I recently bought an 85 F150, 300, 6 cyl, and am having problems getting it started. I has the feedback carb, but was converted to a duraspark dist. some time ago.

It ran when I bought it, but the wiring was a real rat's nest. It has a plow on it and was trying to get the plow lights to work. A lot of the wiring under the dash was hacked up and held together with wirenuts. As I was trying to trace them out a bunch fell apart. I thought I reconnected them right, but the truck will not start.

I want to rewire this truck from scratch starting with the ignition. This is pretty much what the wiring looks like
[IMG][/IMG]

I've spent hours on this forum reading up on duraspark and feedback carbs, but still have a couple questions.

At this time the truck will fire, but dies after the starter is disengaged.
I am using this diagram, but my pos. wire to the coil is green not red. It has this funky resister

[IMG][/IMG]

This is the coil with a pos. green wire and a yellow neg. wire
[IMG][/IMG]

Module
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So can I just wire this up like the diagram? Should I move the resister to the to the red wire and put the green wire on the neg side?

Or should I just get a new one from Napa?

Also the vacuum advance had fallen off the carb - is this te correct port?
[IMG][/IMG]

This truck is missing the air pump and a lot of the emmisions stuff is missing or disconnected.

I ordered a rebuilt1983 carb from Rock Island but it hasn't arrived yet. I just want to getting it working so I can plow my road this winter, I may not even register it.

Any thoughts or suggestions about my dilemma?

Any help would be appreciated

 

Are you getting power to the coil in the Run position?

 

Yes, 12 volts at the coil, thru the green wire, also getting a strong spark, plenty of fuel pressure.

I put a test light on the neg. side of the coil and it blinks when turning over. I did'nt touch the distributer so the timing should still be OK

Also have 12 volts at the red & wire at the module

Thanks, Mark

 

Welcome to FTE.

You need that resistor to drop the voltage to the coil to around 7V with the key in RUN; 12V is used only in START.

There are some pretty good guys out here who know this better than me so I'll let them answer more.

But I edited your title to hopefully be a bit more descriptive so as to attract them....

 

The resistor looking deal inline in the green wire looks like a diode. It looks like someone hacked that piece of wire out of the A/C system. You may need to start from scratch, as this thing in severely hacked. You may be chasing your tail trying to see whats going on with the existing wiring, not to mention it's a fire waiting to happen.

I've converted 3 of these trucks so far to work with Duraspark, and a '70 F100 that used to have points, so I'm super familiar with it.

All that the truck needs to run is a 12v hot in START AND RUN signal to the red wire on the DSII box. The white wire aids in cranking when cold (changes timing) and usually hooks up to a hot in START ONLY wire...although not neccessary out here in AZ, it may benefit you in the winter. Make sure the positive side of the coil gets a hot in START AND RUN signal too. The negative side of the coil needs to be hooked up to the green wire coming out of the box. Make sure your orange, purple and black wires coming out of the box are hooked up to the distributor correctly as well.

Let us know what you come up with!

 

That IS a rats nest.
If it were me I would just get a Duraspark coil and the engine harness with the horseshoe connector at the junkyard.


Your diagram is WRONG, wrong, wrong.
Junkyardidiot.com....

Your "green" coil wire should have 7+/-V in 'run' at the coil coming through the resistor.
12V Power to the red lead of the DSII module at ALL times in 'run'
12V Power to the white while cranking, At least they (kinda) got that right.
That is the one that should be connected to "I"

But that "I" terminal wasn't ever used in '80's trucks.
It is only powered while cranking, THAT'S why it dies when you let off the key.
The DSII box is not getting the correct voltage.
You'd need to tap the module into the red wire BEFORE the resistor.

Much better if you pull power from the proper ignition switch wires.
I posted a simpler color coded wiring diagram in a thread last week.



Try reading this too; Duraspark II conversion

 

Actually the white wire tells the DSII module to retard the timing while cranking.
Lessening the load on the starter and making HOT starts easier.

 

Thank you! I think this information is just what I was looking for. "a rats nest" is putting it politely. I will rewire this whole truck as time permits. Right now I just want to get it running again. If I can just get it to run, the snowplow lights, heater and wipers to work before winter I'll be very happy.

When you say Duraspark coil - do you mean the old style round one?

I printed your diagram out and will see if I can make some progress today - **will throw the junkyard guys away**. It might be a few days before I can check w/ a junkyard, but I will keep you informed of my progress.

 

Yes the round one.
With the Duraspark II system there was a slip on connector that is 'C' shaped. (we call it the horseshoe.)
That coil has a very hot spark, that is why you need the larger distributor cap and adapter.

I don't have an I6 so mine is located on top of the engine.
Let me see if I can search up a picture for your truck.

 

ArdWrknTrk is absolutely right. As it stands, your truck is a fire hazard the way it has been thrown together. The best thing you could do for your truck is to take all of that mess off and completely start over. If you get all the *correct* Duraspark components and wire it up the way it is supposed to be, you will have a very reliable ignition system that starts quicker than any other vehicle you own.

Here are two great links to help you:

https://www.ford-trucks.com/forums/9...wontt-run.html

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

 

Thank you Lariat!
It was dyingtolive's thread I was thinking of but didn't find it right away.

 

Everyone on this forum has been so helpful, I wanted to post a follow up since I started this thread

I think I was having several intermittent problems, which made this a real pain in the *** to get running.

As suggested I replaced the square coil with an old style round one. I picked up a mallory coil bracket that I bolted to the stock bracket w/ bolts and large washers. I don't think it was worth the 8 bucks but it made for a clean looking install.

I suspected that the issue had to do with the white wire going the module, because it would fire but then die. I replaced the"AC diode" with a resister wire from carquest ($18 bucks!) After chasing & testing wires trying to find the "start wire" from the ign switch I suspected there was a problem with the ign switch. Out of frustration I threw in the towel and switched the module over to the GM 4 pin by following the instructions here. Dirt cheap Ignition I had one laying around from a chevy small block. (By doing this I illuminated the need for the white wire)

It started and ran, I got in and started to take it for a test drive, got about 100 yards and it died. - wouldn't fire at all. went back later and it started and ran for a few minutes.

Read some more stuff on this forum and Chiltons and saw this was a symptom of a bad pickup coil. When it gets hot it quits working. Got out the ohm meter and tested the distributor as outlined in the Chiltons and sure enough it was no good.

Went to buy a new pickup at Autozone, it was $28.00, A rebuilt Carbone Distributor Part Number: 30-2669 (lifetime warranty) was only $19.00 more. My old Distributor was pretty worn out looking so I just sprang for the whole unit.

Being VERY careful to mark exactly where the rotor and body was on the old one I replaced it with new one and got the gears lined first try. It fired and kept running. I was sort of in a daze that it's actually fixed- I spent at least 20 hours repairing and testing the wiring in the previous owners rats nest since my last post.

It did run very rough - I had read that using the GM ign. module changes the timing 3-4 degrees, plus replacing the dist. didn't help. I havn't needed a timing light in years, so of course I couldn't find mine. so I timed it by ear. It doesn't help that I still have the feedback carb and the emmisions is butchered.

I'll work on that as soon as my old style carb arrives any day now from Rock Island Autoparts. I'm sure I'll have questions/help with that.

I still need to address the ign. switch problem - you probably don't want to know how I got past that

The morel of the story is to test the dist. pickup when having duraspark system problems. It don't cost nothing and is easy to do. I can post the info from Chiltons if anybody need it.

Thanks again for every ones help

 

I like reading stories like that, thanks for posting.

 

Please do post it.
I know what resistance I found in my old pickup and the new one I installed in my distributor.

Not long ago there was a thread showing a test procedure for the DuraSpark distributor.
Let me see if I can find it and post a link.

 

Here ya go: I knew my pickup was bad because I had 0 resistance between the orange & purple wires instead of the required 400-800

I actually copied this from Autozone's website, but they copied it from Chiltons



To test the stator (also known as the magnetic pickup assembly), you will need an ohmmeter. Run the engine until it reaches operating temperature, then turn the ignition switch to the off position. Disconnect the wire harness from the distributor. Connect the ohmmeter between the orange and purple wires. Resistance should be 400-800-. Next, connect the ohmmeter between the black wire and a good ground on the engine. Operate the vacuum advance either by hand or with an external vacuum source. Resistance should be 0-. Finally, connect the ohmmeter between the orange wire and ground, and then purple wire and ground. Resistance should be over 70,000- in both cases. If any of your ohmmeter readings differ from the above specifications, then the stator is defective and must be replaced as a unit.

If the stator is good, then either the electronic module or the wiring connections must be checked next. Because of its complicated electronic nature, the module itself cannot be checked, except by substitution. If you have access to a module which you know to be good, then perform a substitution test at this time. If this cures the problem, then the original module is faulty and must be replaced. If it does not cure the problem or if you cannot locate a known good module, then disconnect the two wiring harnesses from the module, and, using a voltmeter, check the following circuits.

Make no tests at the module side of the connectors.

Starting circuit: Connect the voltmeter leads to ground and to the corresponding female socket of the white male lead from the module (you will need a jumper wire with a blade end). Crank the engine over. The voltage should be between 8 and 12 volts.
Running circuit: Turn the ignition switch to the ON position. Connect the voltmeter leads to ground and the corresponding female socket of the red male lead from the module. Voltage should be battery voltage plus or minus 0.1 volts.
Coil circuit: Leave the ignition switch ON . Connect the voltmeter leads to ground and to the corresponding female socket of the green male lead from the module. Voltage should be battery voltage plus or minus 0.1 volts.

If any of the preceding readings are incorrect, inspect and repair any loose, broken, frayed or dirty connections. If this doesn't solve the problem, perform a battery source test.

Battery Source Test
To make this test, do not disconnect the coil.

Connect the voltmeter leads to the BAT terminal at the coil and a good ground. Connect a jumper wire from the DEC terminal at the coil to a good ground. Make sure all lights and accessories are off. Turn the ignition to the ON position. Check the voltage. If the voltage is below 4.9 volts (11 volts for Dura Spark I), then check the primary wiring for broken strands, cracked or frayed wires, or loose or dirty terminals. Repair or replace any defects. If, however, the voltage is above 7.9 volts (14 volts for Dura Spark I), then you have a problem in the resistance wiring and it must be replaced.

It should be noted here that if you do have a problem in your electronic ignition system, most of the time it will be a case of loose, dirty or frayed wires. The electronic module, being completely solid state, is not ordinarily subject to failure. It is possible for the unit to fail, of course, but as a general rule, the source of an ignition system probably will be somewhere else in the circuit.

IGNITION COIL TEST


The ignition coil must be diagnosed separately from the rest of the ignition system.

Primary resistance is measured between the two primary (low voltage) coil terminals, with the coil connector disconnected and the ignition switch off. Primary resistance should be 0.3-1.0-.
On Dura Spark ignitions, the secondary resistance is measured between the BATT and high voltage (secondary) terminals of the ignition coil with the ignition off, and the wiring from the coil disconnected. Secondary resistance must be 8,000-11,500-.
If resistance tests are okay, but the coil is still suspected, test the coil on a coil tester by following the test equipment manufacturer's instructions for a standard coil. If the reading differs from the original test, check for a defective harness.