Another Duraspark issue

rjcruz27 · Jan 9, 2020

1974 bronco that came with a duraspark i module. My painless harness needed the duraspark ii. I got the new module and engine harness from painless. I have zero spark. Everything is getting right at 12v except for the coil. I’m at 11.9 and while cranking it drops to 9.90v. I am at a loss for what it could be. Some forums are saying switch out the rotor cap and this and that. I’m just looking for anything to point me to the right direction. Anything will help.

Hazegray · Jan 9, 2020

Did you remove the resistor wire (pink) from the equation? See if this helps https://www.ford-trucks.com/forums/1541605-duraspark-2-conversion-wiring-and-troublshooting.html

gr8scott · Jan 9, 2020

Is there a (brown?) wire running from the starter rely I post to coil positive? It bypasses the resistor wire when the key
is in crank position, sending 12V to the coil. Sometimes these DS ignition systems need the resistor. Mine did.

jckkys · Jan 9, 2020

Read this;https://pantera.infopop.cc/topic/duraspark-vs-msd-distributor. You will see that Duraspark I was introduced in 1977 and only in Cal. 1974s had Breakerless ignition with a different harness than Duraspark II. The painless harness is correct for Duraspark II so something else is wrong. There are trouble shooting guides for finding the problem. But you have the right parts.

EPB72 · Jan 9, 2020

Jckkys ,,you have that backwards duraspark II was for California and not all vehicles had it ,,they were the module with the red wire strand..it had higher spark output for leaner burning cal emissions.Duraspark I with the blue strand is your best option because good used modules are harder to find,and the only one you can still get in motorcraft is the blue strand made in mexico...And yes 74 had breakerless ignition and the wiring is a little different. Rjcruz27 put a test light on the neg side of coil and see if It pulses when you crank it over,,what module is in the truck now where the wires go in the module what color is the plastic strand?

SHX669 · Jan 9, 2020

It sounds like you installed a new Painless wire harness and their Dura Spark harness and went with DS II -- ?? Painless has great instructions - maybe read them again and see if you connected something wrong. You should have 12 volts or close to that while cranking.
Are you getting spark out of the coil but not out of the dist cap or no spark from the coil ? Have you checked the ground from the coil ? Are the ground wires for the tach and distrubutor tight and in good condition?

EPB72 · Jan 9, 2020

https://www.cj-8.com/forum/images/imported/2014/01/a2unujaz-1.jpg

gr8scott · Jan 9, 2020

EPB72 said:
Jckkys ,,you have that backwards duraspark II was for California and not all vehicles had it ,,they were the module with the red wire strand..it had higher spark output for leaner burning cal emissions.Duraspark I with the blue strand is your best option because good used modules are harder to find

Sorry EPB72, but you got it backwards. Duraspark I has the red strain relief and was used in Cali only. It had the higher spark output
for leaner burning cal emissions. duraspark II has the blue strain relief and was used in the other 49 states.

gr8scott · Jan 10, 2020

jckkys said:
Read this;https://pantera.infopop.cc/topic/duraspark-vs-msd-distributor. You will see that Duraspark I was introduced in 1977 and only in Cal. 1974s had Breakerless ignition with a different harness than Duraspark II. The painless harness is correct for Duraspark II so something else is wrong. There are trouble shooting guides for finding the problem. But you have the right parts.

Hey jckkys, after reading that article I'm almost tempted to give Duraspark I a try.

Sorry for the hijack OP. Have you verified the wiring per the instructions? I see you're a contributor, should post up some pictures.

Here's a nice chart from the article.

EPB72 · Jan 10, 2020

YEP my bad,,sorry Jckkys….. must of misread something a while back ,,,,,,https://www.crankshaftcoalition.com/wiki/Duraspark_ignition

ransil · Jan 10, 2020

do a resistance check at the distributor plug and the dura spark plugs.

are you using a blue grommet?

Past few years I have bough a bunch of bad pickup coils.

jckkys · Jan 10, 2020

The Cal only Duraspark I does put out more voltage but there are no original modules and I don't trust the after market. I also have no reason to believe the Duraspark II isn't making enough voltage, and all the parts were OE on '76-'77 EBs.

rjcruz27 · Jan 17, 2020

How do you do a resistance check?

The green “tach” wire I don’t have connected to anything because I’m not running a tach. How do you ground the coil?

I’m not getting 12v to the coil. I have 12v until I crank then it goes to 9.90v.

What’s the best way to find where I’m losing the power?

I switched out my ignition switch and module.

rjcruz27 · Jan 17, 2020

How do you do a resistance check?

The green “tach” wire I don’t have connected to anything because I’m not running a tach. How do you ground the coil?

I’m not getting 12v to the coil. I have 12v until I crank then it goes to 9.90v.

What’s the best way to find where I’m losing the power?

I switched out my ignition switch and module.

rjcruz27 · Jan 17, 2020

Yes I’m using blue grommet

jckkys · Jan 17, 2020

Your voltage readings are good. The coil secondary is grounded through the spark plug. The primary is grounded at the module.

gr8scott · Jan 31, 2020

jckkys said:
The Cal only Duraspark I does put out more voltage but there are no original modules and I don't trust the after market.

Found them! NOS Duraspark I modules...

https://www.hiltopautoparts.com/pro...incoln-mercury-california-models-red-grommet/

DirtDonk · Jan 31, 2020

Such a deal. Found a used, gooey and half melted one on e-Bay for $199!
You can even see the circuit board components through the almost clear potting material on the back, and what looks like rusty oooze coming out of it.

But hey, it's "NOS" too, right?
At this point I'd only use one of those if my Ford already had the Red one from the factory and I needed a replacement to keep it stock.
And even then, I would be very tempted to just go Blue, or go aftermarket and call it good.
As much as I appreciate a good Dura Spark, and like getting the best bang out of the ignition, after they go over $40 bucks or so, I start looking for simpler alternatives.

Paul

DirtDonk · Jan 31, 2020

Not that those aren't cool by the way. They are.
I bet they weight twice as much as the modern imported ones, and would likely last another half of a lifetime of the vehicle.

But the price just puts me off.

Paul

gr8scott · Feb 1, 2020

Hey Paul, I ran across that today and figured I'd post it up. I was intrigued by the description of the Red module in the link Jckkys posted. Here's an excerpt:

"The Duraspark I ignition produced the most consistent and most potent spark of any Ford ignition. This is Ford’s best ignition for igniting lean mixtures or rich mixtures, which was the purpose for its existence. The ignition will ignite mixtures the Duraspark II ignitions can’t. The dynamic dwell feature gives this module good high rpm performance too. This ignition’s design was more elaborate than the design of the Duraspark II ignition, and therefore it was more costly for Ford to manufacture (replacement Duraspark I modules cost several times the price of replacement Duraspark II modules)."

Another Duraspark issue

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