20$ ignitor fix: Joe Bialy's writeup (HEI MODULE)

[Goatcrapp]

There has been enough discussion of this topic on MX6.com to warrant recreating the info here for quick reference. I've pasted a selection of pertinent posts from the probetalk thread, but there is a ton of great information over there - this is just a basic rundown.

The following is used with permission from the author

Taken from this thread ON PROBETALK - if you wish to view the surrounding questions and comments by users

Thanks Joe for the excellent research and writeup!
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This mod will save lots of people lots of money. It is also a good basis for real ignition upgrades.

After 173,000 miles, my ignitor finally bit the dust. Not wanting to spend $224 for another one, or an equal amount for a feeble MSD, I wired in a $20 (Wells #DR-100) generic GM 4-pin HEI module instead.

In a nutshell:

The ECU's trigger output wire (BL/O) feeds the HEI's pin 'G'.
Ground the HEI's pin 'W'.
Ground the HEI's base.
HEI's pin 'B' taps into the +12V dizzy feed wire (BK/P).
HEI's pin 'C' taps into the coil's primary wire (Y/G).
Remove the internal strap connecting the old ignitor to the coil plug center terminal.

I mounted the HEI module on a bracket next to the LH headlamp.

If $20 is too steep, head to the wreckers and get a used module for a buck or two. Almost every GM car from the mid 70's to the mid 80's has one.

If you don't want the stock coil, it would be just as simple to use an external coil if you add the extra terminal to the cap for it. Lotsa places have hi-perf. HEI modules and HEI specific hi-perf. coils too.
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Here's a picture of a typical 4 pin module. This one is in a V-12 Jaguar but it is the exact same part I used and it shows the pins clearly marked:

http://www.erlandsson.se/jaguar/ab14amplifier.jpg

The GM part # is 10482820

Niehoff part # DR400

Wells part # DR100 (what I have)

If the parts guy doesn't know what a 4 pin module is or can't cross reference these part numbers, then tell him its for a 79 Chevy 350 Caprice, that should be the same part.

With the right coils, this module will spark a 12 cylinder 12.5:1 CR Jaguar to 7000 rpm, more than enough for anybody's V-6. Summitt and Jeg's have lots of HEI stuff that's even hotter than this stock stuff.

I took some pictures of my set up, I'll post them somehow on the web for all to see. Apparently I can't post attachments directly to P-T.

After driving hard for an hour this morning, I checked the temperature of the module, its cool as can be. I think thats because the Probe coil's primary is around 1 ohm and the module isn't working very hard controlling current. It normally runs very warm when it is hooked up to a 0.4 ohm HEI coil.

The bad part about ignitor failure is that it won't normally happen in your garage on a Saturday morning. It'll be at 2am in BFE during a storm. This mod is so easy, you could throw these parts, prewired, in your glove box and be ready for it when it happens.
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Here's a link to some pictures of this mod which shows the tie ins at the distributor and where I mounted the module:

http://www.picturetrail.com/

My member name is "heiprobe"

My car is a 94 PGT. $13 is the cheapest yet!
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wiring diagram

http://ryand2.cjb.net/my%20pictures/...itor/hei01.gif
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connecting to external coil:
http://home.comcast.net/~mmunoz70/z/...t-HEI-Coil.gif

An external coil on a '94 like mine is pretty straightforward:

Besides the new coil, you'll need a new 1,000 ohm resistor to feed the tach because the Probe's old coil has this resistor built into it.

1) Do not plug in the 3 pin connector to the disty at all.
2) Pin #1 Black/Pink (power) will be new coil (+) and HEI "B".
3) Pin #2 Yellow/Green (IG-) will be HEI "C" and coil (-) and one side of the new 1,000 ohm resistor.
4) Pin #3 Yellow/Blue (tach output) will get the other side of the 1,000 ohm resistor.
5) Big connector pin 6 Blue/Orange goes to HEI "G" as before.

1,000 ohms is Brown-Black-Red, 1/2 watt will be fine. $.50 at Radio Shack.

The 3 pin connector (C170) is numbered 1-3-2. Not 1-2-3 as the incorrect All Data connector diagram shows. The correct order is:
1= circuit 2 Bk/P power
3= circuit 731 Y/Bl tach output
2= circuit 732 Y/G tach signal (ignition ground) or "IG-" on the DLC.

The faded wiring on my car makes it impossible to tell Y/Bl from Y/G. They both look like Y/G to me. You can be sure you have the right Y/G (IG-) wire by checking for continuity between pin #2 of the disty plug and the (IG-) pin of the DLC-its the same wire.

On to the '95:

You will need to do continuity checks to see where the three pins of the old ignitor go to. I suspect its electrically identical to the '94, just repackaged. If that's the case, then it will connect the same way. You don't have the strap to remove like the '94, but instead, you'll need to cut the corresponding pin on the ignitor. One ignitor pin will mimic the "G" function, one will mimic "B", and one will mimic "C" on the HEI diagram.

Or, screw the old coil and use an external one. Then you can forget about the ignitor all together. Just make sure the three pin C170 is the same configuration as the '94 is, and use the same Blue/Orange trigger wire on the big connector just like on the '94.
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(pics for wiring to 95+ vehicles, thanks, Omaha95PGT!)
'95+ distributors are different in their layout. I had posted up some '95+ disty anatomy pics on the old PT, but I'll repost them here for the continued development of this mod.

Personally, I'd like to see the advancement of this mod to include not just a simple repair for blown ignitors, but to include the addition of a "hot module" (performance HEI module) and the wiring of a high discharge coil. Sort of a simpler and less expensive alternative to the MSD setups.

Joe_Bialy, can you post up a wiring diagram that would include an external coil?

Here are the '95 disty pics:

http://home.comcast.net/~mmunoz70/z/cams05.jpg
http://home.comcast.net/~mmunoz70/z/95disty01.jpg
http://home.comcast.net/~mmunoz70/z/95disty02.jpg
http://home.comcast.net/~mmunoz70/z/95disty03.jpg
http://home.comcast.net/~mmunoz70/z/95disty04.jpg
http://home.comcast.net/~mmunoz70/z/95disty05.jpg
http://home.comcast.net/~mmunoz70/z/95disty06.jpg
http://home.comcast.net/~mmunoz70/z/95disty07.jpg
http://home.comcast.net/~mmunoz70/z/95disty08.jpg
http://home.comcast.net/~mmunoz70/z/95disty09.jpg
http://home.comcast.net/~mmunoz70/z/95disty10.jpg
http://home.comcast.net/~mmunoz70/z/95disty11.jpg
http://home.comcast.net/~mmunoz70/z/95disty12.jpg
http://home.comcast.net/~mmunoz70/z/95disty13.jpg
http://home.comcast.net/~mmunoz70/z/95disty14.jpg

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Thanks EasyBOB for the following!
http://f2.pg.photos.yahoo.com/ph/ch...m/ph//my_photos

How to hook up an MSD 6AL + Blaster 2 to a ZE disty using the HEI ignitor.

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Check out the thread(s) for more info - Lets not clutter this thread with questions that have already been asked =)

another BIG thumbs up to Joe.