Black smoke...

You said the magic word that defines what your problem is... "carb"

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!



As far as a HP estimate, a 302-308 cubic inch Ford V8 without pressurized induction or NO2 will probably make 270-315 Rear Wheel HP. The driveline typically extracts a 15%-20% power loss due to friction and heat. The 440 HP number is in your imagination, and isn't realistic since you would need to make over 500 flywheel HP. The engine would need to make 1.65 HP per cubic inch, which will not happen without pressurized induction or NO2.

racing302 said:

Lol! I typed 440HP...i meant 400HP, but of course, not at the rear wheels!!

So the carb is my problem...ok...what to do?

Click to expand...

Two choices:
1.) Best answer: Convert back to EFI.

2.) Go find someone who really knows how to fix and tune whatever model carb you have. I'm not talking about some mechanic that throws a rebuild kit at it and calls it an "overhaul". Nor am I talking about borrowing a carb off your buddy's car or a carb out of a box from some auto parts specialty store. The carb will need to be setup for your car and tuned to the environment you live in. A carb tuned for Denver won't run worth beans in Miami Beach.

The black some is a sign of too rich a fuel mixture. That could be due to excessive fuel pressure, float level set incorrectly, leaking gaskets within the carb, bad power valve or incorrect jetting. That's why it is necessary to find someone who really knows his stuff to fix and tune the make and model carb you have.

Want to fix yourself or don't have deep pockets to pay someone to do it for you? Prepare to spend a lot of time Googling the make and model carb you have until you have found everything there is to know about it. Then and only then, attempt to take it apart and fix it.

Check the fuel pressure as a simple first step. It does not involve taking the carb apart. You'll need a low pressure gauge to tap into the fuel line near the fuel inlet on the carb. The pressure should be 4-6 PSI at idle and above.


Here's some EFI to carb conversion tips.
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. Some states will not title or issue license plates to cars that have been converted from EFI to carb. Be aware that you are violating several Federal laws concerning the removal of pollution control equipment. If you operate the vehicle on public highways and get caught by state or federal law enforcement (doubtful, but possible) you could be subject to fines and imprisonment. You won't get any more power from a carb than you will from EFI.

The following information is intended for informational purposes only. Operation of a motor vehicle modified in such as manner as described below should be limited to off road use only.

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.

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.


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. If the add on pressure regulator fails, you will flood the engine with gas and wash all the oil off the cylinder walls. That will cost you big time $$$. 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 computer 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. Do not try to wire the fuel pump without the relay. The 15-20 amps the pump pulls will overload the circuit. This will take power away from other items on the same circuit or cause the fuse or fuse link to blow.



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 Amazon Hose - Rubber, Hydraulic and Industrial Hose - since 1919 for more information.

For some help fabricating your own stainless steel hose assemblies, see
www.TurbineFun.com

For stainless steel braided hose and fittings for automotive use:

See Search Results for stainless steel hose - SummitRacing.com
Search Results for stainless steel hose - SummitRacing.com

stainless steel hose - JEGS High Performance

See http://www.aeroquip.com/pages/performance.html for more information on High performance automotive hose products

AN fittings require a 37 degree flaring tool. A standard automotive or household plumbing tool is 45 degrees and cannot be used with AN flare fittings. If you do, the flare is subjected to too much stress when the fitting is tightened, and is likely to fail or leak.

See MSC Industrial Supply Co. , McMaster-Carr or for the flaring tool you will need . Prices start at $85 and go up

MSC Industrial Supply Co.


McMaster-Carr


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 Crane Cams | Automotive Home Page for more information. Cost is about $400, which makes the 85 Mustang reman units look really appealing.

Tools needed:
Crimp tool for connector pins $9-$30 AutoZone, NAPA, Advance Auto Parts or other store
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. Parts-Express.com - Heat Shrink Index: 2:1 Ratio, 3:1 Ratio, Heat Shrink Kits
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.
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 can be found if you are willing to dig through the self help repair section of their website. Repair Info | AutoZone.com

How to solder like a pro - Ford Fuel Injection » How To Solder Like a Pro 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. AutoZone has a cheap kit with 10 pins for about $5. Just enough pins to leave you short when assembling a connector.

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 Helm Incorporated: Search Results 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.

racing302 said:

Wow!!

Thanks for the lenghty answer! But i do not want to switch back to EFI...

Someone told me 2day that my carb may need some cleaning, i.e., to go to my local speed shop and buy a spray can with carb cleaner and give it a thorough cleaning, and to let it dry for 24 hrs...

Would that make sense?

I really appreciate the time you took sir!

Click to expand...

It would be just as effective as cleaning your windshield...

I highly suggest that you lean what a carb is and how it works before you do anything else. Google is your friend and lots of good information is available for free if you are willing to take the time to look and learn. If you aren't willing, then get out your wallet, because it's going to get expensive. Uneducated mechanic = slow car and lots of money spent on things that didn't work.

Read the EFI to carb conversion checklist over carefully to see if your conversion is a quality job or roadkill done by someone too stupid or too lazy to figure EFI out and fix it. Quality work will closely resemble the description posted in the EFI to carb conversion checklist.

Your current problem is a rich mixture. Check the fuel pressure first. Most of the poorly done carb conversions use the stock EFI electric fuel pump. They drop the 40+ PSI down to the 4-6 PSI needed for the carb with a shunt return regulator. That is not the proper way to do it. If the shunt regulator fails, it will flood the engine and wash all the oil from the cylinder walls causing the pistons and rings to score the cylinder walls.

The proper way to do it is with a pickup that replaces the EFI pump and a electric fuel pump designed for carbs. You will have the 4-6 PSI you need to make the carb work correctly and will not flood if it fails.

Also note that the computer is not to be left in place to try and control the fuel pump or ignition system. That's a sign of more roadkill quality work. The proper way to wire the fuel pump is in a diagram in the EFI to carb conversion checklist I posted.