ignition wiring question
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ignition wiring question
Posted: February 24 2006 10:41 AM
 
John Byrd (aka jcbyrd) [ View ] [ haliberty@gocats.uk.com ] [ Car Ads ] [ Blogs ]
Liberty, Kentucky
 
a few months ago I had a problem with the ignition on my car (39 Chevy). It quit running. power wire burned in two inside the wiring harness. as a fix I ran a power wire direct from the fuse box on a circuit marked fused ignition (old GM glass fused box) dirctly to th coil (GM HEI ) . It works fine but I was wondering if I should go to the trouble of wiring the power from the ignition switch as original ? (Lots of trouble to get to the Switch) what do you guys think? thanks
 
 
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Posted by halfbreed  -  02/22/2006 05:05 PM

yes this will be fine if you take a test light and check the wire on the starter solenoid should only have power during start up not run so as soon as it starts up the only hot is the one on ignition.
halfbreed [ View ] [ Email ] [ Blogs ] [ Car Ads ] charlotte, North Carolina
 
Posted by jcbyrd  -  02/22/2006 02:24 PM
if I run a wire from the terminal on the solenoid to the coil (HEI) that will mean I have two wires to the coil, one from the ignition switch(run) and one from the solenoid(start) . is this OK? I know this was done on old standard coil ignition setups with a ballast reducer but want to make sure it is OK to do on HEI ignition setups? do not want to burn something up with two 12 volt sources to the coil. any help wiould be appreciated.
jcbyrd [ View ] [ Email ] [ Blogs ] [ Car Ads ] Liberty, Kentucky
 
Posted by jcbyrd  -  02/24/2006 10:41 AM
I went ahead and installed new wire directly from ignition switch to the coil instead of the wire I had run from the fuse box when all of my ignition problems started. also installed a 4ga. ground cable from a bellhousing bolt at the starter to the frame. starter now seems to spin a lot faster and car starts instantly.
jcbyrd [ View ] [ Email ] [ Blogs ] [ Car Ads ] Liberty, Kentucky
 
Posted by crash12888  -  02/22/2006 07:33 PM
JC, It sounds like you changed the solenoid to get the second terminal. Just run a wire from the second terminal up to the coil and it will be fine. The run circuit will actually backfeed 12 volts back down the wire to the solenoid from the coil once it starts so if you put a meter on it while it's running, you will get a reading but that is not a problem. Should notice the motor starting quicker. No matter how many 12 volt wires you run to something it's still 12 volts. Mitch
crash12888 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Chesterfield, Virginia
 
Posted by Crazyhorse Rod Shop  -  01/05/2006 09:10 AM
jc , i would be more concerned why the wire burned. does'nt sound good to me. sounds like a mojor overload.
dont poke the porchdog........he bites [ View ] [ Email ] [ Blogs ] [ Car Ads ] BLUFF DALE, Texas Charter Member since March 2003
 
Posted by crash12888  -  01/05/2006 08:11 PM

jc, there should be two small terminals on your starter solenoid along with the two big lugs. One from the ignition circuit to energize the solenoid and starter that seems to be working. The other terminal feeds a good 12volts to the ignition coil when the key is in the start position. Once you release the key that circuit drops off just like the starter and the coil is feed from the run supply. Check that wire for breaks or bad connections.
crash12888 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Chesterfield, Virginia
 
Posted by jcbyrd  -  01/05/2006 11:01 AM

original wire looked like a screw put thru the firewall had punctured the harness causing a short that eventually burned the wire in two. do not believe it was overloaded but the original wire to coil was small so when I replaced it i used a bigger guage. I was just wondering if wiring the coil through the ignition switch would be better or give higher voltage when starting the car because now I only get about 9.5 volts at the coil when cranking the starter.( the battery is new, in the trunk , with heavy guage cable to starter. car can be hard to start when at operating temperature. starts easy when cold.
jcbyrd [ View ] [ Email ] [ Blogs ] [ Car Ads ] Liberty, Kentucky
 
Posted by jcbyrd  -  01/05/2006 07:13 PM
yes! thatr is exactly what it does. starts as you let go of the ignition switch. what does this mean?
jcbyrd [ View ] [ Email ] [ Blogs ] [ Car Ads ] Liberty, Kentucky
 
Posted by JAWS  -  02/22/2006 07:16 PM

Prior too electronic ignitions and especially with GM until the early 60's, the original ignition switches did not have voltage to both run and start posts at the same time. When the starter solenoid was energized it made contact internally with another post on the opposite side. Providing voltage only then and used as an alternative power source to the coil. As soon as the switch was backed off the run post provided the voltage to the coil. Point style ignitions reqired less votage inorder to prolong point contact life, as 12+ volts burned them up quickly, there was a ballast resistor installed inline from the ignition switch run side only. Contiued cranking with the old system would burn points as well since it was straight battary volts during cranking. Engineers eventually designed the ignition switches to have voltage at the run post as well when in the start position also providing a resistor wire instead of the ballast resistor. Later years the engineers designed and implemented the electronic ignition systems we have now which use 12 volts and have no need of a resistor and one less wire from the starter to the coil.



In your case you will need to have a wire supplying 12 volts to the coil when you are cranking. Either with a ford solenoid or relay of some sort. You could run it Okie style with a switch under the dash....
An electrical headache can make a great car a pain [ View ] [ Email ] [ Blogs ] [ Car Ads ] Boise, Idaho Charter Member since August 2004
 
Posted by Red's Place Custom & Restoration  -  01/05/2006 09:23 PM
if you only have ;one small lead on your starter email me and I will send you a diagram that will show lhow to wire a ford solenoid so it will work right. If you have 2 small leads the one that is for ignition can be run straight to the coil. It will only have voltage during start. hope ;this helps RED
Red's Place Custom & Restoration [ View ] [ Email ] [ Blogs ] [ Car Ads ] Charlotte, North Carolina
 
Posted by Red's Place Custom & Restoration  -  01/05/2006 06:20 PM
your start voltage comes off the ignition side of the starter solenoid. It only puts straight 12 volt to the coil during start . If you have 9 volts going to the coil during start you probably have one of the new high torque starters that doesn't have an ignition side to it. Have you noticed that the motor start just as you let go of the ignition switch.
Red's Place Custom & Restoration [ View ] [ Email ] [ Blogs ] [ Car Ads ] Charlotte, North Carolina
 
Posted by jcbyrd  -  01/05/2006 09:54 PM
only one small lead to starter.will e-mail you.thanks
jcbyrd [ View ] [ Email ] [ Blogs ] [ Car Ads ] Liberty, Kentucky
 
Posted by crash12888  -  01/06/2006 01:21 AM
Could just change the GM solenoid to one with both terminals and add the wire.
crash12888 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Chesterfield, Virginia
 
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