Duraspark II/HEI conversion failed - Ford Truck Enthusiasts Forums


Duraspark II/HEI conversion failed

Old 08-07-2011, 10:40 AM
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Duraspark II/HEI conversion failed

I will try to give the shortest version of this that I can. The engine this refers to is the good ole 300 i6. Yesterday I attempted to place a 4-pin HEI module on my truck, because the ballast resistor I had been using on my Duraspark II setup burned in half. Many folks are talking about the HEI setup, and I have heard few negatives about it. Here is my story, perhaps someone can help.

The schematic I used is as follows:

Module pin details:

B = HEI module power in and coil + terminal power in
C = HEI module to coil - and tach
W = HEI module to DSII stator orange
G = HEI module to DSII stator green

I wired everything up with the proper terminals using this exact arrangement except my B terminal connection does not feed off of the coil + terminal as a bus location. Rather, my ignition switch feeds both the module and the coil + from a T-junction right outside the firewall (shouldn't matter, my duraspark was like that too and lots of chrysler boys do it that way).

Specific parts used in the experiments:

BWD control module CBE4Z from Advance Auto (because they didn't have any of the better ones in stock)

14 gauge primary wires of different colors

crimp connectors: 1/4" female on pins B, C, and W and 3/16" female on G

Cardone reman DSII distributor that was put on the truck over a year ago for a 1981 F100.

bread loaf pan was drilled such that the 8/32 screws used for the module actually screwed in. This was to be my makeshift heat sink, because it is dreadfully difficult to find a spot to mount the HEI on my 86 F150, and porper heat sinks were not to be found in BFE where I live. Lack of resources and creativity are close cousins.

These were the initial pieces I selected to run the experiements, with the idea that I would get a better heat sink and pay shipping costs for one if it was worth my time.

The experiments:

The module was mounted to the bread pan which was in turn bolted to the plastic inner fender well just between the DSII module and the wash/radiator overflow bottle. The wiring was set up as per the diagram above with only the mentioned T-junction arrangement of the supply voltage circuit as a midification. Everything looked neat and proper, so the key was turned. A no-fire condition was confirmed by a spark tester following several disappointing attempts to fire the engine. A voltmeter was hooked to the supply voltage circuit to determine potential vs. key position, just to be sure (I already knew this was fine due to the duraspark conversion I did from EEC-IV the previous year, but better safe than sorry). I also did other critical voltmeter tests.

Key position test:

Run position = 12.6V @ module B + and 12.6V @ coil +
Start position = exactly the same as run

The basic primary voltage was fine and active in both critical key positions.

Module power and ground:

The negative voltmeter lead was touched to the screw where the black wire to the distributor base was connected, and the positive lead to the module B+. 12.6V

The module was powered up and grounded.

Module power and ground rework:

direct battery terminal + and - connections were run to the module with test wires and gator clips. The coil + was also included. Cranked it and no spark.

Duraspark II module test run: To inspect the integrity of the orange and purple stator connections, the original DSII module was hooked up with the exact same wires that were in place on the HEI module. The 4-pin DSII module plug recieved the wiring from HEI in this specific fashion:

HEI C terminal to coil - was hooked to DSII green lead
HEI B terminal to coil + was hooked to DSII white power in
HEI W orange lead was conncted to DSII orange stator lead
HEI G purple lead was connected to DSII purple lead
HEI distributor ground was hooked to DSII black lead with a gator clip

Key was turned and the engine fired up and ran perfectly within 1/2 second.

HEI double ground: a whole was drilled in the cake pan which tested 0.00 ohms in a continuity test to determine conductivity. The whole was connected by a lead to the battery negative terminal to provide ground connectivity across the entire back of the HEI module (assuming that the heat sink compound is conductive. Again no spark.

HEI module replacement: The module was taken back to Advance and swapped for a new one. Again, no spark.

Conclusion: The BWD HEI module cannot communicate with the cardone reman stator to complete the ignition firing circuit.

Does anyone know what the hell is going on here? Have I missed something? Any input will be appreciated.

I hooked the DSII back up, because the truck is my daily driver, and I cannot be without it. It still does not have the ballst resistor. The coil I am using is this:

MSD street fire (PN 5527)

This coil is available for all the later model TFI and EFI Ford motors that didn't use ballasts, and the input voltage is rated for 12 V. To me that means that the ballast is not necessary, because the coil has its own built in resistance. The DSII module runs a constant 12 V anyway, so I figure I might just say the hell with the HEI mod as long as this coil is going to survive a no-ballst condition. There are tons of confliciting reoprts on the internet in regard to whether or not coils and modules for DSII live through the no-ballast scenario, but it seems to me that if the coil has its own internal resistance built in, then there is no need to worry since firing power is going to be normalized to the same thing. That being said, what thoughts do we have out there regarding this topoc in general? Is it even worth it to bother with the HEI since it didn't work for me, and the DSII is a fine ignition anyway? Thanks folks.
Old 02-14-2014, 09:23 PM
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I found this through Google on a simple search about duraspark to hei conversion.

It should be deleted.

I doubt this will help the original poster but for those that read this after the fact(such as myself) there are a couple problems.

The main problem I see is that the white wire is connected to the power in for the hei module. I know nothing of hei and little of duraspark (hence my search) but for duraspark the white wire is hot only in start. Meaning if you wire it this way you will lose power to your module once the key is released from start to run.

This very well could have been the issue with the original poster.

The other issue with this post is the ballast resistor. It needs to be in place while running a ds2. As far as I know the coil will get hot and can fail at the higher voltage. The problem can after time cause the module to burn out from excess heat. The red wire to the ds module should be 12 volt run/start. The coil should receive 12 while in start but be less in run as it should go through the resistor. This aids in starting. Again this may not be a start/no start issue, more wear and tear.
Again I'm no expert but it concerns me that this post shows up so readily from a simple search. Maybe there is no problem with the original posters wiring config but this jumped out at me. Probably best to simply be deleted or ignored.
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