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Re: [GMCnet] need a bit of help with vacuum hose routing / electric wire 1978 [message #313365] Thu, 16 February 2017 23:30 Go to next message
James Hupy is currently offline  James Hupy   United States
Messages: 6806
Registered: May 2010
Karma: -62
Senior Member
In the carb. section of the service manual, there is a illustration of the
carb and all the vacuum ports on it. Each port is assigned an alphabet
letter, and where the hose goes. It goes along with the emissions section.
In this case, R.T.F.M. is the best advice I can think of. I am presently in
California attending to funeral arrangements for my step-daughter, and am
not near my laptop or hardcopy of the manual or I would look it up and give
you the page numbers. Sorry.
Jim Hupy

On Feb 16, 2017 9:19 PM, "David Morrison" wrote:

Here's a update, i'm still trying to figure out a few of them

i found the solenoid, and i believe i found the vacuum delay so here's what
i goten figured out so far

A - Solved/Repaired

B - Hose Connection to vacuum Which i'm believe i'm missing unless this is
it ?
(http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
20170214_164900_zpsbw0kprpm.jpg.html) and then to hose connection G

C - Solved/Repaired
D - Solved/Repaired
E - Solved/Repaired
F - Solved/Repaired
G - (see above note B)

H - Unknown hose connection - is this the connection to air filter ?
(http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
20170213_153643_zpsrfevwezo.jpg.html)
some links to better show it's position in the base of the rear (facing) of
the carburator
(http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
20170214_165127_zpsryrtrll9.jpg.html) & this next one it's hidden a bit by
the bracket (http://s3.photobucket.com/user/DavidLive/media/1978%
20GMC%20motorhome/IMG_20170214_165147_zpsskyyyhzk.jpg.html)

I - Unknown Connection, My understanding is it goes to the vacuum can, but
i'm not sure where it's located yet ?
http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
20170214_165035_zpsuw8y8yhu.jpg.html

J - Unknown Connection for cruise control
http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
20170214_165057_zpsaiwzlbvj.jpg.html

Thanks David
--
1974 G-M-C Painted Desert #136
"Oversteer is when you hit the wall with the rear of the car, understeer is
when you hit the wall with the front of the car. Hp is how fast you hit
the wall, and torque is how far you take the wall with you when you hit it."

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Re: [GMCnet] need a bit of help with vacuum hose routing / electric wire 1978 [message #313386 is a reply to message #313365] Fri, 17 February 2017 12:05 Go to previous messageGo to next message
powwerjon is currently offline  powwerjon   United States
Messages: 849
Registered: March 2013
Karma: -2
Senior Member
You should look in the 77-78 supplement manual X7725 on page 6T-4, Figure 5 may be of some help. The green item that you show in the picture is the vacuum delay valve.

J.R. Wright
GMC GreatLaker
Newsletter Editor/Publisher
Tech Editor
78 Buskirk 30' Stretch
75 Avion Under Reconstruction
Michigan

> On Feb 16, 2017, at 10:30 PM, James Hupy wrote:
>
> In the carb. section of the service manual, there is a illustration of the
> carb and all the vacuum ports on it. Each port is assigned an alphabet
> letter, and where the hose goes. It goes along with the emissions section.
> In this case, R.T.F.M. is the best advice I can think of. I am presently in
> California attending to funeral arrangements for my step-daughter, and am
> not near my laptop or hardcopy of the manual or I would look it up and give
> you the page numbers. Sorry.
> Jim Hupy
>
> On Feb 16, 2017 9:19 PM, "David Morrison" wrote:
>
> Here's a update, i'm still trying to figure out a few of them
>
> i found the solenoid, and i believe i found the vacuum delay so here's what
> i goten figured out so far
>
> A - Solved/Repaired
>
> B - Hose Connection to vacuum Which i'm believe i'm missing unless this is
> it ?
> (http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
> 20170214_164900_zpsbw0kprpm.jpg.html) and then to hose connection G
>
> C - Solved/Repaired
> D - Solved/Repaired
> E - Solved/Repaired
> F - Solved/Repaired
> G - (see above note B)
>
> H - Unknown hose connection - is this the connection to air filter ?
> (http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
> 20170213_153643_zpsrfevwezo.jpg.html)
> some links to better show it's position in the base of the rear (facing) of
> the carburator
> (http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
> 20170214_165127_zpsryrtrll9.jpg.html) & this next one it's hidden a bit by
> the bracket (http://s3.photobucket.com/user/DavidLive/media/1978%
> 20GMC%20motorhome/IMG_20170214_165147_zpsskyyyhzk.jpg.html)
>
> I - Unknown Connection, My understanding is it goes to the vacuum can, but
> i'm not sure where it's located yet ?
> http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
> 20170214_165035_zpsuw8y8yhu.jpg.html
>
> J - Unknown Connection for cruise control
> http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_
> 20170214_165057_zpsaiwzlbvj.jpg.html
>
> Thanks David
> --
> 1974 G-M-C Painted Desert #136
> "Oversteer is when you hit the wall with the rear of the car, understeer is
> when you hit the wall with the front of the car. Hp is how fast you hit
> the wall, and torque is how far you take the wall with you when you hit it."
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org


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Re: [GMCnet] need a bit of help with vacuum hose routing / electric wire 1978 [message #313390 is a reply to message #313365] Fri, 17 February 2017 14:51 Go to previous message
davidlive is currently offline  davidlive   
Messages: 143
Registered: November 2011
Location: Simi valley, Southern Cal...
Karma: -1
Senior Member
Thanks for the info that is the vacuum delay valve, as i've been unable to buy one anywhere and I've been pouring over that manual, and found that, which helped me with most of them, but these ones aren't there on that page.

Unknown hose connection - is this the connection to air filter ?
some links to better show it's position in the base of the rear (facing) of the carburator (http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170214_165127_zpsryrtrll9.jpg.html) & this next one it's hidden a bit by the bracket (http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170214_165147_zpsskyyyhzk.jpg.html)

Unknown Connection, this is coming off the intake maniford vacuum, i'm guessing it's for the vent controls, but i'm not sure where it's going to yet
http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170214_165035_zpsuw8y8yhu.jpg.html

Unknown Connection for cruise control http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170214_165057_zpsaiwzlbvj.jpg.html

Thanks David


78 Royal #749
74 #136
Oversteer is when you hit the wall with the rear of the car, understeer is when you hit the wall with the front of the car. Hp is how fast you hit the wall, and torque is how far you take the wall with you when you hit it.

[Updated on: Fri, 17 February 2017 14:52]

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