Hey all,
My brother's having some issues with the 1986 carb'd 351 in his Bronco. Sometimes it just won't fire up, and will crank and crank without any results until the moment he'd stop trying to start it.

He said he pulled the wire off of the coil and watched the end while someone else tried to start it and there wasn't any spark until they let off the key, and then it would spark once.

Any ideas what may be causing this? Ignition module? Coil? Starter solenoid? Etc.
Thanks.

 

Yup, IF you have the DuraSpark II ignition system!

When you turn OFF the DuraSpark II ignition system, it fires one time. It really helps in troubleshooting.

Disconnect the plug to the distributor, and ohm out the pickup coil that is inside via the wires.

I went out to the garage and dug up an old intermittent one that caused me problems on a Ford wagon years ago. It has Purple, Orange, and Black wires on it. The Black is a ground, the pickup's coil is the Purple and Orange wires, at least on this one.

If it measures open, that's the problem. Pretty easy to fix with the distributor in place. Remove roll pin holding in the reluctor (the toothed wheel) carefully, pull off the reluctor, then remove snap ring that holds the pickup coil/magnet assembly down. at least that is what I remember from about 15 years ago!

 

Thanks for the response.

Are you talking about the distributor or the ignition control module in your description above?

So, if it measures open, what does that mean?

Open up the distributor, remove reluctor, etc (BTDT), and then what?

I wasn't sure if I missed something.

 

The pickup coil is inside the distributor. It's wires extend out of the distributor to a plug. Unplug it, and check the resistance into the distributor side. You are trying to determine whether the pickup coil still has continuity (good), or is open (deceased).

If it is open, I gave steps how to remove the old one. And as they say, reassembly is the reverse of disassembly.

Here is a link to a pic of the pickup coil. It is an assembly consisting of a pickup coil and a magnet. It replaces as one part.

More Information for STANDARD MOTOR PRODUCTS LX204

From a 1982 Ford manual, the pickup coil should have resistance in the range of 400 - 1300 ohms if it is good. I can't measure my old one, 'cuz it's open. Anywhere in or near that range is good.

 

Awesome. Thanks Torky2, I'll get with him and we'll look into it.

I figured that's what you meant after reading a few other posts that people were saying about the Duraspark but wanted to be sure.

 

Well, took the ICM down, it failed 4/5 tests. It was only a couple years old.

 

[/B]the van i have does not have reluctor in the distribator

 

I have a 1982 ford econoline van it only firers when let off the key and it does not have reluctor in the distributor it has a the coil is separate from the distributor

 

Rebuild the distributor, that should get you going.

 

When "letting off key" you "only get fire to coil"
everyone has good points as to fix this problem and I commend them!
there however is another way that might have made
"this happen"
bought an ignition control module for my 83

still had the no power at start problem,then realized it!
the red-run wire. And the white -start wire were backwards!FROM THE FACTORY. a motocraft one at that...sos what do I do?
I spliced and put the colors back.
new problem..
won't start at all.
(old owner tried fixing this problem before)
long story short fellas..and gals.

don't switch the acc/run wire and the START wire. Only half of the system works then.
you see when you put your switch to START ,accessories are CUT OFF.
put lower column BLADE SWITCH CONNECTOR WIRES BACK TO FACTORY. And make sure your NEW module's wire colors match at the plug -ins.

thank y'all, have a nice day!

 

Yes, I know I'm responding to a 15-16 year old post (by Torky 2). But I wanted to thank the him for his help. I tried to find a way to direct message but looks like last activity was 2022. Through his response to the OOP (Original, Original Poster), he at least pointed me to the pickup. I indeed found no continuity. It turned out it wasn't the pickup being dead, it turned out the wire was broken. I can only assume I pinched it when messing with the ill fitting cap. I suppose it was hanging on by one single thread and decided to finally give up randomly as it was running one moment and then wouldn't start 5 minutes later. I wasted a lot of time 'chasing'.... That 'one spark on off' was throwing me before I saw the explanation of how Duraspark works.

Just a general thank you to the knowledgeable people that take their time to post small bits of information that can help someone this many years later and the forum/administrators in general for given your time. This forum has become my 'go to' on actual help to solve problems and questions. Thank you.

 

Glad it was helpful!
That's what's so great about these forums. The information sticks around, and so many people can read it and be helped by it without ever even knowing they came by.

 

Here is the Ford tester for the breakerless system
A basic test for the Stator (Motorcraft DU5) is to see if the negative side of the coil blinks as you crank the motor over trying to start it
Ford calls the pickup coil in the distributor a stator
* These testers are the key

 

The one spark or trying to run as you turn the key off is a classic sign of module failure
Same thing happens when the roll pin in the distributor gear shears
So, verify the rotor is turning first