6 volts at coil - Team Camaro Tech
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post #1 of 10 (permalink) Old Nov 27th, 08, 08:04 PM Thread Starter
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6 volts at coil

I dont know what happened the car was running fine and now it wont start and i have only 6 volts at the coil the the key on.I dont know what the heck the problem is.should I have 12 volts on the wire from the starter with the key on?I dont know why this happened now,could the neutral safety switch cause any of this?
Thanks in advance
Kenny
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post #2 of 10 (permalink) Old Nov 27th, 08, 08:24 PM Thread Starter
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Re: 6 volts at coil

ok I checked the wire coming from the starter to the coil at cranking should I have 12 volts at the coil?Does this mean my solenoid is bad?
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post #3 of 10 (permalink) Old Nov 27th, 08, 08:25 PM
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Re: 6 volts at coil

if this has points, there should be 12 ish volts at the coil when cranking, there will be somewhere like 9 volts with the key on run.
6 volts is low, try adding a jumper wire from + battery to the + side of the coil and see if it will run. Don't leave 12 volts to the coil for a long time, it isn't good for the points.
If it doesn't have points, there is a voltage problem for sure.
Could be the solenoid is bad, I doubt it, check the yellow wire, make sure it is connected to the solenoid, it should be on the S terminal, the one towards the right side of the car.
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post #4 of 10 (permalink) Old Nov 27th, 08, 10:24 PM
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Re: 6 volts at coil

9 volts is nominal voltage for a running motor. But with the points closed and the engine not running, 6 volts may be Ok. Personally its been a long time since I took that measurement, so I'd be tempted to overlook the 6 volt reading for now.

The wire from the firewall connector to the coil is a resistance wire. It serves the same purpose as a ballast resistor. It reduces ignition coil currents when the engine is running to prolong the life of the coil and prevent overheating. As you and Dale stated, the yellow wire from the solenoid will provide 12V while cranking for a hotter spark.

When the engine is running, the voltage on the coil primary will alternate between 12V (when the points are open) and a lower voltage (perhaps 6 volts) when the points are closed. When the engine is running, the voltage on the coil (+) will show a DC reading of Vmin + (Vmax - Vmin) * (1 - Dwell). So if Vmax is 12 volts, Vmin is 6 volts, and the dwell is 30, then the reading on the coil (+) will be 6 + 6*.70 or 10.2 volts... in the ball park of 9 volts.

Long story short, I don't think a 9volt reading on the coil (+) is typical for a non-running motor with the points closed. Perhaps someone with a breaker point setup could measure the coil (+) voltage on a non running motor with the points closed and confirm or correct my statements.

The neutral safety switch only affects engagement of the starter solenoid. If the engine cranks the NSS is ok.

Beware also, that these carberated engines are touchy. If you do in fact have some sort of an igniton problem, you can quickly wind up with a flooded motor which compounds the no start issue.

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Last edited by dnult; Nov 27th, 08 at 10:34 PM.
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post #5 of 10 (permalink) Old Nov 28th, 08, 08:46 AM
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Re: 6 volts at coil

Quote:
Originally Posted by kennys View Post
ok I checked the wire coming from the starter to the coil at cranking should I have 12 volts at the coil?Does this mean my solenoid is bad?
Along with other good suggestions given here, yes, you should have 12 volts, or cranking voltage, on the yellow wire from solenoid to ign coil + terminal.

If you smell raw gas while cranking, hold pedal to the floor while cranking to relieve engine of being flooded.

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post #6 of 10 (permalink) Old Nov 28th, 08, 12:38 PM
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Re: 6 volts at coil

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Originally Posted by kennys View Post
ok I checked the wire coming from the starter to the coil at cranking should I have 12 volts at the coil?Does this mean my solenoid is bad?
I just realized what you meant by this statement. Yes, if the engine cranks but you don't get 12V on your yellow wire, then something is wrong. Either the yellow wire isn't hooked up correctly, has burned through on a header pipe, or the solenoid is bad.

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post #7 of 10 (permalink) Old Nov 28th, 08, 01:59 PM Thread Starter
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Re: 6 volts at coil

ok I jumped 12 volts to coil fired right up does this mean the solenoid is bad? checked continuity on yellow wire no breaks,is my solenoid bad? can that be checked? no 12 coming out of solenoid.
thanks
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post #8 of 10 (permalink) Old Nov 28th, 08, 03:43 PM Thread Starter
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Re: 6 volts at coil

sorry to keep up on this but,I disconnected the yellow wire,with just the wire from the firewall,the car will start,but with the yellow it wont.I meant to tell you that I have a mallory unilite dist. in it.The engine runs better now with no yellow wire than it ever did with,has a more snappy response to the throttle.
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post #9 of 10 (permalink) Old Nov 28th, 08, 07:14 PM
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Re: 6 volts at coil

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Originally Posted by kennys View Post
I meant to tell you that I have a mallory unilite dist. in it.The engine runs better now with no yellow wire than it ever did with, has a more snappy response to the throttle. Kenny
Then don't hook up the yellow wire. Unilite doesn't need it.

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post #10 of 10 (permalink) Old Nov 28th, 08, 07:42 PM Thread Starter
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Re: 6 volts at coil

ok then I was just kinda worried.
thanks for your help
Kenny
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