect. thanx though
.
Also what do i need to keep for my stock guage cluster to work? Speed is cable driven, I have a tach, but what will i have to do to keep my fuel level and oil pressure? i also have a coolant temp guage, and i could reall give a crap about battery voltage so im not worried about those.

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If you are one of those few people who do excellent work, please disregard my negative comments. They are not intended for you.

Quality, quality, quality…
Some of the motivation of my negative comments about carb to EFI has to do with the quality of electrical workmanship. A lot of the wiring “repairs” that I have seen on the road and in the junkyard looks like road kill. The other part of my negative view stems from people who can’t grasp the operation and tuning of EFI. Carbs have their own set of requirements and some learning is required to get the best performance. Every car is different and each installation needs to be tuned to get the best performance. Putting an “out of the box carb” or one from someone else’s car isn’t the way to success. There is no auto compensation for small variations in carbs like there is for EFI. Just throwing a carb on a car because you won’t bother to learn how EFI works is a poor excuse.

Your questions are the exact reason I said you need some good electrical skills to read and interpret electrical diagrams. To do the carb to EFI swap right, you need to either split the main EFI chassis harness open and remove the unneeded wiring or adapt an ‘85 carb’d V8 harness to fit your car.

Tools needed:
100-150 watt soldering gun (recommend WELLER 8200PK soldering gun kit 100/140W) $30 at Lowes or $40 at Home Depot
3/32”-1/8” rosin core electrical solder, 1/4 lb roll $6 at Ace Hardware, Home Depot or Lowes
Assorted sizes of heat shrink tubing. Buy long pieces and cut length to fit. It is cheaper that way. http://www.partsexpress.com/webpage.cfm?&WebPage_ID=346&CFID=169547&CFTOKEN=34300345
Hot air gun to shrink the tubing ($30-$40) Home Depot
Jeweler’s screwdriver kit $5 at Ace Hardware
Assorted automotive wire, 18-16 gauge 10’-20’ foot spools in different colors. $5 a roll at Advance Auto Parts.
Crimp tool for connector pins $9-$30 AutoZone, NAPA, Advance Auto Parts or other store
Ford connector pins AutoZone, NAPA or other store $5-$10 for a kit of 10-12 assorted pins

You will have $110-$150 in materials and tools if you don't already have them.

The water temp and oil pressure signals feed from the sender to the main harness through the 10 pin EFI engine harness. To utilize these senders, you need to identify the wires and find a way to reconnect them to the main harness after the EFI engine harness is removed. You need a weatherproof quick connector to join the sender wiring to the main harness.

You will need to construct a wiring harness from the ‘85 carb distributor to the Duraspark box if you go Duraspark, or other distributor to coil wiring.
The voltmeter picks up its signal from the switched voltage present on the instrument panel, so you don’t need to worry about that.

The fuel tank gauge is also independent of the computer wiring.

AutoZone wiring diagrams

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model Mustangs

How to solder like a pro - http://fordfuelinjection.com/?p=7 a must read for any automotive wiring job.

Soldering pigtails onto existing pins is road kill quality work as far as I am concerned. Take some time to study the way the Ford connectors are assembled and you will find that a small jeweler’s screwdriver will release the pins from the connector shell. New pins and a crimping tool are available from the Standard Motor Parts or Bendix Electrical parts line that the NAPA & Bumper to Bumper Auto Parts stores carry. Ask any auto parts store about Standard Motor Products or Bendix Electrical wiring parts. Those that carry them will be able to get the parts you need.

One of the interesting things about the Ford OEM wiring diagrams is that the connector shape on the drawing matches the connector shape in the car. That makes it easier to identify connectors and circuits. OEM Ford diagrams are available at for an 85 Mustang at http://www.helminc.com/helm/Result....edia=&mscsid=2M838NG3R5SR2MCS00A3HVE05T03C501 or can be found in the Chilton series of auto repair manuals for Mustangs.

The following is an excellent idea from a fellow Stangnetter who tackled the wiring plan the right way. He obtained the wiring diagrams from an 85 carb'd V8 Mustang and laid them out side by side with the diagrams from his car. He then traced out each circuit and the wire colors and connectors associated with them. After tracing the circuit and connectors for a circuit, he laid out the changes he needed to make. One circuit at a time made a difficult big job into many smaller easy to manage jobs.

Send me your email address and I will send you a zip file with the 89 Mustang wiring diagrams.

carlp said:

I just replied to another post about the same thing here are the parts I thought of plus a couple I forgot the 1st time (all of this stuff is middle of the road stuff, you can spend a lot more money if you try):
carb manifold -160
carb- 380
distributor- 200
MSD 6al- 220
carb fuel pump- 120
carb fuel pressure regulator- 50
fuel lines and fittings(braided)- 200
fuel filter- 45
in-tank sump to attach fuel line (replaces in tank fuel pump)- 75
air cleaner- 30
throtle cable(from junk yard) -20

Aproximate cost of swap- $1500

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Great breakdown...but after having done this swap...go ahead and double that approximate cost!

fastangboi said:

i cant solder to save my life. it always ends up clumpy and brittle

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Then this project isn't possible unless you get better or get a smart helper who can solder.

The How to solder like a pro - http://fordfuelinjection.com/?p=7 a must read for any automotive wiring job. Follow these instuctions and you can do a profeesional job.

you gotta swap ignition systems because the one you have now only works with the EFI computer, not stand alone

fastangboi said:

Also why do i have to swap over ignition systems. I figured mine thats on my 89gt is more advanced than a duraspark set-up

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From my first reply to this thead:

jrichker said:

While you are at the electrical part, you'll need a Durspark or similar ignition system. The 85 Mustang GT 5 speed has a suitable Duraspark distributor with a steel gear compatible with the roller camshaft. 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?s...&lvl=4&prt=127 for more information.

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