Home » Public Forums » GMCnet » [GMCnet] Return from GMCES Dillard (Pt.2)
| [GMCnet] Return from GMCES Dillard (Pt.2) [message #92067] |
Thu, 15 July 2010 19:17  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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After John & Linda got away Tuesday morning, I went back to the GMC. The
ground fault was still there, but when I looked more closely, I realized
that I really had NOT created a short there. It was soon apparent that the
short was between the power and ground leads to the VSS, which I had mounted
on the governor 3+ years ago.
On the workbench I discovered that the power, ground, and signal leads in
the VSS cable were all firmly melted together -- no one could be separated
from the others without baring its wire. After stripping down to the last
3/4" of wire before the potted VSS, I decided I'd better open the VSS's case
to replace the wires completely.
The four rivets holding the case together drilled & punched out easily,
revealing the guts of the thing. I've always wondered how it worked; now I
know: There is a shaft all the way through the case, with a 1/4" thick, 1"
round ferrite magnet secured to it. As the magnet rotates, the N & S poles
pass the end of a nylon tube into which is potted a Hall Effect sensor at
the inner end and the 3 wires at the outer end. Since I could not find a
compass, I made one from a straightened paper clip magnetized by stroking it
with a pick-up tool's magnet. Hung from a string, that confirmed that the
rotating wheel contains only one magnet -- single N & S poles.
Since this is a 4-pulse VSS (produces 4 pulses per revolution), producing
4000 (4 times the US standard 1000 speedometer cable revolutions per mile),
and the magnet has only two poles, the production of the four pulses is
handled by the sensor electronics. There are several methods by which that
could be accomplished, but the HOW is really of no consequence to us.
Since the wires were potted into the sensor module, I had to solder new
leads to the short stubs left when I trimmed the original wires; fortunately
there was no short among them. I added new high temperature wires, potted
them and enclosed them in 3 layers of heat-shrink tubing. Long 6-32 screws,
bradded to prevent loosening, replaced the rivets holding the case together.
I've driven the GMC around the house to its regular home, but I haven't
tested it on the road to confirm the efficacy of the repair. There should
be no problem.
This exercise did clear up a curious situation I've had ever since I added
VSS to the EFI: My VDO speedometer can be set for any pulse rate up to
115,000 pulses per mile, so calibration was easy -- I matched the GPS's
readout and didn't worry about the pulse rate. When I added a divide-by-two
circuit to provide the 2000 ppm required by the EFI, I was surprised to find
that the What's Up Display speed indication (part of the EBL Flash upgrade)
was about 15% higher than that on the VDO. For several months I've been
trying to figure out how I could get such consistent noise into the signal.
Yesterday, while hunting a short speedometer cable to allow me to move the
VSS to a cooler location, I came across an item I didn't reinstall when I
installed the VDO speedometer: The ratio adapter which corrected the
mechanical speedometer for the change from 3.07 to 3.55 final drive ratio.
Ah! Ha! 3.55/3.07=1.156! That's where my 15% WUD speed error came from!
Gosh that's embarrassing! Such a simple explanation to cost me so much
un-affordable hair loss! The latest version of the EBL Flash software
allows the VSS input pulse rate to be set to other than the standard 2000
ppm so I'll be able to eliminate the divide-by-two circuit AND the speed
error.
All's well that ends well.
Sorry for consuming so much bandwidth, but I had a LOT of fun to report. :-)
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
_______________________________________________
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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: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92075 is a reply to message #92067] |
Thu, 15 July 2010 19:52  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Ken,
Its good to hear that even you do some things then and finger it out later
when your rethinking about it.
I'm younger than you by several years, but I'm catching up.
On Thu, Jul 15, 2010 at 5:17 PM, Ken Henderson <hend4800@bellsouth.net>wrote:
> After John & Linda got away Tuesday morning, I went back to the GMC. The
> ground fault was still there, but when I looked more closely, I realized
> that I really had NOT created a short there. It was soon apparent that the
> short was between the power and ground leads to the VSS, which I had
> mounted
> on the governor 3+ years ago.
>
> On the workbench I discovered that the power, ground, and signal leads in
> the VSS cable were all firmly melted together -- no one could be separated
> from the others without baring its wire. After stripping down to the last
> 3/4" of wire before the potted VSS, I decided I'd better open the VSS's
> case
> to replace the wires completely.
>
> The four rivets holding the case together drilled & punched out easily,
> revealing the guts of the thing. I've always wondered how it worked; now I
> know: There is a shaft all the way through the case, with a 1/4" thick, 1"
> round ferrite magnet secured to it. As the magnet rotates, the N & S poles
> pass the end of a nylon tube into which is potted a Hall Effect sensor at
> the inner end and the 3 wires at the outer end. Since I could not find a
> compass, I made one from a straightened paper clip magnetized by stroking
> it
> with a pick-up tool's magnet. Hung from a string, that confirmed that the
> rotating wheel contains only one magnet -- single N & S poles.
>
> Since this is a 4-pulse VSS (produces 4 pulses per revolution), producing
> 4000 (4 times the US standard 1000 speedometer cable revolutions per mile),
> and the magnet has only two poles, the production of the four pulses is
> handled by the sensor electronics. There are several methods by which that
> could be accomplished, but the HOW is really of no consequence to us.
>
> Since the wires were potted into the sensor module, I had to solder new
> leads to the short stubs left when I trimmed the original wires;
> fortunately
> there was no short among them. I added new high temperature wires, potted
> them and enclosed them in 3 layers of heat-shrink tubing. Long 6-32
> screws,
> bradded to prevent loosening, replaced the rivets holding the case
> together.
>
> I've driven the GMC around the house to its regular home, but I haven't
> tested it on the road to confirm the efficacy of the repair. There should
> be no problem.
>
> This exercise did clear up a curious situation I've had ever since I added
> VSS to the EFI: My VDO speedometer can be set for any pulse rate up to
> 115,000 pulses per mile, so calibration was easy -- I matched the GPS's
> readout and didn't worry about the pulse rate. When I added a
> divide-by-two
> circuit to provide the 2000 ppm required by the EFI, I was surprised to
> find
> that the What's Up Display speed indication (part of the EBL Flash upgrade)
> was about 15% higher than that on the VDO. For several months I've been
> trying to figure out how I could get such consistent noise into the signal.
>
> Yesterday, while hunting a short speedometer cable to allow me to move the
> VSS to a cooler location, I came across an item I didn't reinstall when I
> installed the VDO speedometer: The ratio adapter which corrected the
> mechanical speedometer for the change from 3.07 to 3.55 final drive ratio.
> Ah! Ha! 3.55/3.07=1.156! That's where my 15% WUD speed error came from!
> Gosh that's embarrassing! Such a simple explanation to cost me so much
> un-affordable hair loss! The latest version of the EBL Flash software
> allows the VSS input pulse rate to be set to other than the standard 2000
> ppm so I'll be able to eliminate the divide-by-two circuit AND the speed
> error.
>
> All's well that ends well.
>
> Sorry for consuming so much bandwidth, but I had a LOT of fun to report.
> :-)
>
> Ken H.
> Americus, GA
> '76 X-Birchaven
> www.gmcwipersetc.com
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
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] Return from GMCES Dillard (Pt.2) [message #92127 is a reply to message #92067] |
Thu, 15 July 2010 23:58 |
Marsh Wilkes
Messages: 155
Registered: January 2004
Karma: -3
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Senior Member |
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Hi Ken,
Cool, sounds like fun, wish I could have been there.
You all DID eat at the Dillard House, right?
Marsh "needen to clean the tanks and put a tag on Miss Smokey" Wilkes
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: "gmclist" <gmclist@temp.gmcnet.org>
Sent: Thursday, July 15, 2010 8:17 PM
Subject: [GMCnet] Return from GMCES Dillard (Pt.2)
> After John & Linda got away Tuesday morning, I went back to the GMC. The
> ground fault was still there, but when I looked more closely, I realized
> that I really had NOT created a short there. It was soon apparent that
> the
> short was between the power and ground leads to the VSS, which I had
> mounted
> on the governor 3+ years ago.
>
> On the workbench I discovered that the power, ground, and signal leads in
> the VSS cable were all firmly melted together -- no one could be separated
> from the others without baring its wire. After stripping down to the last
> 3/4" of wire before the potted VSS, I decided I'd better open the VSS's
> case
> to replace the wires completely.
>
> The four rivets holding the case together drilled & punched out easily,
> revealing the guts of the thing. I've always wondered how it worked; now
> I
> know: There is a shaft all the way through the case, with a 1/4" thick,
> 1"
> round ferrite magnet secured to it. As the magnet rotates, the N & S
> poles
> pass the end of a nylon tube into which is potted a Hall Effect sensor at
> the inner end and the 3 wires at the outer end. Since I could not find a
> compass, I made one from a straightened paper clip magnetized by stroking
> it
> with a pick-up tool's magnet. Hung from a string, that confirmed that the
> rotating wheel contains only one magnet -- single N & S poles.
>
> Since this is a 4-pulse VSS (produces 4 pulses per revolution), producing
> 4000 (4 times the US standard 1000 speedometer cable revolutions per
> mile),
> and the magnet has only two poles, the production of the four pulses is
> handled by the sensor electronics. There are several methods by which
> that
> could be accomplished, but the HOW is really of no consequence to us.
>
> Since the wires were potted into the sensor module, I had to solder new
> leads to the short stubs left when I trimmed the original wires;
> fortunately
> there was no short among them. I added new high temperature wires, potted
> them and enclosed them in 3 layers of heat-shrink tubing. Long 6-32
> screws,
> bradded to prevent loosening, replaced the rivets holding the case
> together.
>
> I've driven the GMC around the house to its regular home, but I haven't
> tested it on the road to confirm the efficacy of the repair. There should
> be no problem.
>
> This exercise did clear up a curious situation I've had ever since I added
> VSS to the EFI: My VDO speedometer can be set for any pulse rate up to
> 115,000 pulses per mile, so calibration was easy -- I matched the GPS's
> readout and didn't worry about the pulse rate. When I added a
> divide-by-two
> circuit to provide the 2000 ppm required by the EFI, I was surprised to
> find
> that the What's Up Display speed indication (part of the EBL Flash
> upgrade)
> was about 15% higher than that on the VDO. For several months I've been
> trying to figure out how I could get such consistent noise into the
> signal.
>
> Yesterday, while hunting a short speedometer cable to allow me to move the
> VSS to a cooler location, I came across an item I didn't reinstall when I
> installed the VDO speedometer: The ratio adapter which corrected the
> mechanical speedometer for the change from 3.07 to 3.55 final drive ratio.
> Ah! Ha! 3.55/3.07=1.156! That's where my 15% WUD speed error came from!
> Gosh that's embarrassing! Such a simple explanation to cost me so much
> un-affordable hair loss! The latest version of the EBL Flash software
> allows the VSS input pulse rate to be set to other than the standard 2000
> ppm so I'll be able to eliminate the divide-by-two circuit AND the speed
> error.
>
> All's well that ends well.
>
> Sorry for consuming so much bandwidth, but I had a LOT of fun to report.
> :-)
>
> Ken H.
> Americus, GA
> '76 X-Birchaven
> www.gmcwipersetc.com
> _______________________________________________
> 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] Return from GMCES Dillard (Pt.2) [message #92145 is a reply to message #92127] |
Fri, 16 July 2010 07:16 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Oh yeah, the Dillard house was a MUST. SHE and I celebrated our 51st
anniversary there for lunch on the 8th. It was the first time we'd been
there in almost 30 years. Not quite like last year's month on Kauai, but
still enough to show her I still care. :-)
But it's an obscene experience: Two old folks at a little table loaded with
2 big breaded pork chops, fried and grilled chicken, big slabs of ham, and
stuffed bell pepper -- just for meats. Not to mention the 3-4 salad items
preceding them, nor the 10 different vegetables accompanying them, nor the
yeast rolls, biscuits, and cornbread, nor the dinner plate full of peach
shortcake and ice cream -- all replenished as necessary (Yeah, right). They
only allow one take-out box per person, but those were stuffed, leaving
another meal for two on the table. We had another couple for lunch the next
day, fed from those two boxes. Made the $18.95 per person a bargain.
For the rally, we had Dillard House take-out. Only 2 meats and <10
vegetables. But everyone was stuffed and we had lunch for everyone the next
day -- plus leftovers. The order for 60 meals should have been for 30.
And every dish was uniquely their recipe and delicious. Don't dare miss the
Dillard House if you're ever within 100 miles of Dillard, GA.
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
On Fri, Jul 16, 2010 at 12:58 AM, Marsh Wilkes <gmc455@comcast.net> wrote:
> Hi Ken,
>
> Cool, sounds like fun, wish I could have been there.
> You all DID eat at the Dillard House, right?
>
> Marsh "needen to clean the tanks and put a tag on Miss Smokey" Wilkes
>
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92219 is a reply to message #92145] |
Fri, 16 July 2010 18:04 |
Don A
Messages: 895
Registered: October 2008
Location: Dallas, TX
Karma: 0
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Senior Member |
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Thanks for the trip reports, Ken
So great to hear of folks actually using their coaches as well as working on them.
And such great results for your Cad upgrade.
Don Adams Dallas, TX
'76 26' Glenbrook, '90 Sidekick
rebuilt by R Archer, powered by J Bounds, Koba
[IMG]http://www.gmcmhphotos.com/photos/data/6109/G2.jpg[/IMG]
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| Re: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92287 is a reply to message #92276] |
Sat, 17 July 2010 15:53 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Bob,
The Cad definitely has more torque than the Olds. Even with a 23', I've
always "known" that I was driving a heavy vehicle "by the seat of my pants".
With the Cad, that feeling is gone -- throttle response is that much
better, even with the same EFI on both engines.
At cruising speed, towing, the difference is not as noticeable. There are
no serious hills between Dillard and here, but a lot of them steep enough to
drop the ElectroMotor II CC set speed by 2-3 mph while towing a 3600-3700#
CRV. John Richardson, with his 26' Avion, not towing had no trouble staying
right with me.
However, I'm convinced that I'm running 5* to possibly 10* too little spark
advance right now. The GMCMH-EFI group are in the midst of an intense
investigation of SA tables and SA latency which indicates that my absence of
spark knock counts is probably due to improper setting of those parameters.
Almost as important to me: The Cadillac is much easier to service than the
Olds: The external oil pump has not yet been important, but could be. Most
importantly, they didn't hang all the accessories on top of each other --
especially with my dual serpentine belts. I managed to build a cam chain
cover leak into my engine. When I get around to fixing it, I'll have to
drain the radiator, remove the two serpentine belts, and unbolt the chain
cover -- bringing the water pump out with it. The PS pump, alternator, and
A/C compressor will be undisturbed (except for loosening the first two for
belt adjustment). That's important to me! :-)
The Cad does run 220*F+, as I'd been warned to expect, even with the good
radiator which kept the 455 "on the thermosat". My fan clutch may not be
working.
I'm NOT planning to go back, even though I don't like the raised engine
hatch (which is not yet finished).
Ken H.
On Sat, Jul 17, 2010 at 1:01 PM, Bob de Kruyff <NEXT2POOL@aol.com> wrote:
>
>
> Ken--overall, how does the Cadillac engine compare to the Olds 455?
> --
> Bob de Kruyff
>
_______________________________________________
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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: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92315 is a reply to message #92287] |
Sat, 17 July 2010 19:52 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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|
Thanks Ken. I definitely understand what you are saying about the accessory drive--the Olds are about as bad as I've ever seen. As far as the temperature goes, I would strongly suspect the fan clutch. My storage neighbor with his 455 has been running hot for years and I asked if he could hear his fan clutch. His answer was no, even though it was new. I'm going through that myself after my original clutch failed a couple of weeks ago. Mine got upto 210 and I was alarmed, so I can't imagine running continuously at 220. Anyway, my neighbor just installed a Napa clutch and for the first time ever, he now hears the clutch engage and cycle. His temp is now running a steady 190. My replacement Hayden severe duty is not coming on and I'm still running 210. I just bought the identical Napa clutch he got and will install it tomorrow. From what I can tell so far, it is identical to the Hayden that I'm unhappy with. We'll see, but I'm suspicious that the calibrations are all over the place even for the same p/n clutches. I may tweak the spring if this trial doesn't go well. Thanks for the feedback!
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92355 is a reply to message #92315] |
Sun, 18 July 2010 07:08 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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Bob,
The NAPA unit is made by Hayden.
On Sat, Jul 17, 2010 at 5:52 PM, Bob de Kruyff <NEXT2POOL@aol.com> wrote:
>
>
> Thanks Ken. I definitely understand what you are saying about the accessory drive--the Olds are about as bad as I've ever seen. As far as the temperature goes, I would strongly suspect the fan clutch. My storage neighbor with his 455 has been running hot for years and I asked if he could hear his fan clutch. His answer was no, even though it was new. I'm going through that myself after my original clutch failed a couple of weeks ago. Mine got upto 210 and I was alarmed, so I can't imagine running continuously at 220. Anyway, my neighbor just installed a Napa clutch and for the first time ever, he now hears the clutch engage and cycle. His temp is now running a steady 190. My replacement Hayden severe duty is not coming on and I'm still running 210. I just bought the identical Napa clutch he got and will install it tomorrow. From what I can tell so far, it is identical to the Hayden that I'm unhappy with. We'll see, but I'm suspicious that the calibrations are all over the pla
> ce even for the same p/n clutches. I may tweak the spring if this trial doesn't go well. Thanks for the feedback!
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> 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] Return from GMCES Dillard (Pt.2) [message #92366 is a reply to message #92355] |
Sun, 18 July 2010 10:17 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
|
|
Yes it appears to be Steve--I read your excellent write-up on the Western States site. I did go to the Hayden website and was surprised at the many variations of fan clutches that appear to be almost identical appearance wise. I'm assuming the differences are calibration. I thought I'd give this clutch a try since it cycles perfectly for my neighbor. I'm going to give it a try this morning. What I don't know is if the cal on this part number is the best one or if he just lucked out and got a good one. I'm suspicious of the latter. Luckily I've gotten good enough at switching these that I can R & R these in about 20 minutes. If this one isn't right, I'll resort to tweaking the spring. I'm starting to realize that many GMC's may be running around with fan clutches that aren't coming on or coming on too late. I was surprised that my neighbor has been running hot for years even though his fan clutch was relatively new. More to come.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Return from GMCES Dillard (Pt.2) [message #92435 is a reply to message #92366] |
Sun, 18 July 2010 16:09 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
|
Senior Member |
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Bob,
Please post your results. Chuck Aulgur played around with
recalibrating the spring on an AC Delco unit and was never able to get
it to work to his satisfaction.
I'll race you on fan clutch replacement. Damn, I'm fast!
On Sun, Jul 18, 2010 at 8:17 AM, Bob de Kruyff <NEXT2POOL@aol.com> wrote:
>
>
> Yes it appears to be Steve--I read your excellent write-up on the Western States site. I did go to the Hayden website and was surprised at the many variations of fan clutches that appear to be almost identical appearance wise. I'm assuming the differences are calibration. I thought I'd give this clutch a try since it cycles perfectly for my neighbor. I'm going to give it a try this morning. What I don't know is if the cal on this part number is the best one or if he just lucked out and got a good one. I'm suspicious of the latter. Luckily I've gotten good enough at switching these that I can R & R these in about 20 minutes. If this one isn't right, I'll resort to tweaking the spring. I'm starting to realize that many GMC's may be running around with fan clutches that aren't coming on or coming on too late. I was surprised that my neighbor has been running hot for years even though his fan clutch was relatively new. More to come.
> --
> Bob de Kruyff
> 78 Eleganza
> Chandler, AZ
> _______________________________________________
> 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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