Can anyone explain how to wire a two terminal external coil to a small cap hei? I thought I did it right but I have power to both the pos. and the neg. terminals on the coil. I have original pink wire to positive terminal on coil, then another pink wire coming from the coil to the dist. Same with the original white wire, hooked to neg. term. on coil then another white wire from that term. to the dist.

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Sorry, I'm no artist, this is what I have now.

 

....................... The two wires between the distributor and the coil should be the only wires used ............

 

 

ol' keystring has the knack for computers!l

you probably know that you need a 12V wire to the coil, without the built in resistor. the HEI comes from the 12-14V, though it will run on 6v. I have seen more than one HEI with the original resistor wire from ignition.

 

While I will be the first to admit I can't make heads nor tails from electrical diagrams, it looks to me as if what you are showing is what I have, power to positive side of coil, then from that terminal to the power feed wire on the dist. Then the tach wire from the firewall to the neg. side of coil, then from that term. to the tach wire on the dist. Also, I am using the small cap hei which has a 4 wire connector and a 2 wire connector.
After doing some checking last night I think I have the proper way to do it, I will try in a bit & see if it works.
Thanks Keystring.

 

While I will be the first to admit I can't make heads nor tails from electrical diagrams, it looks to me as if what you are showing is what I have, power to positive side of coil, then from that terminal to the power feed wire on the dist. Then the tach wire from the firewall to the neg. side of coil, then from that term. to the tach wire on the dist. Also, I am using the small cap hei which has a 4 wire connector and a 2 wire connector.
After doing some checking last night I think I have the proper way to do it, I will try in a bit & see if it works.
Thanks Keystring.
This is what I am going to try,,
[IMG][/IMG]

 

Your last drawing is a fail

No guru here, but it's a coil, so until the module applys ground, there will be 12v on both sides of coil, as it's a coil.

 

Open up your large diameter distributor. You will see that the pink wire goes to the power in. Then the white wire goes to the tach.
THEN THE 4 PIN PLUG OPERATES THE MODULE.
When you separate the coil as in the small dia. dist, the power still goes to the coil, and the ground goes to the ground wire, the black with the red tracer is the ground for both the coil and the module.
But when you separate them,as in the small dia. dist, the coil ground is the trigger through the module. So the black/red should go to both the module and the coil from the dist.
For instance, if you had it wired the way you show, the coil will get only one pulse, period. the key on pulse.
If the module in the distributor is turning off and on the ground to the coil, it will be a sequence of timed pulses, which will build and collapse the field inside the coil.
So in the big distributor, the module can run the ground. In the little dist, the module is on the aluminum plate under the dist. and also runs the ground. So take the power off the coil to the distributor, and just have the power go into the coil. use the wire from the dist. to the coil to get timed sparks.
In your diagram, the orange wires have to be on the same terminal.
You have probably zapped the module by putting power on it in too many places.
So take it to Auto Zone, and ask them to check the module. They have a checker, and they will check it for free.

 

If you notice, in the diagram, you have only one (1) negative connection to the coil. Not two (2).

That one connection goes to the control module. The TACH connection is not a 'ground', but a negative 'pulse' for the tach sensor and turns the coil field on and off. It should not be grounded,...

'B' and 'C' are the connections in the plug you removed...

Either cut the old connector from the harness (NOT RECOMMENDED in case you want to change back) or go to a junk yard and cut one from a
GM car to use.

Wire up the pigtail to the coil and plug it in to the distributor.

 

Yep, I did have a dead module, I'm going to start all over in the morning & set it up like you describe, I'll keep everyone posted. Did I mention that I am a dumb **** when it comes to electricity?

 

It's 12:21 A.M. and I have spark!! I got a wild hair & went back out to the garage to try some of your suggestions. I had the wiring right the first time but the dead ignition module was the culprit. Just because a part is new doesn't mean it is good. At least my diddling around didn't fry it, it was dead before I got started. I also found out the distributor is off so tomorrow I will pull it & drop it back in the correct position and we should be off to the races.
Thanks to all of you, especially Coupeguy, he has been with me by pms from the start and his advice was much appreciated.

 

http://forums.corvetteforum.com/c4-t...r-hsr-mod.html

 

I was just about ready to go get the double connector coil and the pigtails to wire mine up that way but I got it straightened out and I have a nice bright blue/white spark now. So, once I got spark it still wouldn't start. To make a long story short, I have an ecm which is not firing the injectors. This is what I get for buying a used ecm. A new ecm will be here tomorrow morning so hopefully I can get it fired up by midday.

 

How are you dealing with VATS ?
Is the module sending the reference signal to ECM ?

 

No vats on the 85 Dan, everything else works so would the newer ecm be giving me the loss of injector pulse? This is one thing that was not covered in the repinning instructions. Also, I did all the tests in the fsm to see about a problem in the wiring and all proved out to be working as it should except the power to the injectors. All circuits are solid and complete. My experience with vats was that if it will not even allow the starter to crank the engine and I don't have that problem.

 

The ECM itself won't but the tune on the chip inside it might
VATS is a computer function ; not a car / year specific function
What memcal / chip / prom ( tune) are you using ; if a stock one most likely still has VATS enabled taking out the injectors only as '86 asked above

But your car is not setup for VATS to take out the starter without you rewiring the starter circuit so not relevant

 

DAMN! Why doesn't somebody tell me this?? OH, you just did.
Well, that is most likely the problem then, the prom is for an '87. Thanks rodj, and thanks Dan for catching this.

 

Two choices
A custom tune with VATS disabled
or one of these
http://www.bakerelectronix.com/products_vats/
to supply the fuel enable signal direct to the ECM.
Then it doesn't matter what memcal you are using as the ECM is always seeing the correct input signal from the non existent VATS module

Other VATS signal generators on that auction site for as low as $15
http://www.ebay.com/itm/GM-VATS-or-P...c89c8f&vxp=mtr
(Can't speak for either of them as I have VATS deleted in the tune)

 

Thanks rodj, I have to get a custom tune anyway for my combo, I was just trying to get the engine fired so I could set timing etc. I knew the stock chip would not support my engines needs but it would have been okay for the minor adjustments I needed to do.

 

A big thank you to all of you who helped me on the wiring & other issues discussed in this thread, you guys are all class acts and I am very grateful to all of you.