I have an 86 f150 300 4.9l. I bought this truck cheap so I expected trouble. First the carb kept flooding out. I rebuilt it but that made no difference. I towed to the shop they told me I needed a new carb. They suggested I get one off of an earlier year and do away with all the electronics and crap. I replaced it with one with no electronics on it. Now it will run and idol for a few minutes then will die. I have replace the fuel pump. Under any load the engine will stall. It is also hard to start cold and after it stalls. I am at the end of my rope. My wife is about to kill me if I don't get it running. PLEASE HELP Thanks.

 

First the bad news; your truck NEEDS an electronic carb for the distributer to work right.
Now the good news; it's pretty straightforward to swap to the Duraspark ignition. You'll need the dizzy, an ignition module with a blue grommet, a regular ignition coil, and the wiring harness from the left inner fender to the dizzy. It's all plug and play: the only exception is if you lack the ballast resistor wire, andf it's easy to add. To find out, you'll want to unwrap the wire loom (with the round-ish plug) leading to the cowl and see if it has a big pink wire- if it does, you're golden.
Lariat 85 might chime in and help; he was a big help to me.

Frank

 

I understand where the shop was coming from when they told you get a carburetor from an earlier year and "do away with all the electronics and crap." The problem is, it is not that simple.

Your truck originally used the EEC-IV computer to control most of the engine functions. The EEC-IV relies on inputs from various sensors placed around your truck related to emissions, ignition, and, you guessed it, the carburetor your truck originally came with. The carburetor your truck came with is known as a "feedback" carburetor. The computer reads the signals from all the inputs, and then actually adjusts the air/fuel mixture on the carburetor for maximum efficiency and performance.

On these computerized "feedback" systems, you cannot just start taking off components and changing things as if it were not. Because of the EEC-IV computer, everything must work together. For example, by replacing your feedback carburetor with one that is not, the EEC-IV computer now has no idea what to do with a carburetor that it can't adjust, so the system reverts to a fail-safe "limp home" mode. This results in your timing, which is also controlled by the computer, will lock itself in one position. The vehicle should still run, but performance and economy will suffer greatly.

What you need to do to get your truck running properly is to either put the original carburetor back on, or you can keep your current carburetor and go all out and remove the EEC-IV computer and replace your entire ignition system with a "stand alone" ignition. This can get expensive. By going with the latter option, most of your emissions components will be rendered useless, something to keep in mind if you have emissions testing in your area.

 

What do I need to put a stand alone system in. Can I junkyard the components? Thanks to both of you most info I have gotten.

 

YES, you can "junkyard" the components. But first, answer this question:

Does your state require emissions testing? If yes, your truck will not pass VISUAL inspection if you do this!

If you do not have inspections, read on. Did you get your non-electronic carburetor from the junkyard? If so, you may find these components on that truck. If not, ask for the following items for a 1980 - 1983 Ford F150. You may buy new or used:

- distributor (vacuum advance)
- ignition module (blue grommet)
- ignition coil (canister style)
- spark plug wires
- You will not need to buy a ballast resistor.

I. Ignition wire harness:

a.) 1980 - 1983: 255, 300, 302, 351, 400, 460 used Duraspark II ignition (except for some California vehicles)
b.) 1984 - 1986: 300, 302, 351 used TFI-IV ignition, EEC-IV engine computer, and feedback carburetor or electronic fuel injection
c.) 1984 - 1986: 351 H.O., 460 used Duraspark II ignition

From 1980 - 1983, almost all F150s used a conventional carburetor and the stand-alone "Duraspark" ignition system. From 1984 - 1986, almost all of these vehicles used an engine computer, "feedback" carburetor, and switched to the TFI-IV ignition. So Ford used the same plug-in connectors for each system. In this way, if your truck happened to have the 351 H.O. or 460 from 1984 - 1986 for example (these did not use an engine computer) Ford just plugged in the Duraspark II harness. If you had a 300, 302, or 351 engine from 1984 - 1986, Ford plugged in the TFI/EEC-IV wire harness that ran off the engine computer.

II. Duraspark II harness differences:

a.) If the truck has a V8 and a factory tachometer, there will be an extra plug connection for it included in the wire harness. This extra plug will be grouped with the ignition module plugs. On this plug, there will be both a green and a black wire. The green wire is to power the tach and the black wire is a ground that is needed in order for the tach to read correctly on all V8 applications.

*If there is no tach, the plug will not be in the harness and you will have to wire it in another way yourself if you want your factory tach to work.*

**If you use this harness on an I6 engine, you will have to cut or remove the ground wire or the tachometer will read too low.**

b.) If the truck has an I6 and a factory tachometer, there will be an extra plug connection for it included in the wire harness. This extra plug will be grouped with the ignition module plugs. There will be a single green wire. This green wire is to power the tach.

*If there is no tach, the plug will not be in the harness and you will have to wire it in another way yourself if you want your factory tach to work.*

**If you use this harness on a V8 engine, you will have to find a way to ground the tachometer, or else it will read too high.**

III. At the junkyard:

Go to a junkyard, and look for an (Duraspark) ignition wire harness from an F-Series truck. (see I. Ignition wire harness) If possible, try to find a harness that matches your application. For example, if your truck has a 300 engine and factory tachometer, try to find a donor truck that has a 300 engine and a factory tachometer. All V8 engines use the same harness. Although not necessary, this will be the easiest way to convert your vehicle without any other modifications. If you can't find your exact application, only a slight modification will be needed. (see II. Duraspark II harness differences) All you have to do is unplug the harness from the junkyard vehicle. It really is this easy.

IV. How to remove the harness from the donor/junkyard vehicle:

You need to unplug the harness from the distributor, and the two plugs from the ignition module. Next, take the horseshoe connector off of the coil. Then unplug the wires and connectors from the oil sending unit and temperature gauge sending units. Gently begin to pull the wire harness out (it will be all one piece) and you will find two more plugs that you will need to unplug toward the back of the truck (driver's side) that connects the wire harness to the vehicle. That should be it, all one piece and the exact size you need. I paid $25 for mine.

By using the factory harness,it is as simple as plugging it in! There will be NO wire cutting, splices, ballast resistors to wire in, or extra wires hanging around that you don't need. Very neat and factory correct as well. I have done this conversion on my own 1985 F150.

Other than the tach connections, all the harnesses should be the same. Once you get the harness, I will tell you where to connect it to your truck's existing harness and how to find the factory ballast resistor wire your truck already should have that is activated when plugged directly into the junkyard/donor Duraspark wire harness.

 

I am getting the impession you have forgotten more than I will ever know. Hopefully I will head to the junkyard tomorrow. I will keep you up to date on my progress or lack there of. Thanks a million.

 

Most excellent post, LARIAT 85! I tried to "rep" you, but was unable to... due to having done so in the recent past.

 

check summit racing. They have great summit brand hassle free pretty close to plug and play systems. It's not gonna be as cheap as junk yarding it but a heck of a lot easier and you get warranty, installation instructions, etc.. This would be my suggestion. Buy this follow lariat 85's great instructions where applicable and you will be in smooth sailing land. Lariat 85 is one of the best fountains of knowledge here. Respect.

Dimitri

 

"Fountain of knowledge?" That has a very nice ring to it!

I'll take that, and say "thanks!"

 

Lariat 85 you da man. I have an 86 4.9L inline 6 with the TFI-IV ignition(no tach). I would like some confirmation. The way I interpret your post I can swap to the DurasparkII with my existing wiring harness??
The ballast resistor(or resistive wire) is integral to my harness?

I appreciate your advice, saves me a lot of time, also can I remove the computer if I have replaced the carburetor an Ignition system to the earlier models, or does it perform other functions.

Thanks in advance.
BTW first post, new member.

 

Thanks, 86XLInline6, and welcome! I am glad you did a search first and found my post!

Yes and yes. The resistor wire is part of the wire harness on all 1980 - 1986 models, only it is bypassed and unused on vehicles that are computer controlled. It is activated when the Duraspark wire harness is plugged in.

You will end up removing your distributor and the ignition module that is connected to it, the ignition coil, the" feedback" carburetor and all of its associated wiring, the MAP sensor on the passenger's side inner fender, the O2 sensor on the passenger's side exhaust manifold, the EGR under the carburetor and solenoids on the valve cover (these were electronic EGR valves), the EVAP solenoids that run from the carburetor to the charcoal canister, and finally the entire EEC engine computer and all of its associated wires that go through the firewall and into the cab. The computer was located under the dash on the left of the ash tray on my truck.

Also, your original coil wiring, oil sending unit wire and coolant temperature sending unit wire will be removed as well, as it is part of the EEC harness. The replacement Duraspark harness will have a "horseshoe" connector for the new coil and both of the sending unit wires you need.

Take note of where you remove the Duraspark harness from the donor vehicle, because you plug it into the same place on your truck. You just have to remove your existing wire harness and plug in the Duraspark harness in the same factory connectors found on your truck. Then you simply bolt on the new distributor, ignition coil, ignition module, and carburetor. It is simply a matter of using the connectors on the harness and hooking up the components.

After you get all of the electronic emissions equipment removed and your truck running again, you may get your EGR and your EVAP system functional again if you wish by going to an earlier all- mechanical setup that controlled these functions using valves and vacuum switches. These can be found on the pre-electronic models. It would be easiest to get all this from a junkyard vehicle, or the same vehicle you get the Duraspark harness from.

Yes, you may remove the entire computer. On my own 1985 302, there was a rubber plug on the firewall that had a gang of about sixty wires stuffed into it that led to the cab under the dash, where the computer was located. There is going to be a big hole left in that firewall plug when these wires are removed. I would suggest grabbing the rubber firewall plug from the same vehicle you get the Duraspark harness from, as it will not have a big hole in it to accept all of those computer wires. My advise would be to remove the EEC computer last. Make sure you have everything in the conversion hooked up correctly and running first, and then remove it.

Good luck!

 

I just found this post that has some good photos that will help you:

https://www.ford-trucks.com/forums/1...on-how-to.html

 

Great info. I have an '86 F150 4x4 300 with a factory tach. I'm getting ready to do the conversion. I've not had very good luck finding a harness. The only one I've found has $100 price tag on it. I will probally make my own.

I have Three plugs.
Plug #1 is a half round connector and has 3 wires from the cab side White with a blue stripe, White with a Pink stripe and a Red with a Blue stripe. The plug that hooks to it has 2 wires. White with blue stripe and red with Blue stripe.
Is this the plug that the module hooks to that connects to the ignition switch and the start terminal on the starter relay?

Plug #2 looks like a football with one square end. It has 2 wires on the cab side one Green with a Yellow stripe and one Black wire. Coming out on the other side is only the Green with Yellow stripe. Is this my tach?

Plug #3 is round with 4 wires in and 4 wires out. Red with White stripe both sides of the connector. White with Red stripe both sides. Red with Yellow stripe both sides. Red wire with Green stripe cab side. This wire is bigger than the other wires. On the other side of the connector is a Brown with White stripe. Are these for my guages? Is the bigger wire for the Amp guage?

I have a wiring diagram that shows a wire from the + side of the coil to the "I" post on the starter relay. Does this have to do with the ballast resistor and the big pink wire? Would this have something to do with extra wire in plug #1 The White with Pink stripe.


Can I unrap my existing harness and use the wires for the circuts that the connectors are hooked to? Like for the guages?

Thanks for the great write up.

 

#1 connects to the 2 wire power plug on the DS2 module. Your truck gets the “Starter Engaged” power input to the DS2 module from the key switch, not the starter solenoid. Your starter solenoid will not have the “I” post on it.
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#2 is your tach signal
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#3 has water temp, oil pressure and coil positive, which is the larger wire.
You also have a 4<SUP>th</SUP> wire which is hot with <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com</st1:City>KEY <st1:State w:st="on">ON</st1:State> that you will not use.
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On your last question you can reuse the current harness but you will have to cut out the extra 4<SUP>th</SUP> hot wire so the coil is only feed down stream of the ballast wire.
<O</O
If you can’t find a harness it is easer to just use a GM 4 pin module and your current coil until you find a good harness.
https://www.ford-trucks.com/forums/1003828-any-80-83-i6-part-trucks-left-anywhere.html#post9488179

Jim

 

Jim, I have a quick question about the distributor that I want to use. I am doing the conversion on my '86 F150 I6 to the non-FB carb and DSII coil and dist. system. I have the parts from a '81 F150 DSII module and wiring harness and the carb, coil, and distributor from a '76 F150 I6. Do you see any problems with me combining the two systems? The '76 distributor has points and condenser.