Home » Public Forums » GMCnet » [GMCnet] No spark on #7
| [GMCnet] No spark on #7 [message #210380] |
Sat, 08 June 2013 18:15  |
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Tangerine
Messages: 192
Registered: February 2004
Location: Livonia, MI
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I am about to give up. I have no spark at the distributor cap for #
7. How can that be? I started thinking a bad plug or wire. Changed
them no difference. Than I noticed I have no spark at the distributor
cap. All the others, all 7 of them have spark. but not # 7. I changed
the cap. No difference. I changed the coil, thinking it was weak. No
difference. I still have no spark on #7. This is a Dick Paterson
distributor and wires. All except for # 7. I ruined that wire taking
it off the spark plug. But the problem is in the distributor. There is
no carbon on the underside of the cap and none on the rotor. What am I
missing? I have to get it fixed for next weekend. Have a 400 mile trip
planned.
Please help!
Gary W. Mills (Livonia MI)
. ___________
./_][__][] []| 1974 GMC M/H
.*O-------OO-* Painted Desert
"Tangerine Dream" W/New Frame
./___\.
(o\_!_/o) '74 Love Bug
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1974 GMC 260
Tangerine Dream
Livonia Michigan
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| Re: [GMCnet] No spark on #7 [message #210382 is a reply to message #210380] |
Sat, 08 June 2013 18:30  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Bad cap with a connection problem to #7 point was my first guess, but you changed the cap. How about the rotor? Is it no longer true, perhaps not rotating in a perfect circle? Seems to be the only thing not on your list of changes.
Bummer of a problem.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] No spark on #7 [message #210384 is a reply to message #210380] |
Sat, 08 June 2013 18:33 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Sir: might make sure the cap is seated in the notch, try a different rotor, then back to another cap. I can see it would be a head scratcher.
| Tangerine wrote on Sat, 08 June 2013 19:15 |
I am about to give up. I have no spark at the distributor cap for #
7. How can that be? I started thinking a bad plug or wire. Changed
them no difference. Than I noticed I have no spark at the distributor
cap. All the others, all 7 of them have spark. but not # 7. I changed
the cap. No difference. I changed the coil, thinking it was weak. No
difference. I still have no spark on #7. This is a Dick Paterson
distributor and wires. All except for # 7. I ruined that wire taking
it off the spark plug. But the problem is in the distributor. There is
no carbon on the underside of the cap and none on the rotor. What am I
missing? I have to get it fixed for next weekend. Have a 400 mile trip
planned.
Please help!
Gary W. Mills (Livonia MI)
. ___________
./_][__][] []| 1974 GMC M/H
.*O-------OO-* Painted Desert
"Tangerine Dream" W/New Frame
./___\.
(o\_!_/o) '74 Love Bug
_______________________________________________
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C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] No spark on #7 [message #210387 is a reply to message #210380] |
Sat, 08 June 2013 18:43 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Must be 2 faults causing the diagnostic problem. Cap or wire or plug was out of spec taking out the rest of the chain. Then the replacement wire is bad by chance? How are you testing for spark? Could be fixed now and that plug is just loaded up. Aggressive driving under load may clear it. Can't be the pickup as all the spikes are used at the same time right? Is plug wet??
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] No spark on #7 [message #210398 is a reply to message #210380] |
Sat, 08 June 2013 20:42 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Tangerine wrote on Sat, 08 June 2013 19:15 |
I am about to give up. I have no spark at the distributor cap for # 7. How can that be? I started thinking a bad plug or wire. Changed them no difference. Than I noticed I have no spark at the distributor cap. All the others, all 7 of them have spark. but not # 7.
I changed the cap. No difference.
I changed the coil, thinking it was weak. No difference.
I still have no spark on #7.
This is a Dick Paterson distributor and wires. All except for # 7. I ruined that wire taking it off the spark plug. But the problem is in the distributor. There is no carbon on the underside of the cap and none on the rotor.
What am I missing?
I have to get it fixed for next weekend. Have a 400 mile trip
planned.
Please help!
Gary W. Mills (Livonia MI)
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Gary,
It has to be simple. That does not necessarily make it easy to find.
How are you checking for spark?
It is a '74, but is the distributor HEI?
If it is not, then check for 8 sparks at the coil. I'm not sure you can do this with HEI.
If it is not, but is points, check that point are correct at #7.
If it is Pertronics 1181, check that a magnet hasn't fallen out of the ring.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] No spark on #7 [message #210411 is a reply to message #210398] |
Sat, 08 June 2013 22:22 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Call Dick P in AM.
On Sat, Jun 8, 2013 at 6:42 PM, Matt Colie <matt7323tze@gmail.com> wrote:
>
>
> Tangerine wrote on Sat, 08 June 2013 19:15
> > I am about to give up. I have no spark at the distributor cap for # 7.
> How can that be? I started thinking a bad plug or wire. Changed them no
> difference. Than I noticed I have no spark at the distributor cap. All
> the others, all 7 of them have spark. but not # 7.
> > I changed the cap. No difference.
> > I changed the coil, thinking it was weak. No difference.
> > I still have no spark on #7.
> > This is a Dick Paterson distributor and wires. All except for # 7. I
> ruined that wire taking it off the spark plug. But the problem is in the
> distributor. There is no carbon on the underside of the cap and none on the
> rotor.
> > What am I missing?
> > I have to get it fixed for next weekend. Have a 400 mile trip
> > planned.
> > Please help!
> > Gary W. Mills (Livonia MI)
>
> Gary,
>
> It has to be simple. That does not necessarily make it easy to find.
>
> How are you checking for spark?
>
> It is a '74, but is the distributor HEI?
> If it is not, then check for 8 sparks at the coil. I'm not sure you can
> do this with HEI.
>
> If it is not, but is points, check that point are correct at #7.
> If it is Pertronics 1181, check that a magnet hasn't fallen out of the
> ring.
>
> Matt
>
> --
> Matt & Mary Colie
> '73 Glacier 23 Chaumière (say show-me-air)
> Now with 4 working Rear Brakes
> SE Michigan - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
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--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] No spark on #7 [message #210428 is a reply to message #210380] |
Sun, 09 June 2013 00:20 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I am making an assumption that you are working on a points style ignition with a Pertronix upgrade installed rather than on an HEI distributor.
If you are, then there is a magnetic pick up with a ring spinning next to it with 8 little magnets in it. Those magnets go by the pick up and tell the distributor when to fire. You are probably missing a magnet for number 7, or it for some reason had become DE-magnetized or reverse magnetized. This faulty magnet problem is the cause for failing to trigger the spark on only that one plug.
If you want to know exactly which magnet it is, simply remove the cap and crank the engine until the rotor is pointing to the distributor contact for number 7. Then look for the magnet that is next to the magnetic pickup.
Side note.
I have never worked on a distributor like this one with a Pertronix unit, so my analysis is theory only. I have worked on lots of points type distributors and lot of Pertronix units but never one in an Olds distributor.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] No spark on #7 [message #210449 is a reply to message #210428] |
Sun, 09 June 2013 09:38 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Ken,
Dick Paterson's distributors are OEM HEI with advance curves customized to your coaches weight, final drive, and if you tow or not.
Regards,
Rob M.
-----Original Message-----
From: Ken Burton
I am making an assumption that you are working on a points style ignition with a Pertronix upgrade installed rather than on an HEI
distributor.
If you are, then there is a magnetic pick up with a ring spinning next to it with 8 little magnets in it. Those magnets go by the
pick up and tell the distributor when to fire. You are probably missing a magnet for number 7, or it for some reason had become
DE-magnetized or reverse magnetized. This faulty magnet problem is the cause for failing to trigger the spark on only that one
plug.
If you want to know exactly which magnet it is, simply remove the cap and crank the engine until the rotor is pointing to the
distributor contact for number 7. Then look for the magnet that is next to the magnetic pickup.
Side note.
I have never worked on a distributor like this one with a Pertronix unit, so my analysis is theory only. I have worked on lots of
points type distributors and lot of Pertronix units but never one in an Olds distributor.
Ken B.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] No spark on #7 [message #210467 is a reply to message #210380] |
Sun, 09 June 2013 13:08 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Gary -
Have a look at the points cam. Any chance you have a low or worn off #7 lobe such that the points don't open? Or if it's a pointless, look for a missing or short lobe on the tone wheel.
--johnny
From: Gary Mills <daveel@ix.netcom.com>
To: Gmclist <gmclist@temp.gmcnet.org>
Sent: Saturday, June 8, 2013 7:15 PM
Subject: [GMCnet] No spark on #7
I am about to give up. I have no spark at the distributor cap for #
7. How can that be? I started thinking a bad plug or wire. Changed
them no difference. Than I noticed I have no spark at the distributor
cap. All the others, all 7 of them have spark. but not # 7. I changed
the cap. No difference. I changed the coil, thinking it was weak. No
difference. I still have no spark on #7. This is a Dick Paterson
distributor and wires. All except for # 7. I ruined that wire taking
it off the spark plug. But the problem is in the distributor. There is
no carbon on the underside of the cap and none on the rotor. What am I
missing? I have to get it fixed for next weekend. Have a 400 mile trip
planned.
Please help!
Gary W. Mills (Livonia MI)
. ___________
./_][__][] []| 1974 GMC M/H
.*O-------OO-* Painted Desert
"Tangerine Dream" W/New Frame
./___\.
(o\_!_/o) '74 Love Bug
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] No spark on #7 [message #210469 is a reply to message #210449] |
Sun, 09 June 2013 13:25 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I believe Dick also offers a points distributor with the points removed and a Pertronix type device in it. He then tunes this like he does for the GMC coach. This distributor fits Pre-HEI (1973 to 1975) coaches.
I'll try to remember to telephone him tomorrow and verify that my statement is correct.
Ken
| Robert Mueller wrote on Sun, 09 June 2013 09:38 |
Ken,
Dick Paterson's distributors are OEM HEI with advance curves customized to your coaches weight, final drive, and if you tow or not.
Regards,
Rob M.
-----Original Message-----
From: Ken Burton
I am making an assumption that you are working on a points style ignition with a Pertronix upgrade installed rather than on an HEI
distributor.
If you are, then there is a magnetic pick up with a ring spinning next to it with 8 little magnets in it. Those magnets go by the
pick up and tell the distributor when to fire. You are probably missing a magnet for number 7, or it for some reason had become
DE-magnetized or reverse magnetized. This faulty magnet problem is the cause for failing to trigger the spark on only that one
plug.
If you want to know exactly which magnet it is, simply remove the cap and crank the engine until the rotor is pointing to the
distributor contact for number 7. Then look for the magnet that is next to the magnetic pickup.
Side note.
I have never worked on a distributor like this one with a Pertronix unit, so my analysis is theory only. I have worked on lots of
points type distributors and lot of Pertronix units but never one in an Olds distributor.
Ken B.
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Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] No spark on #7 [message #210476 is a reply to message #210469] |
Sun, 09 June 2013 16:12 |
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Ken, you are correct; I have one Dick's distributors on my '73. It does not use magnets, however, it has a lobe sensing device and the cap is marked "MSD" on it. I don't see how that could be a problem, so maybe a call to Dick is in order. I'd try one of the other plug wires in #7 to see if it fires OK.
geo groth '73 260 Sequoia
Carson City Nevada 89703
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| Re: [GMCnet] No spark on #7 [message #210485 is a reply to message #210476] |
Sun, 09 June 2013 16:34 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| ggroth wrote on Sun, 09 June 2013 16:12 |
Ken, you are correct; I have one Dick's distributors on my '73. It does not use magnets, however, it has a lobe sensing device and the cap is marked "MSD" on it. I don't see how that could be a problem, so maybe a call to Dick is in order. I'd try one of the other plug wires in #7 to see if it fires OK.
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I thought he already tried swapping wires.
My thought is if there is no spark is being generated on position 7 only, then there is something wrong with the pick up sensing in position 7. If it is a lobe sensing rather than a magnet sensing, then there has to be something preventing that pick up from sensing when the lobe for 7 comes by. Having never seen the actual MSD pick up I can only guess at this point. Is there an adjustment or clearance that has to be set for that pickup? Is the pickup sensing the high spots on where the points use to run? May be one of the high spots is worn down.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] No spark on #7 [message #210488 is a reply to message #210485] |
Sun, 09 June 2013 16:39 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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If he was close by I would throw an oscilloscope on it and see what is happening. If there is no fire in position 7 then we would know it is a sensing problem. If there is low voltage on 7 we would know there is a short to ground somewhere. If there is a high voltage spike we would know that the rotor, cap, spark plug wire, or plug is open.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] No spark on #7 [message #210576 is a reply to message #210496] |
Mon, 10 June 2013 10:53 |
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Tangerine
Messages: 192
Registered: February 2004
Location: Livonia, MI
Karma: 0
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Senior Member |
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On 6/9/2013 6:11 PM, Brian Waddell wrote:
> if you have a ignition modulator sp? try changing it ...worked for me on my dick p.....set up
>
>
>> To: gmclist@temp.gmcnet.org
>> From: n9cv@comcast.net
>> Date: Sun, 9 Jun 2013 16:39:47 -0500
>> Subject: Re: [GMCnet] No spark on #7
>>
>>
>>
>> If he was close by I would throw an oscilloscope on it and see what is happening. If there is no fire in position 7 then we would know it is a sensing problem. If there is low voltage on 7 we would know there is a short to ground somewhere. If there is a high voltage spike we would know that the rotor, cap, spark plug wire, or plug is open.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
Well It's hitting on all 8 once again. It turns out that you are all
right, some more than others. I called Dick Paterson yesterday. He
said that he has only had a few cases where the magnet fell out of the
magnet ring. He said that is why they do not use this system on the
marine engines. Hitting the wave would knock the magnets out. The
magnet had to be stuck to a piece of iron within the distributor, under
the cap. He was right and with the help of a dental mirror I found
where it fell from. I glued it in with Gorilla Glue. Along with
another loose one.
So lessen learned. I know where to look, if it should happen again.
But I hope not.
Gary W. Mills (Livonia MI)
. ___________
./_][__][] []| 1974 GMC M/H
.*O-------OO-* Painted Desert
"Tangerine Dream" W/New Frame
./___\.
(o\_!_/o) '74 Love Bug
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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1974 GMC 260
Tangerine Dream
Livonia Michigan
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| Re: [GMCnet] No spark on #7 [message #210607 is a reply to message #210588] |
Mon, 10 June 2013 17:29 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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It does not matter who is right or who is wrong (unless it is Rob driving his GMC down the wrong side of the highway). What matters is he found the problem and we all learned something.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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