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Old 06-08-2014, 09:23 PM   #1
Orange72ChevyC10
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Ignition Problem

Ok, so I am getting 12v at the positive post of the coil (points style ignition)my wiring harness on the driver side firewall appears not to have a resistor wire (pic attached)...so I install a BWD RU19 resistor between the yellow wire and + term of the coil and I'm still reading 12v (at the wire separate and connected to coil) with the ignition on.

Am I crazy or should I see less than 12v with the ballast resistor installed?

http://www.oreillyauto.com/site/c/de...2763&ppt=C0334
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Old 06-08-2014, 09:48 PM   #2
geezer#99
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Re: Ignition Problem

Take the wire insulation off the wire from the coil + back towards the firewall and if you find a section with a cloth cover on the wire, that's the resistor section. It should be a silver single strand wire.
The yellow wire from the starter supplies 12v to the coil only while starting. The resistor wire supplies 7-8 volts when running.
Is the yellow wire hooked to the starter correctly. To the 'S' terminal. The one closest to the engine block.
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Old 06-08-2014, 09:58 PM   #3
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Re: Ignition Problem

Point ignition works like this: there should be 1 wire from the ignition switch that either is a resister wire or has a resister in it. There is a second wire from the starter solenoid to the coil that provides a full 12v when the engine is cranking for easier starting. Almost everything I have with points has been converted to electronic with the accell or pertonics with the exception of 2 old Briggs cast iron 16 hp which I wired that way.
Points last a lot longer running on 8-9v but will work on 12v for about a yr or so of normal driving. I use the Chrysler ballast resistor and it works great for this. It's not GM correct but dirt cheap and highly effective as a test device. Make sure you only have 1 wire to the positive side of the coil for testing, the last of the point engines had an electronic box that maintained 12v whenever the key was on but engine off. The best test is voltage test key on engine off then start it and check voltage at idle. If they read the same something is wired wrong or bad electronic box.
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Old 06-09-2014, 01:28 AM   #4
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Re: Ignition Problem

Thanks for the responses so far, I should say the truck does not run, the reason I am checking voltage is I have no spark.

Geezer...the yellow wire from the + of the coil is connected to the "R" post on the starter solenoid. Everything I researched seemed to have the Purple to the "S". If this isn't the case that's where I will start first.

I will confirm tomorrow if there is a resistor between the coil and stater on the yellow line.
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Old 06-09-2014, 08:54 AM   #5
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Re: Ignition Problem

Apoligies!!
You're right. 'S' is for purple. 'R' is for yellow. The 'R' is sometimes an 'I' on some solenoids.
No spark can be caused by bad points too.
If you unwrap the wires you'll find where the wire from the coil, the resistor wire and the yellow wire are connected togethor.
Oh ya' Welcome to the forum!!
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Old 06-09-2014, 08:59 AM   #6
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Re: Ignition Problem

Thanks again, going to look for the resistor wire this afternoon.

I have a new set of points not installed yet, I just don't want to keep sending 12v to them incase it's frying the condenser.
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Old 06-09-2014, 07:18 PM   #7
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Re: Ignition Problem

Ok so I have removed the entire wire bundle and unbolted it completely from the starter and firewall (ends).

The Pink wire is split into two yellow wires (starter solenoid and coil+) however there is to resistor wire anywhere. Thoughts?
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Old 06-09-2014, 07:19 PM   #8
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Re: Ignition Problem

Another pic...
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Old 06-09-2014, 07:23 PM   #9
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Re: Ignition Problem

Last one.
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Old 06-09-2014, 08:15 PM   #10
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Re: Ignition Problem

GM was notorious for building the resistor into the wire. To find it connect your ohms meter and if it's not infinite that's your resistor. If all read infinite it's time to add a resistor
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Old 06-09-2014, 11:27 PM   #11
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Re: Ignition Problem

Thanks Rick will check tomorrow.
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Old 06-10-2014, 08:00 AM   #12
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Re: Ignition Problem

Pink wire tested out at 1.4 Ohms. I am clueless if this is good or not.
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Old 06-10-2014, 08:49 AM   #13
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Re: Ignition Problem

See how many volts you get thru it. One end on the positive, other end hooked to your volt meter which is grounded to your negative post.
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Old 06-10-2014, 06:06 PM   #14
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Re: Ignition Problem

The connection point of the pink and yellow wires as well as the ends of each yellow wire show 12.6v...

????????
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Old 06-10-2014, 06:39 PM   #15
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Re: Ignition Problem

That means no resistor wire.
That connection of the 2 yellows and pink looks suspect. I pulled the one apart on my 67 and the three were soldered together. Maybe someone put an hei in before you got it and changed it back to a points dizzy without a wire change.
You could keep the points and splice in a mopar style ballast resistor on the pink wire or swap to an hei.
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Old 06-11-2014, 01:30 AM   #16
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Re: Ignition Problem

I believe HEI is the likely next step all though I want to understand the points system better.

Thanks all for the help.

Jason
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