Coil getting hot when car is off?
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 1,196
Likes: 47
From: Scarborough Maine Fredericksburg VA
Coil getting hot when car is off?
First this is a big day for me as I fired my 70 LT-1 after a few years of rebuild. I built a 70 LT-1 engine using all correct parts including a NOS short block from 70. Pictures coming.
Anyway - when I hooked up the battery I could feel the coil and wiring going back to the control box getting hot. Everything is new or rebuilt. The distributor was done by TI specialties along with the coil. The module was redone with the new style board. Also all of the wiring is new.
The car fired right up first crank and the coil didn't seem to heat up with the car running. Any thoughts? Bad ground somewhere?
Anyway - when I hooked up the battery I could feel the coil and wiring going back to the control box getting hot. Everything is new or rebuilt. The distributor was done by TI specialties along with the coil. The module was redone with the new style board. Also all of the wiring is new.
The car fired right up first crank and the coil didn't seem to heat up with the car running. Any thoughts? Bad ground somewhere?
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 1,196
Likes: 47
From: Scarborough Maine Fredericksburg VA
Thanks, I took out an MSD set up so they may have changed the wiring from the starter.
Weird thing is that since I started the motor it has not happened again. The engine starts right up and the coil now stays cool. No idea why it did it when I first hooked up the battery.
Weird thing is that since I started the motor it has not happened again. The engine starts right up and the coil now stays cool. No idea why it did it when I first hooked up the battery.
Melting Slicks
Joined: Oct 2012
Posts: 2,156
Likes: 273
From: Dunedin NZ.
Question is, are you running points ignition? If you are and there is power to the coil with the key off the coil will get hot but only if the points happen to be closed. You need to put a meter or test light between the positive wire to the coil and to ground and verify that there is no power there when the key is off. You can damage the points and or coil if you leave it with power there when the engine is not running as well as flatten the battery of course.
I'm not up with the play with what happens to the electronic modules in the same circumstances!
I'm not up with the play with what happens to the electronic modules in the same circumstances!
Pro
Joined: May 2011
Posts: 722
Likes: 58
From: Karlsruhe (Germany)
Your Ignition switch may have been in the "on" position the first time 
If you had a wrong wiring with always voltage on the TI you won´t be able to turn the engine off with the ignition switch.
If you had a wrong wiring with always voltage on the TI you won´t be able to turn the engine off with the ignition switch.
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 1,196
Likes: 47
From: Scarborough Maine Fredericksburg VA
No points as it is the stock LT-1 ignition.
The key may have been in the on position. I wasn't aware that would energize the coil that way but it seems the most reasonable explanation given it hasn't done it since the initial start up.
The car has been setting for around 4 years. The door buzzer also now goes off when ever you open the door although I don't think that is related and is a different fix. I think having a key in the ignition for the past 4 years has the lock cylinder a little tight. I tried some WD 40 but will probably end up taking it out to fix it.
The key may have been in the on position. I wasn't aware that would energize the coil that way but it seems the most reasonable explanation given it hasn't done it since the initial start up.
The car has been setting for around 4 years. The door buzzer also now goes off when ever you open the door although I don't think that is related and is a different fix. I think having a key in the ignition for the past 4 years has the lock cylinder a little tight. I tried some WD 40 but will probably end up taking it out to fix it.
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 1,196
Likes: 47
From: Scarborough Maine Fredericksburg VA
I wondered about the resistor as one wiring diagram showed the black wire from the module going into a white wire and then onto the coil. The wiring harness I bought had the coil connector at the end of the black wire to simply hook to the coil so that is what I did. A friend told me that his Camaro had a white wire that acted as a resistor?
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Race Director
Joined: May 2006
Posts: 18,742
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this is the wiring diagram as you can see the white wire going to the positive post on the coil has a section that indicates it is a resistor wire
http://tispecialty.com/articles/66-71diagram.htm
http://tispecialty.com/articles/66-71diagram.htm
Last edited by MelWff; Aug 26, 2014 at 04:41 PM.
Thread Starter
Burning Brakes
Joined: Oct 2002
Posts: 1,196
Likes: 47
From: Scarborough Maine Fredericksburg VA
Thanks, the diagram is very helpful. I had TIS do the rebuild on the dist as well as provide the coil and some wiring. I ended up using the wiring from the harness I replaced and will now go back and look to see if it is different then what TSI sent. I did look when I put it together although maybe not close enough.
Race Director
Joined: May 2006
Posts: 18,742
Likes: 2,583
I would contact them and find out what the primary and secondary circuit resistance on the coil should be. If not within specs the coil was damaged by applying full voltage to it and would account for the heat you felt.
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.