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| [GMCnet] Start problem [message #64508] |
Mon, 16 November 2009 14:33  |
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Dennis[1]
Messages: 4
Registered: April 2009
Karma: 0
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Junior Member |
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I have a start problem and need some help understanding what is happening.
The vehicle is a 1973 23 foot GMC motorhome, that has been retrofitted with HEI.
The transmission was out to replace the flex-plate, which had cracked. The flex plate is now fixed.
The transmission mechanic said that they had trouble getting it to start, and had to tap on the starter solenoid to get it to start, and that I may need to replace the starter soon. This is a new problem that I have not experienced before.
It started OK at the transmission shop after the flex plate work was done.... and drove home fine.
But then, as predicted by the transmission mechanic, the starter would not start the motorhome. Tapping on the starter did not help.
After replacing the starter with a re-built unit the vehicle starts when the key is in "start" position, but as soon as the key is returned to "run" the engine quits.
When replacing the starter, the Yellow wire was returned to the R (resistor wire) terminal, which I understand is not used on HEI, but it was connected to the old starter.
The purple wire was returned to the "S" (start) terminal. Connections are good.
Is there an easy way to diagnose and solve this problem?
Thanks in advance.
Dennis Schosboek
Port Angeles, WA
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| Re: [GMCnet] Start problem [message #64510 is a reply to message #64508] |
Mon, 16 November 2009 14:52  |
 |
wally
Messages: 643
Registered: August 2004
Location: Omaha Nebraska
Karma: 5
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Senior Member |
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| Dennis[1 |
wrote on Mon, 16 November 2009 14:33]I have a start problem and need some help understanding what is happening.
The vehicle is a 1973 23 foot GMC motorhome, that has been retrofitted with HEI.
The transmission was out to replace the flex-plate, which had cracked. The flex plate is now fixed.
The transmission mechanic said that they had trouble getting it to start, and had to tap on the starter solenoid to get it to start, and that I may need to replace the starter soon. This is a new problem that I have not experienced before.
It started OK at the transmission shop after the flex plate work was done.... and drove home fine.
But then, as predicted by the transmission mechanic, the starter would not start the motorhome. Tapping on the starter did not help.
After replacing the starter with a re-built unit the vehicle starts when the key is in "start" position, but as soon as the key is returned to "run" the engine quits.
When replacing the starter, the Yellow wire was returned to the R (resistor wire) terminal, which I understand is not used on HEI, but it was connected to the old starter.
The purple wire was returned to the "S" (start) terminal. Connections are good.
Is there an easy way to diagnose and solve this problem?
Thanks in advance.
Dennis Schosboek
Port Angeles, WA
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A quick check would be to see if you have 12 volts at the HEI when the ignition switch is in the run position. Beings it has been converted to HEI the resistor wire should have been bypassed or changed.
HTH
Wally Anderson
Omaha NE
75 Glenbrook
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| Re: [GMCnet] Start problem [message #64533 is a reply to message #64508] |
Mon, 16 November 2009 16:37 |
Rick Denney
Messages: 430
Registered: January 2004
Karma: 0
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Senior Member |
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Dennis writes...
> When replacing the starter, the Yellow wire was returned to the R
> (resistor wire) terminal, which I understand is not used on HEI, but
> it was connected to the old starter.
> The purple wire was returned to the "S" (start) terminal. Connections are good.
> Is there an easy way to diagnose and solve this problem?
Run a big heavy wire from the engine block to the chassis. The
mechanic probably forgot to replace the ground strap to the engine,
which is usually mounted to the transmission.
These sorts of problems are almost always ground problems. The current
has to make it all the way from the positive terminal on the battery
back to the negative terminal on the battery.
I found an unused bolt in the side of the block that I made into a new
central grounding point for the chassis electrical system. The engine
battery negative terminal goes there, and then I run a strap from
there to the frame. I also have a strap from that frame connection to
the aluminum body structure, which is the official spot where the body
(which serves as the ground for the house 12-volt electrical system)
is bonded to the chassis.
Rick "don't attempt to start it again until you check that ground"
Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
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| Re: [GMCnet] Start problem [message #64555 is a reply to message #64508] |
Mon, 16 November 2009 18:52 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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You need to run (sorrry Ken B.) a 10 ga wire from a keyed source on
the fuse block to the 12vdc connection on the HEI unit. You hooked
the yellow and purple wires up OK but that will just provide 12VDC
during the start cycle, not the run cycle.
On Mon, Nov 16, 2009 at 1:33 PM, Dennis <dps@olypen.com> wrote:
> I have a start problem and need some help understanding what is happening.
>
> The vehicle is a 1973 23 foot GMC motorhome, that has been retrofitted with HEI.
>
> The transmission was out to replace the flex-plate, which had cracked. The flex plate is now fixed.
>
> The transmission mechanic said that they had trouble getting it to start, and had to tap on the starter solenoid to get it to start, and that I may need to replace the starter soon. This is a new problem that I have not experienced before.
>
> It started OK at the transmission shop after the flex plate work was done.... and drove home fine.
>
> But then, as predicted by the transmission mechanic, the starter would not start the motorhome. Tapping on the starter did not help.
>
> After replacing the starter with a re-built unit the vehicle starts when the key is in "start" position, but as soon as the key is returned to "run" the engine quits.
>
> When replacing the starter, the Yellow wire was returned to the R (resistor wire) terminal, which I understand is not used on HEI, but it was connected to the old starter.
> The purple wire was returned to the "S" (start) terminal. Connections are good.
>
> Is there an easy way to diagnose and solve this problem?
>
> Thanks in advance.
>
>
> Dennis Schosboek
> Port Angeles, WA
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: [GMCnet] Start problem [message #64715 is a reply to message #64555] |
Wed, 18 November 2009 00:33 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| Steven Ferguson wrote on Mon, 16 November 2009 18:52 |
You need to run (sorrry Ken B.) a 10 ga wire from a keyed source on
the fuse block to the 12vdc connection on the HEI unit. You hooked
the yellow and purple wires up OK but that will just provide 12VDC
during the start cycle, not the run cycle.
On Mon, Nov 16, 2009 at 1:33 PM, Dennis <dps@olypen.com> wrote:
> I have a start problem and need some help understanding what is happening.
>
> The vehicle is a 1973 23 foot GMC motorhome, that has been retrofitted with HEI.
>
> The transmission was out to replace the flex-plate, which had cracked. The flex plate is now fixed.
>
> The transmission mechanic said that they had trouble getting it to start, and had to tap on the starter solenoid to get it to start, and that I may need to replace the starter soon. This is a new problem that I have not experienced before.
>
> It started OK at the transmission shop after the flex plate work was done.... and drove home fine.
>
> But then, as predicted by the transmission mechanic, the starter would not start the motorhome. Tapping on the starter did not help.
>
> After replacing the starter with a re-built unit the vehicle starts when the key is in "start" position, but as soon as the key is returned to "run" the engine quits.
>
> When replacing the starter, the Yellow wire was returned to the R (resistor wire) terminal, which I understand is not used on HEI, but it was connected to the old starter.
> The purple wire was returned to the "S" (start) terminal. Connections are good.
>
> Is there an easy way to diagnose and solve this problem?
>
> Thanks in advance.
>
>
> Dennis Schosboek
> Port Angeles, WA
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
|
Nothing to be sorry about Steve. It will work. It is just over kill.
You could also just run a new wire to replace the resistance one. It connects under the passenger side hood one one end and the other end runs to the HEI +12 terminal.
Before running a new wire I would read the voltage at the HEI and see if it is +12 during run. He may not need the new wire.
I'm wondering if they got the ground screwed up when the trans was out or if they have a starter gear mesh problem with that new flex plate since the problem just appeared since the flex plate was changed.
My last question is where is the engine battery ground cable connected to? It should be connected direct to a bolt on the engine block. The more I think about it, this probably is not a ground issue since it starts when the key is held to the start position. That is the time when the current is highest and the battery voltage is lowest. A bad or missing ground connection should really show up the under cranking loads.
I think I would check the +12 at the HEI and replace or wire around the ignition resistance wire if the +12 volts reads low. This could also be a bad ignition switch. We really need to know what that reading is at the HEI with the key in the run position.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Start problem [message #64735 is a reply to message #64715] |
Wed, 18 November 2009 08:03 |
Terry Skinner
Messages: 379
Registered: January 2004
Karma: 0
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Senior Member |
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Don't forget the ground wire from the base of the distributor to the
block. Ya, I know, over kill. But several times it has cured
intermittent ign problems for me...........Terry
On Tue, Nov 17, 2009 at 10:34 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Steven Ferguson wrote on Mon, 16 November 2009 18:52
>> You need to run (sorrry Ken B.) a 10 ga wire from a keyed source on
>> the fuse block to the 12vdc connection on the HEI unit. You hooked
>> the yellow and purple wires up OK but that will just provide 12VDC
>> during the start cycle, not the run cycle.
>>
>> On Mon, Nov 16, 2009 at 1:33 PM, Dennis <dps@olypen.com> wrote:
>> > I have a start problem and need some help understanding what is happening.
>> >
>> > The vehicle is a 1973 23 foot GMC motorhome, that has been retrofitted with HEI.
>> >
>> > The transmission was out to replace the flex-plate, which had cracked. The flex plate is now fixed.
>> >
>> > The transmission mechanic said that they had trouble getting it to start, and had to tap on the starter solenoid to get it to start, and that I may need to replace the starter soon. This is a new problem that I have not experienced before.
>> >
>> > It started OK at the transmission shop after the flex plate work was done.... and drove home fine.
>> >
>> > But then, as predicted by the transmission mechanic, the starter would not start the motorhome. Tapping on the starter did not help.
>> >
>> > After replacing the starter with a re-built unit the vehicle starts when the key is in "start" position, but as soon as the key is returned to "run" the engine quits.
>> >
>> > When replacing the starter, the Yellow wire was returned to the R (resistor wire) terminal, which I understand is not used on HEI, but it was connected to the old starter.
>> > The purple wire was returned to the "S" (start) terminal. Connections are good.
>> >
>> > Is there an easy way to diagnose and solve this problem?
>> >
>> > Thanks in advance.
>> >
>> >
>> > Dennis Schosboek
>> > Port Angeles, WA
>>
>> Steve Ferguson
>> '76 EII
>> Sierra Vista, AZ
>> Urethane bushing source
>> www.bdub.net/ferguson/
>
> Nothing to be sorry about Steve. It will work. It is just over kill.
>
> You could also just run a new wire to replace the resistance one. It connects under the passenger side hood one one end and the other end runs to the HEI +12 terminal.
>
> Before running a new wire I would read the voltage at the HEI and see if it is +12 during run. He may not need the new wire.
>
> I'm wondering if they got the ground screwed up when the trans was out or if they have a starter gear mesh problem with that new flex plate since the problem just appeared since the flex plate was changed.
>
> My last question is where is the engine battery ground cable connected to? It should be connected direct to a bolt on the engine block. The more I think about it, this probably is not a ground issue since it starts when the key is held to the start position. That is the time when the current is highest and the battery voltage is lowest. A bad or missing ground connection should really show up the under cranking loads.
>
> I think I would check the +12 at the HEI and replace or wire around the ignition resistance wire if the +12 volts reads low. This could also be a bad ignition switch. We really need to know what that reading is at the HEI with the key in the run position.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
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| Re: [GMCnet] Start problem [message #64749 is a reply to message #64508] |
Wed, 18 November 2009 10:15 |
Dennis[1]
Messages: 4
Registered: April 2009
Karma: 0
|
Junior Member |
|
|
Thanks to all of you for sharing a wealth of knowledge and experience for our shared GMC adventure!
Frankly I am having some trouble identifying what is what on the HEI unit. It was added by a PO, and I have no documentation, and there are no letters or symbols that identify the wires. Grounding wires might be the culprit. From the front I can see what appears to be a severed black wire that terminates on a body ground point just inboard and above the house and start batteries, which are both located in the right front corner of the motorhome on this early 23 foot model. I only found one end of the wire. The other end might go to something important!
The weather has been windy and wet with local flooding and my RV parking is outside. While I am motivated to fix it, by the time I get home from work, it is dark and wet and my personal comfort has taken a higher priority. I'll get to spend some time on it this weekend when I can work on it in the light.
I will let you know how it goes.
Thanks.
Dennis Schosboek
Port Angeles, WA
--------- Original Message --------
From: Ken Burton <n9cv@comcast.net>
To: gmclist <gmclist@temp.gmcnet.org>
Subject: Re: [GMCnet] Start problem
Date: Wed, 18 Nov 2009 00:34:00 -0600
Steven Ferguson wrote on Mon, 16 November 2009 18:52
> You need to run (sorrry Ken B.) a 10 ga wire from a keyed source on
> the fuse block to the 12vdc connection on the HEI unit. You hooked
> the yellow and purple wires up OK but that will just provide 12VDC
> during the start cycle, not the run cycle.
>
> On Mon, Nov 16, 2009 at 1:33 PM, Dennis <dps@olypen.com> wrote:
> > I have a start problem and need some help understanding what is
happening.
> >
> > The vehicle is a 1973 23 foot GMC motorhome, that has been
retrofitted with HEI.
> >
> > The transmission was out to replace the flex-plate, which had
cracked. The flex plate is now fixed.
> >
> > The transmission mechanic said that they had trouble getting it to
start, and had to tap on the starter solenoid to get it to start, and that I may
need to replace the starter soon. This is a new problem that I have not
experienced before.
> >
> > It started OK at the transmission shop after the flex plate work was
done.... and drove home fine.
> >
> > But then, as predicted by the transmission mechanic, the starter
would not start the motorhome. Tapping on the starter did not help.
> >
> > After replacing the starter with a re-built unit the vehicle starts
when the key is in "start" position, but as soon as the key is
returned to "run" the engine quits.
> >
> > When replacing the starter, the Yellow wire was returned to the R
(resistor wire) terminal, which I understand is not used on HEI, but it was
connected to the old starter.
> > The purple wire was returned to the "S" (start) terminal.
Connections are good.
> >
> > Is there an easy way to diagnose and solve this problem?
> >
> > Thanks in advance.
> >
> >
> > Dennis Schosboek
> > Port Angeles, WA
>
> Steve Ferguson
> '76 EII
> Sierra Vista, AZ
> Urethane bushing source
> www.bdub.net/ferguson/
Nothing to be sorry about Steve. It will work. It is just over kill.
You could also just run a new wire to replace the resistance one. It connects
under the passenger side hood one one end and the other end runs to the HEI +12
terminal.
Before running a new wire I would read the voltage at the HEI and see if it is
+12 during run. He may not need the new wire.
I'm wondering if they got the ground screwed up when the trans was out or if
they have a starter gear mesh problem with that new flex plate since the problem
just appeared since the flex plate was changed.
My last question is where is the engine battery ground cable connected to? It
should be connected direct to a bolt on the engine block. The more I think
about it, this probably is not a ground issue since it starts when the key is
held to the start position. That is the time when the current is highest and
the battery voltage is lowest. A bad or missing ground connection should
really show up the under cranking loads.
I think I would check the +12 at the HEI and replace or wire around the
ignition resistance wire if the +12 volts reads low. This could also be a bad
ignition switch. We really need to know what that reading is at the HEI with
the key in the run position.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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List Information and Subscription Options:
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| Re: [GMCnet] Start problem [message #64750 is a reply to message #64508] |
Wed, 18 November 2009 10:15 |
Dennis[1]
Messages: 4
Registered: April 2009
Karma: 0
|
Junior Member |
|
|
Thanks to all of you for sharing a wealth of knowledge and experience for our shared GMC adventure!
Frankly I am having some trouble identifying what is what on the HEI unit. It was added by a PO, and I have no documentation, and there are no letters or symbols that identify the wires. Grounding wires might be the culprit. From the front I can see what appears to be a severed black wire that terminates on a body ground point just inboard and above the house and start batteries, which are both located in the right front corner of the motorhome on this early 23 foot model. I only found one end of the wire. The other end might go to something important!
The weather has been windy and wet with local flooding and my RV parking is outside. While I am motivated to fix it, by the time I get home from work, it is dark and wet and my personal comfort has taken a higher priority. I'll get to spend some time on it this weekend when I can work on it in the light.
I will let you know how it goes.
Thanks.
Dennis Schosboek
Port Angeles, WA
--------- Original Message --------
From: Ken Burton <n9cv@comcast.net>
To: gmclist <gmclist@temp.gmcnet.org>
Subject: Re: [GMCnet] Start problem
Date: Wed, 18 Nov 2009 00:34:00 -0600
Steven Ferguson wrote on Mon, 16 November 2009 18:52
> You need to run (sorrry Ken B.) a 10 ga wire from a keyed source on
> the fuse block to the 12vdc connection on the HEI unit. You hooked
> the yellow and purple wires up OK but that will just provide 12VDC
> during the start cycle, not the run cycle.
>
> On Mon, Nov 16, 2009 at 1:33 PM, Dennis <dps@olypen.com> wrote:
> > I have a start problem and need some help understanding what is
happening.
> >
> > The vehicle is a 1973 23 foot GMC motorhome, that has been
retrofitted with HEI.
> >
> > The transmission was out to replace the flex-plate, which had
cracked. The flex plate is now fixed.
> >
> > The transmission mechanic said that they had trouble getting it to
start, and had to tap on the starter solenoid to get it to start, and that I may
need to replace the starter soon. This is a new problem that I have not
experienced before.
> >
> > It started OK at the transmission shop after the flex plate work was
done.... and drove home fine.
> >
> > But then, as predicted by the transmission mechanic, the starter
would not start the motorhome. Tapping on the starter did not help.
> >
> > After replacing the starter with a re-built unit the vehicle starts
when the key is in "start" position, but as soon as the key is
returned to "run" the engine quits.
> >
> > When replacing the starter, the Yellow wire was returned to the R
(resistor wire) terminal, which I understand is not used on HEI, but it was
connected to the old starter.
> > The purple wire was returned to the "S" (start) terminal.
Connections are good.
> >
> > Is there an easy way to diagnose and solve this problem?
> >
> > Thanks in advance.
> >
> >
> > Dennis Schosboek
> > Port Angeles, WA
>
> Steve Ferguson
> '76 EII
> Sierra Vista, AZ
> Urethane bushing source
> www.bdub.net/ferguson/
Nothing to be sorry about Steve. It will work. It is just over kill.
You could also just run a new wire to replace the resistance one. It connects
under the passenger side hood one one end and the other end runs to the HEI +12
terminal.
Before running a new wire I would read the voltage at the HEI and see if it is
+12 during run. He may not need the new wire.
I'm wondering if they got the ground screwed up when the trans was out or if
they have a starter gear mesh problem with that new flex plate since the problem
just appeared since the flex plate was changed.
My last question is where is the engine battery ground cable connected to? It
should be connected direct to a bolt on the engine block. The more I think
about it, this probably is not a ground issue since it starts when the key is
held to the start position. That is the time when the current is highest and
the battery voltage is lowest. A bad or missing ground connection should
really show up the under cranking loads.
I think I would check the +12 at the HEI and replace or wire around the
ignition resistance wire if the +12 volts reads low. This could also be a bad
ignition switch. We really need to know what that reading is at the HEI with
the key in the run position.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Start problem [message #64761 is a reply to message #64735] |
Wed, 18 November 2009 12:04 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| Terry Skinner wrote on Wed, 18 November 2009 08:03 |
Don't forget the ground wire from the base of the distributor to the
block. Ya, I know, over kill. But several times it has cured
intermittent ign problems for me...........Terry
|
Good point. I had forgotten about that one.
That aluminum (pot metal) distributor will corrode or oxidize over time and fail to make a good electrical connection to the steel block. Adding the wire bypasses / eliminates the problem.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Start problem [message #64764 is a reply to message #64722] |
Wed, 18 November 2009 12:23 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
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| GMCWiperMan wrote on Wed, 18 November 2009 05:17 |
Welcome back, Ken. You must have had an "interesting" trip. Laurie kept us
posted that you were still kicking, but not much about your frustrations.
Ken H.
|
Actually I had a very good trip and attended a very good 49er rally in Port Costa, CA. I also delivered an SOB plus some heavy GMC parts to the west coast.
The only frustrations I had was my laptop decided to lock up the second or third day. I think the CPU bit the dust. I have not torn into it yet. Also my cell phone quit so I stopped at Verizon in SLC and got a new one for free.
I made the trip without plates on the vehicle which was completely legal but I was continuously avoiding the police so I would not get stopped and have to explain. I did have to stop upon entering UTAH and explain to them. That only delayed me about 2 minutes at the port of entry weigh station.
I had a very good trip both ways. I rode the Amtrak back to Chicago. I met a few new people en-route.
We had PAPA Johns deliver Pizzas late one evening to the train at a stop in Nevada. We called ahead and the delivery guy was standing on the platform with 7 pizzas when we arrived.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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