Where does this wire go????
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
Where does this wire go????
1971 350 Auto.
This wi.re is loose and coming out of a wiring bundle on the firewall very close to the coil. The sheath is white and yellow with a red wire inside.
This wi.re is loose and coming out of a wiring bundle on the firewall very close to the coil. The sheath is white and yellow with a red wire inside.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
That wire looks suspiciously like the fusible link that goes to the coil. Try this: with your engine running, measure the voltage at your coil. It should be around 6-8V +/-. Then, have an assistant check the voltage while you are starting it. Your car should get full system voltage during start up and then back to the reduced voltage for running. I don't know what your car should have for its running voltage but that info is in your GM Service Manual. I would have to look mine up but it is around 8 volts.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
That wire looks suspiciously like the fusible link that goes to the coil. Try this: with your engine running, measure the voltage at your coil. It should be around 6-8V +/-. Then, have an assistant check the voltage while you are starting it. Your car should get full system voltage during start up and then back to the reduced voltage for running. I don't know what your car should have for its running voltage but that info is in your GM Service Manual. I would have to look mine up but it is around 8 volts.
I am not able to measure the voltage at the car right now but the car has been hard to start lately. If it is the fusible link, would it attach to the coil positive?
Thanks
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Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
That wire looks suspiciously like the fusible link that goes to the coil. Try this: with your engine running, measure the voltage at your coil. It should be around 6-8V +/-. Then, have an assistant check the voltage while you are starting it. Your car should get full system voltage during start up and then back to the reduced voltage for running. I don't know what your car should have for its running voltage but that info is in your GM Service Manual. I would have to look mine up but it is around 8 volts.
Instructor
Joined: May 2006
Posts: 135
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From: Hot Springs Village AR
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
Yes, there are 3 wires. One +12V from the starter to power the coil during startup, a black one from the ignition to provide lower voltage for running and the 3rd one is a radio static capacitor.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
OK
I took the loose wire in question and hooked it up to the positive side of a voltmeter. I hooked the negative side of the voltmeter to the car frame ground.
With the key off it read 0 volts
with the key on it read 0 volts
with the key to start (cranking) it jumped around from anywhere from 2 to 3 volts
It went bakc to 0 after the car started and the ignition key was in the run position
I repeated the above with the same results except it went higher than 3 volts during the cranking
I then took the voltmeter and hooked it up across the positive and negative terminals of the coil.
It read about 8 volts while the car was running
Does this help any?
Glenn
I took the loose wire in question and hooked it up to the positive side of a voltmeter. I hooked the negative side of the voltmeter to the car frame ground.
With the key off it read 0 volts
with the key on it read 0 volts
with the key to start (cranking) it jumped around from anywhere from 2 to 3 volts
It went bakc to 0 after the car started and the ignition key was in the run position
I repeated the above with the same results except it went higher than 3 volts during the cranking
I then took the voltmeter and hooked it up across the positive and negative terminals of the coil.
It read about 8 volts while the car was running
Does this help any?
Glenn
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
Currently there are only two wires attached to the plus side of the coil. One black wire goes to what looks like a condenser attached to the coil. Another black wire goes into a wiring harness. The wire in question, the red one with the yellow and white sheath, goes into the same wiring harness right next to the black wire. The wire in question was just hanging loose next to the coil. It may have gotten pulled loose while the tach cable was being attatched to the distributor.
Glenn
Glenn
Last edited by gleninsandiego; Feb 11, 2007 at 07:27 PM.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
There should be three wires to the coil, one black on the (-) negative, a yellow and a cermamic woven insulated resistance wire on the (+) positive.
The yellow provides full 12VDC to the coil only when key is in the start position, resistance wire steps voltage down to ~9VDC in the run position to preserve points. Black wire on neg (-) coil post goes to distributer points and breaks voltage to coil triggering the spark.
The yellow provides full 12VDC to the coil only when key is in the start position, resistance wire steps voltage down to ~9VDC in the run position to preserve points. Black wire on neg (-) coil post goes to distributer points and breaks voltage to coil triggering the spark.
Last edited by shafrs3; Feb 11, 2007 at 09:06 PM.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
It sure sounds like that's the wire from the solenoid that supplies 12v for starting. Strange thig is that it only checks 3-4 volts. Can you see if it goes to the starter? If you still have the point type distributor, it should have 2 power wires to it.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
Likes: 0
If that wire has a "dash" coloring code as opposed to a stripped color code convention it is in fact the resistance wire to the coil. Original color was pink with black dashes. Heat from the wire has changed the coloring.
Thread Starter
Safety Car
Joined: Jun 2004
Posts: 4,023
Likes: 1,181
From: La Mesa CA
I appreciate all the help. I still am a bit confused as to the different terms used here, such as a resistance wire.
Given all of the above, should I try hooking it up to the plus side of the coil?
What would be the worst thing that could happen if I do?
Glenn
Given all of the above, should I try hooking it up to the plus side of the coil?
What would be the worst thing that could happen if I do?
Glenn