Home » Public Forums » GMCnet » Still trying to get home (I don’t have 12v to distributor batt terminal )
| Still trying to get home [message #366566] |
Tue, 07 September 2021 23:36  |
Ken Shaffer
Messages: 89
Registered: September 2017
Location: Marion Iowa
Karma: -1
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I put on a new distributor and still no spark. I measured power to distributor and voltage is bouncing all over. Can’t get a true reading. I hot wired from battery directly to distributor and it fired right up. What can cause that 12v source to go haywire?
I am off interstate and safe into a truck stop
Ken Shaffer
Marion Iowa
73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
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| Re: Still trying to get home [message #366569 is a reply to message #366566] |
Wed, 08 September 2021 02:05  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I am not sure what you guys are doing there but if this is a traditional non-hei distributor then 8 volts while running and 12 volts, or a little less while cranking, is about normal. While running the power to the coil is supplied through a pink resistance wire. While cranking power is supplied to the coil through a yellow wire running from one small terminal on the starter solenoid direct to the coil. Your Observation that is runs when +12 volts is supplied direct to the coil tells me that your issue is power supply to the coil. I would tell you to just jumper +12 volts to the coil could and go EXCEPT the resistor is there for a reason. It is there to limit the amount of current across the points. Without the resistor you will quickly burn the contact surfaces of the points.
Now here comes my confusion. I have read in previous postings in this thread about EFI and computer control of the distributor. So you may have modified the wiring from OEM and I have no idea what was done. If it was mine I would install a temporary wire to +12 volts (probably batter positive) with an inline ignition resistor and drive it home. Get any GM ignition resistor and wire it in series with that +12 jumper installed and drive away. If you can not find a GM resistor, Go to an electronics store and get a 1.5 ohm 10 watt resistor. The GMC wiring diagram says that the OEM value is 1.35 ohms.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Still trying to get home [message #366570 is a reply to message #366566] |
Wed, 08 September 2021 02:25 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Well, I typed all of that answer and now discover there are two threads. So a lot of what I said probably doesn't apply. Does the 307 the distriubutor used have a separate coil or is it like an HEI one? It still sound like a voltage supply problem or aground to the engine. You might add a jumper wire from the base of the distributor and an engine bolt.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| [GMCnet] Re: Still trying to get home [message #366571 is a reply to message #366566] |
Wed, 08 September 2021 05:57 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Ken,
I'd forgotten my earlier discussion with Bob D. about your ignition
wiring. I presume you at that time eliminated the resistance wire between
the power source and the distributor/ignition coil. That MUST be replaced
when installing HEI, as you did with EFI.
I don't agree with installing a relay, controlled through the resistance
wire, to provide full voltage to the distributor -- unnecessary
complication/potential problem source. Make your temporary fix permanent
by connecting the source end to an IGN buss source.
JWID,
Ken H.
On Wed, Sep 8, 2021 at 12:37 AM Ken Shaffer wrote:
> I put on a new distributor and still no spark. I measured power to
> distributor and voltage is bouncing all over. Can’t get a true reading. I
> hot
> wired from battery directly to distributor and it fired right up. What
> can cause that 12v source to go haywire?
>
> I am off interstate and safe into a truck stop
> --
> Ken Shaffer
> Marion Iowa
> 73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi
> hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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GMCnet mailing list
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| [GMCnet] Re: Still trying to get home [message #366573 is a reply to message #366571] |
Wed, 08 September 2021 06:09 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Ken,
Another thought -- about your tight distributor shafts: While Jim H.'s
comments about the oil feed hole at the rear of the block are valid, there
may be another explanation for your repeated "freeze-ups": The distributor
shaft has a spiral groove around it which is intended to carry oil up into
the bushing in the distributor body. If that is completely filled with
residual carbon from years of use, it may not provide adequate lubrication
to the shaft, allowing galling and difficult rotation. Be SURE that groove
is clear every time you have the distributor out.
Ken H.
On Wed, Sep 8, 2021 at 6:57 AM Ken Henderson wrote:
> Ken,
>
> I'd forgotten my earlier discussion with Bob D. about your ignition
> wiring. I presume you at that time eliminated the resistance wire between
> the power source and the distributor/ignition coil. That MUST be replaced
> when installing HEI, as you did with EFI.
> I don't agree with installing a relay, controlled through the resistance
> wire, to provide full voltage to the distributor -- unnecessary
> complication/potential problem source. Make your temporary fix permanent
> by connecting the source end to an IGN buss source.
>
> JWID,
>
> Ken H.
>
> On Wed, Sep 8, 2021 at 12:37 AM Ken Shaffer wrote:
>
>> I put on a new distributor and still no spark. I measured power to
>> distributor and voltage is bouncing all over. Can’t get a true reading. I
>> hot
>> wired from battery directly to distributor and it fired right up. What
>> can cause that 12v source to go haywire?
>>
>> I am off interstate and safe into a truck stop
>> --
>> Ken Shaffer
>> Marion Iowa
>> 73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi
>> hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
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GMCnet mailing list
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Still trying to get home [message #366574 is a reply to message #366566] |
Wed, 08 September 2021 06:46 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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on a 78..... that wire to the distributor goes across inside of dash wiring harness, exits the firewall through the fuseblock and goes down the wire loom to engine. that connection in fuse block may or may not be a problem.... It is not fused there, just connects and passes through. that is how I remember a 78 I had to fix that shorted out that wire on the block and melted it back.
little confused- if you switched to the HEI, the resistor should be removed, so you always have full voltage to the HEI. Grounding is important as well.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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| [GMCnet] Re: Still trying to get home [message #366575 is a reply to message #366574] |
Wed, 08 September 2021 07:37 |
Ken Shaffer
Messages: 89
Registered: September 2017
Location: Marion Iowa
Karma: -1
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Member |
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While typing up a long winded explanation of where are my 12 V power source
comes from on my affordable EFI harness, I found the blown fuse! Problem
solved. I didn’t remember that wire going to my added fuse block…
Wiring problem solved. Now hopefully my néw distributor will get me home.
I have good end play with a couple paper shims added. Wish me luck and
thank you ALL!
Ken
On Wed, Sep 8, 2021 at 6:46 AM Jon Roche wrote:
> on a 78..... that wire to the distributor goes across inside of dash
> wiring harness, exits the firewall through the fuseblock and goes down the
> wire loom to engine. that connection in fuse block may or may not be a
> problem.... It is not fused there, just connects and passes through.
> that is how I remember a 78 I had to fix that shorted out that wire on the
> block and melted it back.
>
>
>
> little confused- if you switched to the HEI, the resistor should be
> removed, so you always have full voltage to the HEI. Grounding is
> important as
> well.
>
>
>
>
> --
> Jon Roche
> 75 palm beach
> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Shaffer
Marion Iowa
73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
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| Re: Still trying to get home [message #366605 is a reply to message #366566] |
Wed, 08 September 2021 18:47 |
Ken Shaffer
Messages: 89
Registered: September 2017
Location: Marion Iowa
Karma: -1
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Member |
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Home safe and sound!
Thanks to all. I will be taking apart the old distributors and trying to find out what really happened. If I ever figure it out, I will post a reply. In the meantime, I will be putting a temperature sensor on the shaft of my distributor. Paranoid? Maybe
Ken Shaffer
Marion Iowa
73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
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| [GMCnet] Re: Still trying to get home [message #366606 is a reply to message #366605] |
Wed, 08 September 2021 18:51 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Ken,
Congratulations on your trip completion!
Please do be sure to let us know anything you learn from this.
Ken H.
On Wed, Sep 8, 2021 at 7:47 PM Ken Shaffer wrote:
> Home safe and sound!
> Thanks to all. I will be taking apart the old distributors and trying to
> find out what really happened. If I ever figure it out, I will post a
> reply. In the meantime, I will be putting a temperature sensor on the
> shaft of my distributor. Paranoid? Maybe
> --
> Ken Shaffer
> Marion Iowa
> 73 Canyon Lands, 455, Micro-level, Alum radiator, Alcoa wheels, Lenzi
> hubs/bearings, Howell EFI/EBL, Rostra Cruise, Custom interior
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Still trying to get home [message #366610 is a reply to message #366566] |
Wed, 08 September 2021 20:21 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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On distributors— All makes, after cleaning off the stiction from shafts (shaft within a shaft) i coat the entire thing with Valvoline full synthetic grease prior to reassembly. The idea that oil will go up hill to the top bearing might have worked on paper but stiction thwarts that. Once this is done I have not had reoccurring problems with bind or squeal
John Lebetski
Woodstock, IL
77 Eleganza II
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| [GMCnet] Re: Still trying to get home [message #366655 is a reply to message #366610] |
Thu, 09 September 2021 19:55 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Senior Member |
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Appears to me that Hupy might be ontoit
Sully
Bellevue wa
On Wed, Sep 8, 2021 at 6:21 PM John R. Lebetski
wrote:
> On distributors— All makes, after cleaning off the stiction from shafts
> (shaft within a shaft) i coat the entire thing with Valvoline full synthetic
> grease prior to reassembly. The idea that oil will go up hill to the top
> bearing might have worked on paper but stiction thwarts that. Once this is
> done I have not had reoccurring problems with bind or squeal
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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