need a bit of help with vacuum hose routing / electric wire 1978

davidlive

davidlive

Member
Nov 19, 2011
216
27
18
Simi Valley, California
Been cleaning up the engine bay of this 1978 Royal with a 403 engine I recently aqquired last week from rat crap and chew... which has damaged hoses
and wires
I marked the spots on the picture with letters to help me identify where some hoses/wires need to go

http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/Marked%20Abc_zpsgkbmrdg2.jpg.html

A - I believe this is the connection for the temperature reading ? which would go to wire E or F
B - Hose Connection to i believe a check valve? and then to hose connection G
C - Hose Connection to something i'm unknown device which would then connect to D
D - (see above note C)
E - Broken Wire connection
F - Broken Wire connection
G - (see above note B)
H - Unknown hose connection
I - Unknown Connection
J - Hose hanging on passenger side of engine, unknown where to connect

I know the hose from the middle connection of the tvs to the distributor is missing and will be replaced as well
Any thoughts at what is shown, and i have closer up pictures as well from different angles (links only)
Rear http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170213_153446_zpsdyzjw2tr.jpg.html
Front http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170213_153459_zps4sqx02gv.jpg.html
Drivers http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170213_153508_zpslt46fiw0.jpg.html
Passenger http://s3.photobucket.com/user/DavidLive/media/1978%20GMC%20motorhome/IMG_20170213_153517_zpscxqd1cmm.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."
 
If you have the 77-78 Maintenance manual there is a good write up and exploded views of the vacuum routing. Being that you probably have a CA
emissions coach and possibly need to keep the emissions stuff intact I would take a look at those pages. The lines are a bit different for the CA
stuff.

http://www.bdub.net/factory-manuals.html

Download X7725 and take a look at page 6T-6 That has the 78 California engine emission control vacuum hose schematic. That should take care of most
of it.

Good Luck and thanks for rescuing another Coach. A Royale at that.


--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
Looks like Cali emmisions with the idle throttle kicker. Just follow the diagram and run one new hose at a time. Pic is pretty small but "I" is just
the clean filtered supply air for the choke heater. It draws from rear area of carb in free air.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
i found it in the pdf, as you suggested, and it looks like the non-ca emission control hoses (even though i'm in ca), but that means i'm missing the
solenoid valve (i'm not sure where it would be mounted on the engine), and i'm missing the vacuum delay valve, and i'm not sure where H, J and I would
be going to ?

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."
 
Sir, the solenoid valve is on the right front of the engine. It has vacuum lines running thru it thru the black can on the front left of head next to
temp sender and goes into dashpot on LF of carb. Solenoid is activated by electrical signal from neutral safety switch when in drive. It idles up
carb when in drive only. This is 403 only, last one I had trouble with I plugged vacuum control at carb, unplugged the electric solenoid, backed off
the dashpot and used idle screw to adjust idle. The delay valve is a small block inline to top back of carb to delay the dashpot. The small hard
vacuum line with bell shaped connector goes out front to vacuum can which controls dash air controls.

> i found it in the pdf, as you suggested, and it looks like the non-ca emission control hoses (even though i'm in ca), but that means i'm missing
> the solenoid valve (i'm not sure where it would be mounted on the engine), and i'm missing the vacuum delay valve, and i'm not sure where H, J and I
> would be going to ?
>
> Thanks David

--
C. Boyd
76 Crestmont
East Tennessee
 
Call me if you want help.

> i found it in the pdf, as you suggested, and it looks like the non-ca
> emission control hoses (even though i'm in ca), but that means i'm missing
> the
> solenoid valve (i'm not sure where it would be mounted on the engine), and
> i'm missing the vacuum delay valve, and i'm not sure where H, J and I would
> be going to ?
>
> 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
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
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."
 
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

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
 
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

>
> 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
>

>
> 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
 
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.

H - 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)

I - 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

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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