Still trying to get home

Ken Shaffer

Ken Shaffer

Member
Sep 6, 2017
99
2
8
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
 
I had an extra rebuilt 307 dist at my place. Then with Ken getting some interesting logistics arranged. The dist covered the 300 miles. In about 6 hours. That problem solve.
But now this voltage hoping around. His is a 73. So, there's that resistor wire. 8.4 volts to the BATT terminal. Was the reading I believe. Back in the day. Maybe? I think that the BATT wire goes directly back to the ignition switch. That's mounted on the lower part of the steering column. To me. It seems that this problem. Is coming from that resistor part of the wire. And a dyeing ignition switch.
Bob Dunahugh
 
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
 
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
 
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.

> 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:
>
 
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.

> 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.
>

>
>> 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:
>>
>
 
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/
 
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 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:
>
 
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
 
Ken,

Congratulations on your trip completion!

Please do be sure to let us know anything you learn from this.

Ken H.

> 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:
>
 
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
 
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:
>
 
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