GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.
Home » Public Forums » GMCnet » need a bit of help with vacuum hose routing / electric wire 1978
need a bit of help with vacuum hose routing / electric wire 1978 [message #313159] Mon, 13 February 2017 18:56 Go to next message
davidlive is currently offline  davidlive   
Messages: 143
Registered: November 2011
Location: Simi valley, Southern Cal...
Karma: -1
Senior Member
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://i3.photobucket.com/albums/y92/DavidLive/1978%20GMC%20motorhome/Marked%20Abc_zpsgkbmrdg2.jpg

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 some 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

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: Mon, 13 February 2017 18:57]

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313163 is a reply to message #313159] Mon, 13 February 2017 20:42 Go to previous messageGo to next message
77Royale   United States
Messages: 461
Registered: June 2014
Location: Mid Michigan
Karma: 6
Senior Member
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

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313165 is a reply to message #313159] Mon, 13 February 2017 21:12 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
Senior Member
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

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313170 is a reply to message #313165] Mon, 13 February 2017 23:18 Go to previous messageGo to next message
davidlive is currently offline  davidlive   
Messages: 143
Registered: November 2011
Location: Simi valley, Southern Cal...
Karma: -1
Senior Member
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

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.

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313172 is a reply to message #313170] Tue, 14 February 2017 05:34 Go to previous messageGo to next message
C Boyd is currently offline  C Boyd   United States
Messages: 2629
Registered: April 2006
Karma: 18
Senior Member
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.


davidlive wrote on Tue, 14 February 2017 00:18
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

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313364 is a reply to message #313159] Thu, 16 February 2017 23:18 Go to previous messageGo to next message
davidlive is currently offline  davidlive   
Messages: 143
Registered: November 2011
Location: Simi valley, Southern Cal...
Karma: -1
Senior Member
I'm slowly getting them figured out

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: Sat, 18 February 2017 15:42]

Report message to a moderator

Re: need a bit of help with vacuum hose routing / electric wire 1978 [message #313436 is a reply to message #313159] Sat, 18 February 2017 15:42 Go to previous message
davidlive is currently offline  davidlive   
Messages: 143
Registered: November 2011
Location: Simi valley, Southern Cal...
Karma: -1
Senior Member
Here's a update, i'm still trying to figure out a few of them



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.

Report message to a moderator

Previous Topic: Re: [GMCnet] Fwd: GMCMI (International) rallies mapped out
Next Topic: 78 LIVES !!!
Goto Forum:
  


Current Time: Tue Nov 05 08:35:42 CST 2024

Total time taken to generate the page: 0.01487 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.1.1.
Copyright ©2001-2021 FUDforum Bulletin Board Software