Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: blu84302 on December 03, 2007, 10:22:05 AM

Title: Killing Duraspark Boxes
Post by: blu84302 on December 03, 2007, 10:22:05 AM
Any Ideas why I might be doing this?  It's a 5.0 with duraspark. 

New TFI Coil, Dissy, Battery, Ignition Box.

I've done some testing with mixed results.  I did fry the first box.  This second one seems to be limping along.  It'll run then loose spark.  (Used timing light to tell when spark was lost)  However the module tested good at the parts store.  They even tested it 10 times to see if it was getting hot.

Constant 12 Volts to the ignition and coil. 

Hoping someone has had this problem before and can give me some direction.

Thanks.
Title: Killing Duraspark Boxes
Post by: Chuck W on December 03, 2007, 11:04:31 AM
"TFI" coil?  Are you using an e-coil?

I thought the DuraSpark units prefered the old canister-type coils?
Title: Killing Duraspark Boxes
Post by: blu84302 on December 03, 2007, 05:45:02 PM
It's actually interchangeable.  Ford and their infinite wisdom.
Title: Killing Duraspark Boxes
Post by: Chuck W on December 03, 2007, 05:55:17 PM
Hrmmm.  Well I'm not sure.  I've never had that issue.  The old black '83 5.0 we had I swapped in a DS ignition (PO had installed a point dist :rolleyes:) and we never had a problem with it.  It was a used DS box even.  I only used canister coils on it though.
Title: Killing Duraspark Boxes
Post by: softtouch on December 03, 2007, 08:46:48 PM
Here is how it should be wired up.

(http://users.rcn.com/jroyle/Dura%20II.jpg)
Title: Killing Duraspark Boxes
Post by: blu84302 on December 04, 2007, 12:38:05 AM
Yeah, it's close to that except I'm not running the white wire for the timing retard.

Also I'm not using the ballast bypass because it's not nessesary with the TFI coil. 

I did ground the case out today.  Before it wasn't grounded because it uses a gound in the dissy.  Hopefully that will keep it from heating up alot.
Title: Killing Duraspark Boxes
Post by: jcassity on December 04, 2007, 02:41:10 AM
Those dsII modules need to be bolted down.  They need that ground always and forever.  Many ppl remove the plug and slap in a new module and let it just lay in there "for test purposes" only before they actually bolt it down.  Time marches on and its broke again.

as for the balast,, what are your reasons why you think you dont need it?

I think you do


in additon to softouch's supplied layout, below are a couple more for you.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 04, 2007, 07:59:37 PM
I belive a TFI coil is a resistance coil.  However I'm starting to think it's not applicable with a DSII box. 

I fried the second box today.  I still have 2 more as backups.  I did buy a ballest and an oil filled coil today. 

Does it matter if I put the oil filled coil on the fender?  I've always seen them on the motor and I'm not sure if it's an issue.  If this module fries then I'm going to mount the ballast and oil coil.
Title: Killing Duraspark Boxes
Post by: TurboCoupe50 on December 04, 2007, 08:33:13 PM
You need the ballast with DSII...
Title: Killing Duraspark Boxes
Post by: screaming306 on December 04, 2007, 11:12:38 PM
I am using the factory wiring harness from an 83 t-bird, still using the duraspark 2 ignition system. with a TFI stlye coil. will soon have an msd box helping my needs. The duraspark 2 ignition system is pretty straight foward. i had a few weeks of problems with "no start" till i relized that on the pigtail with 3 wires on the module, i only needed 2 of them (only the red and white, dunno about the green) but when i cut the green wire out, the car starts flawlessly everytime. even upgraded to the 94 and up 3.8 compact starter. fit first time, cranks every time. I do like "old school"  Good luck
Title: Killing Duraspark Boxes
Post by: HAVI on December 04, 2007, 11:33:18 PM
Quote from: blu84302;191070
I belive a TFI coil is a resistance coil.  However I'm starting to think it's not applicable with a DSII box. 

I fried the second box today.  I still have 2 more as backups.  I did buy a ballest and an oil filled coil today. 

Does it matter if I put the oil filled coil on the fender?  I've always seen them on the motor and I'm not sure if it's an issue.  If this module fries then I'm going to mount the ballast and oil coil.


TFI coil with dsII box and setup on a 1986 300 6 in my 79 bronco, works great.  The catch is, the TFI runs at 12v.  The DSII coil steps down to 9 volts in run mode.  It's bypassed to 12v in the start position (key).  Therefor, the TFI coil should be running at 9v when in the run mode of the DSII.  Kinda like backwards compatible, lol. #1 killer on the DSII module is heat.  bolt it down with some 1/4" spacers between it and the fender for better airflow.  Is it possible you have the DSIII that was used for a short time?
Title: Killing Duraspark Boxes
Post by: jcassity on December 05, 2007, 01:11:49 AM
Quote from: HAVI;191121
TFI coil with dsII box and setup on a 1986 300 6 in my 79 bronco, works great.  The catch is, the TFI runs at 12v.  The DSII coil steps down to 9 volts in run mode.  It's bypassed to 12v in the start position (key).  Therefor, the TFI coil should be running at 9v when in the run mode of the DSII.  Kinda like backwards compatible, lol. #1 killer on the DSII module is heat.  bolt it down with some 1/4" spacers between it and the fender for better airflow.  Is it possible you have the DSIII that was used for a short time?


roll out the red carpet havi in explaining the purpose of the ballast.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 05, 2007, 05:13:20 AM
Alright.  I'm confused.  The TFI needs 12V.  The Oil Coil needs 9V.  So, I can still use the TFI coil, just put a ballast to it.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 06:07:00 AM
no, the tfi can run at 9v, but it's made to run at 12v.  It's just a weaker spark.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 06:10:35 AM
Quote from: softtouch;190989
Here is how it should be wired up.

(http://users.rcn.com/jroyle/Dura%20II.jpg)
  See where it says "start bypass" below where it says "ballast resistor"?  That's where your 12v to start is.  In run mode, it goes through the ballast resistor to 9v.  Try to hook up a multimeter to the coil ends and see what the voltage is in start and in run.
Title: Killing Duraspark Boxes
Post by: Chuck W on December 05, 2007, 06:47:42 AM
Quote from: HAVI;191121
  Is it possible you have the DSIII that was used for a short time?


DSIII = EECIII...so most likely not.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 05, 2007, 07:16:47 AM
Alright, so help me some more.  A TFI coil runs 12v (or 9v with weak spark).  If it's made to take a 12 volt load then why not run it at 12 volts.  I'm not hurting coils, I'm killing boxes.  So really the ballast shouldn't be needed since I'm not using a 9 volt coil.

Does that make sense?
Title: Killing Duraspark Boxes
Post by: screaming306 on December 05, 2007, 06:24:31 PM
blu84302 did you try to convert the factory c.f.i. wire harness to work on your combo ???? there might be an extra wire NOT needed that is back feeding to the d.s. module killing it. after weeks of problems i took a harness from an 83 tbird that had the 2BBL CARB V-6 in it. had no problems....with you want i can take pictures of my setup for you. since we both are running the same motor setup in the same year car ??????just trying to help.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 05, 2007, 06:30:51 PM
No, I made my own harness.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 07:09:08 PM
Now that I'm awake....  Let's buttstuffyze what's going on here.  The coil is not the issue.  The TFI coil can handle the 12 volts.  At the ign. box, the red wire goes to the ignition in start and run, and the white wire is to the S on the starter relay.  Not using the white wire eliminates the "retard" at start with the 12 volts.  Not a real big deal.  The pink(maybe some other color for your car) wire under the dash is the resistance wire.  The green wire is the neg. to coil, or tach.  The purple and orange wires are for the pickup/stator inside.  The black is the dist. to box ground.  My question is what type of dizzy did you buy?  Is it designed for the DS2?  I suspect two things.  One:  the ignition box is getting hot....put the spacers in between the fender and the box to get some air around it.  Heat is a killer.  Two:  the dizzy isn't designed to run a DS2 box.  For sake of security, I'd put the resistance wire in and eliminate the guesswork of that being a problem.  One last note, get the module from the JY, as aftermarkets are not as good as the original, IMO.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 07:37:09 PM
For further reading:  You may need to save them and zoom in to read it.  Good luck, I hope this helps.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 07:53:44 PM
might need this page too.  It shows the ballast resistor going from the icm to the coil in the lower left diagram.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 08:00:30 PM
this one shows how to set up the tester/jumper wires for the test on my previous posts.
Title: Killing Duraspark Boxes
Post by: HAVI on December 05, 2007, 08:05:50 PM
See how organized I am, lol.  :wtf:
Title: Killing Duraspark Boxes
Post by: jcassity on December 06, 2007, 04:39:59 AM
Quote from: blu84302;191155
Alright, so help me some more.  A TFI coil runs 12v (or 9v with weak spark).  If it's made to take a 12 volt load then why not run it at 12 volts.  I'm not hurting coils, I'm killing boxes.  So really the ballast shouldn't be needed since I'm not using a 9 volt coil.

Does that make sense?


yoru staring at things from the wrong side of the fence.
forget about "start" ect.
look at the diagram and study the wire coming from the batt part of the coil.  trace it backwards up to the ignition module.

See a resistor inline?  yes.
resistors do what?

they act like a water cut off valve.  the higher the resistance, the less the water (current) flow.
reducing current reduces heat.

now the ballast resister is in series with your module.
some voltage will appear across the resistor but the remaining 6-9vdc will appear at the module.

without the ballast, you have no control of heat, current or voltage.

all this equals heat (in watts).

the coil gets no benefit from the balast being there.  trust me, that coils going to keep on keepin on with 18-24k volts all day long.  Igntion module gets the benefit of the ballast.  Stop talking coils and all the other destractions and start focusing on the heat you are putting on the module.
Title: Killing Duraspark Boxes
Post by: jcassity on December 06, 2007, 04:45:25 AM
Quote from: blu84302;191004
Yeah, it's close to that except I'm not running the white wire for the timing retard.

[COLOR="Red"]Also I'm not using the ballast bypass because it's not nessesary with the TFI coil[/COLOR]. 

I did ground the case out today.  Before it wasn't grounded because it uses a gound in the dissy.  Hopefully that will keep it from heating up alot.


you still did not answer my question on the above in red.
Why do you think this?
Title: Killing Duraspark Boxes
Post by: jcassity on December 06, 2007, 04:53:22 AM
matter of fact,, end this now for yourself. 
go to radioshack and slush out pennies on the dollar for a high wattage resistor of the values you see in the diagrams.

install it

whitness the heat going bye bye on the module.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 06, 2007, 08:35:33 AM
I may not have directed my reasons to you, but I stated that I believed the ballast doesn't have anything to do with the coil.  My reason is better described with this picture.  The red is 12v.  The Ballast is going to the coil not the duraspark box.  I do not see the ballast as being in line to the module. 

I'm not 100 percent sure that I'm reading the diagram right.  But that's why I'm asking for help.  HAVI thanks for those diagrams.  I haven't read through them yet but I will.  I'm definitely wanting to get this problem licked. 

And lastly, I did post that I bought a ballast and a canister coil.  It's in the car along with 2 spare modules.
Title: Killing Duraspark Boxes
Post by: softtouch on December 06, 2007, 05:10:53 PM
From the 84 shop manual:
The resistance of the Duraspark II coil primary is 0.8-1.6 ohms.
The resistance of the EEC IV coil primary is 0.3-1.0 ohms.

It looks like the EEC IV coil may draw more current given it's lower DC resistance.
However coils have another current limiting factor called inductive reactance. This is present while the magnetic field is being built around the coil. I don't know how this compares between the two coils.

The ballast resister limits current flow through the coil but this same current flows through the ignition module via the green wire.
Title: Killing Duraspark Boxes
Post by: softtouch on December 06, 2007, 05:21:42 PM
The ballast resistor dates back to the breaker points days and is a method to compensate for the battery voltage being dragged down by the starter motor. Before the ballast resister and the low voltage coil cars were a real pain to get started on a cold morning.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 06, 2007, 05:27:06 PM
so... When I put a ballast in where should I put it?  just before the coil?  or does it need to be inline with the ignition module also?  The diagram is confusing me.
Title: Killing Duraspark Boxes
Post by: softtouch on December 06, 2007, 05:57:46 PM
I am guessing you are using the hot in both srart and run wire that originaly went to the coil in the EEC IV setup.

Put the resistor inline with the coil but not the module. You will not have the resistor bypass for easier starting.

To wire it like the diagram you will have to find a hot in run only wire and a hot in start only wire.
Title: Killing Duraspark Boxes
Post by: softtouch on December 06, 2007, 06:15:09 PM
I'll do some research on were to locate the wires you need if you want to wire it like the diagram.
The 84 manuals cover the duraspark cars built for export.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 06, 2007, 07:35:54 PM
This is killing me.  Now I'm back to thinking "why do I need a ballast for the coil, how does that decrease heat to the module".  I've made another diagram.  Basically, I'm asking if the ballast is restricting the tach wire voltage which goes to the green wire in the box.  Is the green wire what's causing them to die?

The 2 bad modules failed Low RPM test.  If that helps.

If I have a starter solenoid with the S and the I terminal on it can i use the S for the start bypass? 

Right now I have both the coil and the red module run wire are tied into the same circuit.
Title: Killing Duraspark Boxes
Post by: HAVI on December 06, 2007, 07:48:48 PM
I'd follow this diagram instead:
Title: Killing Duraspark Boxes
Post by: HAVI on December 06, 2007, 07:50:04 PM
oops, forgot the pic, lol  Here it is:
Title: Killing Duraspark Boxes
Post by: blu84302 on December 06, 2007, 07:54:44 PM
Alright.  That looks ALOT simpler.  I've got to go to work but soon it will be wired up like that.  I'll do as jcassity said and "end this for good".  Only one way to find out and that's to throw the ballast in there. 

Thank you jcassity, HAVI, and Softtouch.  I'm sorry that I asked for help but was stubborn to accept the help that I was given.  Sometimes I can be closeminded.

-Johnny C
Title: Killing Duraspark Boxes
Post by: HAVI on December 06, 2007, 08:01:27 PM
No problem here, the end result is to just get it right.  You don't want to be ruining ICM's everyday, lol.  Good luck.  Oh, and I'll be rewiring my car's ignition in the future, too.  In about 3 years at this rate, lol.
Title: Killing Duraspark Boxes
Post by: jcassity on December 06, 2007, 10:52:29 PM
your fine,, the only thing that has happened on this thread is progress.  In addition, it makes a good sticky to!  post back results and if its all working fine ,,,****AND*** lasts,, then its sticky worthy.

Im linking this thread to my DIY LINK.


ALSO!!,, make sure you take in consideration the wattage of the resistor you buy.  I would buy a big fat one.  Big fat resistors mean they can take the heat.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 08, 2007, 07:13:31 AM
If all else fails, I've come across another option.  GM's HEI module, with a TFI coil, and Duraspark Dissy.

http://www.bronco.com/cms/node/25 (http://"http://www.bronco.com/cms/node/25")

(http://www.bronco.com/cms/files/hei_pic2.gif)
Title: Killing Duraspark Boxes
Post by: blu84302 on December 24, 2007, 04:24:47 PM
Alright, So far I've still been running this same duraspark box.  This is the third one, and it's an autozoner brand. 

She hasn't failed me for a few weeks so i haven't had the urge to put a ballast inline.  So that kinda throws out the whole "needs" a ballast thing.  I'm going to keep running this box like it is til it gives me trouble.
Title: Killing Duraspark Boxes
Post by: blu84302 on December 26, 2007, 07:31:35 PM
Update:  Put the freaking ballast in!  That's the only way to be sure.  Just got done being stranded for 2 hours.  Wasn't fun.  Went through 3 boxes and 1 coil.

So the ballast acts as a capacitor and that'll keep voltage spikes down.  So I figure the reason i just blew three boxes and a coil was because of a voltage spike or something.  Anyway, changed the coil and I put the ballast on.  I'll let you know if she gives me anymore trouble.