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No voltage at coil
https://slantsix.org/forum/viewtopic.php?t=29797		 Page 1 of 1
Author:  00spy [ Sun Jun 29, 2008 1:08 pm ]
Post subject:  No voltage at coil
I checked my coil for voltage , and it did not show it having any.
I then checked the coil using the negative wire that was on the old coil with the lean burn system and it showed good voltage.
I then checked it for voltage with the ground wire for the HEI module , and it had voltage .
I checked the voltage with the C terminal on the HEI module and had no voltage.
My question is can I just hook up the old negative wire from the lean burn system to the coil, and that would solve the problem , or is something wrong with my module ( new GM)

Thanks Dave
Author:  00spy [ Mon Jun 30, 2008 2:39 pm ]
Post subject: 
Can anyone answer my question? I read to leave the negative wire that was on the old coil off ,when doing the HEI conversion .I thought that the wire of the c terminal to the negative post would ground it . I don't want to screw anything up. would it be right to just hook the negative wire that was on the old coil to the new coil. This maybe a stupid question , but I would like to know for sure.


Dave
Author:  LUCKY13 [ Mon Jun 30, 2008 3:34 pm ]
Post subject: 
No thats not what you need to do, hook the wire from coil neg to the C . Is the system not working? You might not have the module grounded good or the pick up in the dizzy may be wired in reverse (switch the wires if so).



Jess
Author:  00spy [ Mon Jun 30, 2008 3:47 pm ]
Post subject: 
Thanks for your reply.
I guess the module is grounded good . I have it grounded to the alternator ground. Like I said ,the coil shows voltage when I touch the ground wire on the module ,but not when I touch the wire for the C terminal.
I will definetly try to switch the two wires for the distributor next. I thought I have found an article that should which wire goes to which , but I guess all you read on the internet is correct.
Thanks again
Dave
Author:  00spy [ Mon Jun 30, 2008 4:18 pm ]
Post subject: 
Well here is the deal I swapped the wires on the distributor pickup and still the same.
I can touch any kind of ground on the truck and it shows voltage on the coil, all except the negative post on the coil or the C terminal on the module.
I guess I need to have the module checked out I guess.

Dave
Author:  Charrlie_S [ Mon Jun 30, 2008 5:41 pm ]
Post subject: 
If I remember correctly, you will not be able to use the factory wires to the coil, when the vehcle was a lean burn. I would have to dig out a wiring diagram to be sure.

Is the lean burn computer still on the vehicle, and wired up?

You should have a dark blue wire that went to the original coil hookup. Connect this wire to the coil + and the B terminal of the module.
Negative coil terminal goes to the C terminal of the module.
Male pin on the distributer connector goes to pin W on the module
Female cavaty on the distributer connector, goes to pin G of the module

These are the only wires that should be connected to the ign circuit, except for a tach if you have one, the trigger should go to the coil Negative.

I hope you are using a single pickup electronic distributer with a vacumm advance pot.
Author:  LUCKY13 [ Mon Jun 30, 2008 9:37 pm ]
Post subject: 
I dont understand why your looking for voltage on the negative side of the coil anyway.


Have you tried to start the car with its hooked the way it should be (C to coil - ) ? Or are you just stopping when you dont find voltage on the negative side of the coil ?


The C terminal will trigger the coil ( Ground it, which will complete the circuit) when you crank the engine over if you have voltage on the + side of the coil ( which is the blue wire CharlieS meantioned). The modual does this ( grounds the coil ) when it picks up the signal from the distributor when you crank the engine.


If its not starting for you it may be possible that you only have voltage to the + side of the coil when the key is on and not when in the start possition. RUn a hot wire from the battery striaght to the coil + side and see if it starts if its not been working for you (just as a test).



Here is a link that shows the wireing to do this on a Mapor and it shows the ballast resister wiring also if needed.

http://duster318.freeservers.com/tech/hei.html


Jess
Author:  00spy [ Tue Jul 01, 2008 2:05 pm ]
Post subject: 
Maybe Im just an idiot here ,so to check the voltage for the coil , you use your multi(volt)meter and touch it to the pos. side and neg. side of the coil .when I do that I get no voltage . but if I touch a ground point somewhere else besides the neg. terminal on the coil it shows voltage.
So maybe what Im trying to find out ,is that what its suppose to do.I thought it should show voltage by using the coil terminals.
Im not trying to be confusing. Is what I am saying sound right.

Dave
Author:  00spy [ Tue Jul 01, 2008 2:34 pm ]
Post subject: 
Jess
Ok so the the C terminal triggers the neg side of the coil when it is cranked and grounds it, that is why it does not show when I check the two terminals on the coil with the switch on. You have to take in consideration that I am from North Carolina :) .
Thanks to Charlie also

Thanks
Dave
Author:  LUCKY13 [ Tue Jul 01, 2008 4:29 pm ]
Post subject: 
LOL,, I dont know if you switched the pickup wires back from where you swapped them doing test, if there still swapped remember to switch them back.



Jess
Author:  Charrlie_S [ Tue Jul 01, 2008 4:37 pm ]
Post subject: 
Put a volt meter/test light from the plus terminal of the coil to ground. Should have 12 V power with both key on and engine crank.
Put meter/light on negative terminal of the coil to ground.
Should have 12v power with key on, no crank. and pulse 12 to 0 volt (test light works better here. blinks) in engine crank.
If you have these conditions, you should have spark.
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