? About yellow wire to starter - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OhioDan · 03-17-2005, 03:51 AM

I installed a new wire harness for the engine, modified for HEI ign. There's a yellow wire that terminates at the starter. I know on a point ign., this would go to the dist., and on HEI ign., this is to be disconnected and taped off. What I was wondering, could I connect it, and somewhere behind the engine, use it as 12V to my electric choke. I mean it's key hot right? Why couldn't I connect it at the starter, and terminate it at the electric choke? I could install an inline fuse to CMA against burning it up. Any ideas? Any help would be appreciated. Thanx

GMC AMI · 03-17-2005, 04:18 AM

The yellow wire that goes to the r post on the starter is a resistor wire and it will not run 12 volts. It would be closer to 9v. Use another wire.

**'68OrangeSunshine** · 03-17-2005, 04:58 AM

Mike's right. It has 12 vdc initially, but as it heats up resistance increases and voltage drops to 7 vdc. It was originally designed to keep the points from burning up.

OhioDan · 03-17-2005, 05:50 AM

MMMM, now I gotta break out my wiring diagram and trouble light again. Any ideas on which wire I could use? Or will I hafta run another wire?

**'68OrangeSunshine** · 03-17-2005, 06:03 AM

Just run a new line from an empty Ign On tap in the fuse block, thru the firewall and out to your choke. That way you know it's not draining volts from some other service. Doesn't have to be a large diameter wire. 18 - 22 ga. should be fine, chokes don't draw a lot of current. A different color from the other lines in that end of the harness will help troubleshooting later. You can bundle the new line with zip ties or Eastwood sells OEM type non-stick vinyl black tape if you want the original look.

Longhorn Man · 03-17-2005, 07:01 AM

That isn't a resistance wire, It does carry 12 volts, He's asking about the yellow wire that would take 12 volts from the starter while cranking the engine and send the full increased voltage to the coil fort easier starts.
However, it still wouldn't work becouse that wire is only hot when you are twisting the key.

GMC AMI · 03-17-2005, 09:11 AM

My 71 GMC has a yellow resister wire. That threw me off. I am BAD so slap me Andy.

I have also seen white braided alum.
The resistor wire does run off the ign. switch only on the run position.
I was wrong and Andy is right.

Still what I said about using a diff. wire still holds true for the choke wire.

Longhorn Man · 03-17-2005, 05:26 PM

That's right...same answer, different reason.

Sweet72 · 03-17-2005, 06:24 PM

Quote:

Originally Posted by '68OrangeSunshine

Mike's right. It has 12 vdc initially, but as it heats up resistance increases and voltage drops to 7 vdc. It was originally designed to keep the points from burning up.

At the risk of sounding like a smart ass... I have to correct your statement about how the resistor wire comes into play.
With the key in the "start" position the starter solenoid contacts close providing a full 12 volts to the + terminal of your ign. coil via that yellow wire, and after the key is released to the "on" position those contacts open and now the resistor wire (which by the way drops voltage to approx. 8 volts) is providing power to the + terminal of the coil thus prolonging the life of the point contacts.

**VetteVet** · 03-18-2005, 01:11 AM

If the harness is modified then why does it still have the yellow wire in it and where does the other end terminate. In the original harness this wire went directly to the coil from the solenoid and fed it full 12 volts as has been said and a brown wire from the key switch run position also went to the coil and was the resistance wire as has also been said.So what's my point?
I agree with 68orange that you should run a completely separate wire to feed the coil and make sure it is fused and key on hot only or you will have a battery drain problem.
VetteVet-- is there an echo in here? LOL

Longhorn Man · 03-18-2005, 01:30 AM

ECHO ECHO ECHO ECHO ECHO ;

The new wire needs to be hot in both crank and in run...if it is an acc location, it'll be turned off when you crank the engine, which makes starting interesting at the least.
IMO, a 25 amp fuse is good. If you wind the motor real hard, it needs all the amps it can get. I honestly run a 30 amp on mine. It'll still blow out if it gets shorted out.

**VetteVet** · 03-18-2005, 02:03 AM

Andy I meant to say choke coil not hei coil. I'm trying to figure how he's going to feed the choke coil off the key switch without grounding the hei feed wire off the hot key on position. Your're right the start and run both have to be hot to the hei coil.
My Haynes shows the later model schematics run the choke coil in the start or run key switch position so I figure the choke coil must have enough resistance to not ground the ignition coil out.
VetteVet

**'68OrangeSunshine** · 03-18-2005, 05:17 AM

Quote:

Originally Posted by '68OrangeSunshine

Mike's right. It has 12 vdc initially, but as it heats up resistance increases and voltage drops to 7 vdc. It was originally designed to keep the points from burning up.

Well, that's what it read on my $10 pocket VOM. I always stand correctible on electric matters. On my '68 L6, There is a splice in the harness behind the bellhousing . Power comes down the one-strand iconel wire in a white -braided jacket [dare I say asbestos?] from the firewall bulkhead connector and splices into a yellow 16-18 ga line that goes to the starter on one end and the Coil on the other. It's been that way since I bought it, or is it not standard? And Maybe,

... after a good time on St Paddy's nite, I can't recollect for certain ALL the little avenues in the engine harness circuit, no matter how long I'd had that rig?

Putter · 03-18-2005, 11:00 AM

Mine has the same setup. White 'braided' wire to a splice that turns into a pair of yellow wires.
MY QUESTION: Can I leave one of those yellows on the starter (like it originally was), and use the other yellow to trigger a relay that will allow FULL BATTERY 12+ volts to flow to the HEI? Even if that yellow wire drops to 7 or 8 volts, that will still trigger my relay, right? I have no problem yanking the white wire out and replacing it with a new "pink" wire, but why wouldn't the realy idea work??
ANYONE?
INPUT?

**VetteVet** · 03-18-2005, 02:09 PM

Hey guys I just found this site on google for a 74 nova that shows a schematic and besides it gives a lot of info on HEI stuff. Take a look.

http://rmcavoy.freeshell.org/HEI.html

VV

Longhorn Man · 03-18-2005, 07:50 PM

Putter, yes, that would work.

03-17-2005, 03:51 AM	#1
OhioDan Registered User Join Date: Apr 2002 Location: New Carlisle, Ohio,USA Posts: 1,404	? About yellow wire to starter I installed a new wire harness for the engine, modified for HEI ign. There's a yellow wire that terminates at the starter. I know on a point ign., this would go to the dist., and on HEI ign., this is to be disconnected and taped off. What I was wondering, could I connect it, and somewhere behind the engine, use it as 12V to my electric choke. I mean it's key hot right? Why couldn't I connect it at the starter, and terminate it at the electric choke? I could install an inline fuse to CMA against burning it up. Any ideas? Any help would be appreciated. Thanx __________________ LIFE AIN'T EASY WHEN YER FAT AND GREASY! GMC= Got More Class! 1970 GMC LWB, Fleetside, 350/4spd, Flowmaster "40's", 2002 GMC 16" Rallies, cowl hood,and added a bunch of options that weren't there when I started.

03-17-2005, 04:18 AM	#2
GMC AMI Registered User Join Date: Apr 2004 Location: The Other Maine! Posts: 2,236	The yellow wire that goes to the r post on the starter is a resistor wire and it will not run 12 volts. It would be closer to 9v. Use another wire. __________________ 1968 Chevy 4x4 307 4 speed

03-17-2005, 04:58 AM	#3
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,517	Mike's right. It has 12 vdc initially, but as it heats up resistance increases and voltage drops to 7 vdc. It was originally designed to keep the points from burning up. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

03-17-2005, 05:50 AM	#4
OhioDan Registered User Join Date: Apr 2002 Location: New Carlisle, Ohio,USA Posts: 1,404	MMMM, now I gotta break out my wiring diagram and trouble light again. Any ideas on which wire I could use? Or will I hafta run another wire? __________________ LIFE AIN'T EASY WHEN YER FAT AND GREASY! GMC= Got More Class! 1970 GMC LWB, Fleetside, 350/4spd, Flowmaster "40's", 2002 GMC 16" Rallies, cowl hood,and added a bunch of options that weren't there when I started.

03-17-2005, 06:03 AM	#5
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,517	Just run a new line from an empty Ign On tap in the fuse block, thru the firewall and out to your choke. That way you know it's not draining volts from some other service. Doesn't have to be a large diameter wire. 18 - 22 ga. should be fine, chokes don't draw a lot of current. A different color from the other lines in that end of the harness will help troubleshooting later. You can bundle the new line with zip ties or Eastwood sells OEM type non-stick vinyl black tape if you want the original look. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

03-17-2005, 07:01 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	That isn't a resistance wire, It does carry 12 volts, He's asking about the yellow wire that would take 12 volts from the starter while cranking the engine and send the full increased voltage to the coil fort easier starts. However, it still wouldn't work becouse that wire is only hot when you are twisting the key.

03-17-2005, 09:11 AM	#7
GMC AMI Registered User Join Date: Apr 2004 Location: The Other Maine! Posts: 2,236	My mistake. My 71 GMC has a yellow resister wire. That threw me off. I am BAD so slap me Andy. I have also seen white braided alum. The resistor wire does run off the ign. switch only on the run position. I was wrong and Andy is right. Still what I said about using a diff. wire still holds true for the choke wire. __________________ 1968 Chevy 4x4 307 4 speed

03-17-2005, 05:26 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	That's right...same answer, different reason.

03-18-2005, 01:11 AM	#10
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	to choke or not to choke If the harness is modified then why does it still have the yellow wire in it and where does the other end terminate. In the original harness this wire went directly to the coil from the solenoid and fed it full 12 volts as has been said and a brown wire from the key switch run position also went to the coil and was the resistance wire as has also been said.So what's my point? I agree with 68orange that you should run a completely separate wire to feed the coil and make sure it is fused and key on hot only or you will have a battery drain problem. VetteVet-- is there an echo in here? LOL __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

03-18-2005, 01:30 AM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	ECHO ECHO ECHO ECHO ECHO ; The new wire needs to be hot in both crank and in run...if it is an acc location, it'll be turned off when you crank the engine, which makes starting interesting at the least. IMO, a 25 amp fuse is good. If you wind the motor real hard, it needs all the amps it can get. I honestly run a 30 amp on mine. It'll still blow out if it gets shorted out.

03-18-2005, 02:03 AM	#12
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Andy I meant to say choke coil not hei coil. I'm trying to figure how he's going to feed the choke coil off the key switch without grounding the hei feed wire off the hot key on position. Your're right the start and run both have to be hot to the hei coil. My Haynes shows the later model schematics run the choke coil in the start or run key switch position so I figure the choke coil must have enough resistance to not ground the ignition coil out. VetteVet __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

03-18-2005, 11:00 AM	#14
Putter More Cowbell.... Join Date: Mar 2004 Location: Puckett, MS Posts: 3,569	Mine has the same setup. White 'braided' wire to a splice that turns into a pair of yellow wires. MY QUESTION: Can I leave one of those yellows on the starter (like it originally was), and use the other yellow to trigger a relay that will allow FULL BATTERY 12+ volts to flow to the HEI? Even if that yellow wire drops to 7 or 8 volts, that will still trigger my relay, right? I have no problem yanking the white wire out and replacing it with a new "pink" wire, but why wouldn't the realy idea work?? ANYONE? INPUT? __________________ *There once was a member from Puckett.....Who ( fill in the blank blank blank* ) bucket**

03-18-2005, 02:09 PM	#15
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,719	Ignition diagram Hey guys I just found this site on google for a 74 nova that shows a schematic and besides it gives a lot of info on HEI stuff. Take a look. http://rmcavoy.freeshell.org/HEI.html VV __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

03-18-2005, 07:50 PM	#16
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Putter, yes, that would work.



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