CorvetteDave01

I rewired my converted, hall effect HEI distributor (1976) for a Mallory hall effect, small cap/external coil setup yesterday. The only wiring issue is in respect to the external coil and it is the same issue converting with a carb setup.

The HEI distributor has this 5 wire setup looking down and from the drivers side. Obviously there are only 2 posts for the external coil.

C- / GND / B+
Tach / Battery


Where does the brown (labeled C-) wire for the HEI coil go? And where does the black (labeled gnd) wire for the HEI coil go?

What I have done currently is the following, but I want to double check things with you guys.

1. C- and Tach wires went to the Negative side of the external coil.
2. GND went to a chassis ground
3. B+ and Battery or Power wire went to the Positive side of the external coil.

gkull

Will any of these work?

http://www.centuryperformance.com/mallory/wiring.asp

CorvetteDave01

Thanks George, I looked through all of those diagrams and they really don't show me what I need I don't think. I really just need to know about the stock, '76 brown wire and the black wire that plugs into the HEI coil (via a 3 connector clip). I'll keep looking.

gkull

I've got to run in to a job site right now. I've got a Haynes Vette book and I will look up the colors in the wiring section later on for you

69427

Other than a possible size reduction, I am perplexed why you would change from a reluctor pick-up system (with variable dwell) to a Hall Effect system.
Your wiring description looks correct. C- is the line hooked to the negative side of the coil, and runs to the module switching transistor (or points in older systems), and provides the flyback voltage for the Tach signal.
Ground is obviously ground. I assume the new module has a connection to this point.
B+ is the (low resistance) positive feed for the module, and, in premium systems, also the feed for the coil. Lesser units require a ballast resistor in the line between B+ and the coil C+ terminal.

CorvetteDave01

I converted to a hall effect distributor because it's an EFI system for a modified Edelbrock Proflo. Used to use a gutted HEI setup with a conversion kit for the hall effect setup.

I bought a Mallory/aftermarket distributor that is made for the EFI setup, has the connection right etc. Plus it is a small cap and new. however, I need the external coil setup with it.

69427

Fair 'nuff.

CorvetteDave01

OK, I need help. Coil isn't giving any spark and heated up in about 5 minutes with the key on (10 seconds of cranking). Also the ignition box heated up.

Obviously my wiring isn't working, but not sure where to begin.

69427

As much as I dislike most of the aftermarket ignition stuff out there, I dislike seeing someone having problems even more. I can offer a few generic suggestions, then just let us know what you see.

1) As I mentioned earlier, does the system require a ballast resistor? (Most aftermarket systems are crude enough to require one. HEI does not need one.)
2) What is the resistance + to - of your coil? (I'm trying to determine how much current is flowing into your module.)
3) You mentioned no spark. You can test the coil by leaving the + side hooked up to B+, and then use a short jumper wire (on the coil - lead) to tap (just tap, don't hold down) the other end of the jumper to ground. This will simulate the operation of points or the module. Does it make spark out of the high voltage terminal?
4) Can you put some sort of lamp/LED&resistor load in place of the coil to see if the module is switching, or just stuck on?

Just trying to narrow down the problem. Let us know what you find out. Good luck.

CorvetteDave01

OK, I uploaded a bunch of pics. I now have switched back to the old HEI distributor (converted for hall effect for the edelbrock proflo efi setup).

No spark now either AND I am getting an error message on my EFI control module. "Warning high/low voltage".

Thanks are getting worse I think...

CorvetteDave01

more pics

CorvetteDave01

Also, I did a voltage test with the key on. Battery was 12.2V and the big red Battery power wire to the coil was 11.88V. Think this system needs 10.5V to operate, so I'm guessing the problem lies between the main harness power wire and the ignition box. Going to relook at the timing too because the distr cap is all awkward looking, might have it off by a couple of teeth.