|
06-25-2022, 05:20 PM
|
#1
|
Winnebago Watcher
Join Date: Jun 2022
Posts: 3
|
Dash Air Actuator question 1988 Chieftain
New to the forum, first post. I recently picked up an '88 Chieftain, p30 chasis, 454 carbureted engine, 22'er. Okay, I've noticed that the vent selector is not working and air only blows from the defrost. There are two vacuum canisters under the hood. One for cruise control and the other for HVAC. There is one hose missing from each and I'm not sure where they come from or go to 🤔. Air blowing from defrost with A/C selected is cold, but it would be very nice if it would blow from the vents, lol. I have two questions: Where should I start? And is it possible to just bypass the vacuum operated actuator and just set it to blow from the vents manually? Thanks in advance for any help.
|
|
|
06-25-2022, 07:19 PM
|
#2
|
Winnebago Master
Join Date: Nov 2018
Location: Pflugerville/Austin, Tx
Posts: 7,371
|
I think you are looking at vaccum lines to srot and that is not likely to be something many will know off the top of their head, so I would go to the library as a cheap spot to look for good solid info.
A repair manual like a Chilton's for your chassis would be my first thought.
If you had broken lines, you might find the other end but if the whole thing is missing, it's hard to guess where to replace a line that is not there to even show how long or where one end fits.
While looking at those lines, it may be prudent to replace any that are original as they are getting really old if they have lasted this long and at the price, I like to head off those nagging things that happen when vacuum lines gets crakcs!
__________________
Richard
Why no RV year, make and floorplan on MY signature as we suggest for others?
I currently DO NOT have one!
|
|
|
06-26-2022, 07:47 AM
|
#3
|
Winnebago Watcher
Join Date: Jun 2022
Posts: 3
|
Quote:
Originally Posted by Morich
I think you are looking at vaccum lines to srot and that is not likely to be something many will know off the top of their head, so I would go to the library as a cheap spot to look for good solid info.
A repair manual like a Chilton's for your chassis would be my first thought.
If you had broken lines, you might find the other end but if the whole thing is missing, it's hard to guess where to replace a line that is not there to even show how long or where one end fits.
While looking at those lines, it may be prudent to replace any that are original as they are getting really old if they have lasted this long and at the price, I like to head off those nagging things that happen when vacuum lines gets crakcs!
|
I get that, hence the second question. Is it possible to just manually direct the air to blow from the dash vents?
|
|
|
06-26-2022, 08:34 AM
|
#4
|
Winnebago Master
Join Date: Nov 2018
Location: Pflugerville/Austin, Tx
Posts: 7,371
|
No idea on that. I suspect not as whatever is stilll working would be trying to move things for what you have now??
My thoughts are that the vacuum changes so many other things like ignition and heat/air that trying to work with open vacuum lines is just not something I've tried.
__________________
Richard
Why no RV year, make and floorplan on MY signature as we suggest for others?
I currently DO NOT have one!
|
|
|
06-27-2022, 08:04 AM
|
#5
|
Winnebago Watcher
Join Date: Jun 2022
Posts: 3
|
Quote:
Originally Posted by Morich
No idea on that. I suspect not as whatever is stilll working would be trying to move things for what you have now??
My thoughts are that the vacuum changes so many other things like ignition and heat/air that trying to work with open vacuum lines is just not something I've tried.
|
My intent is to cap the vacuum ports on the canisters and plug any lines I see open (Which as far as I can tell, are only the two lines forth canisters), if I cannot get them properly run and connected. For temporary purposes, where is the actuator dorm located?
|
|
|
07-03-2022, 06:08 PM
|
#6
|
Winnebago Camper
Join Date: Mar 2016
Posts: 18
|
The vacuum system is pretty simple. A vacuum line from the intake manifold supplies the reservoir tank(s) large fitting, the small fitting on the HVAC tank supplies the back of the HVAC control head. Depending on whats selected on the control will route vacuum to the various plenum doors. Another vacuum line goes from the control head to the heater valve in the line going TO the heater core to shut off water when ac is requested. As a safety measure the default setting is defrost. I have a vacuum schematic for the control head but not sure how to share it here.
__________________
Bill
1991 Winnebago Warrior 23EC Class A
|
|
|
07-04-2022, 09:40 AM
|
#7
|
Winnebago Owner
Join Date: Jul 2020
Posts: 165
|
You've got lots of good replies here. this doesn't directly apply to your first problem, but a testing vacuum gauge and T connector would be relatively inexpensive, to see what you have going on, and as you fix things, and note the the improvements.
The health of an engine, cam, and timing, and wear; all affect what you get, not just the cracked or broken lines.
As you likely know, the engine only creates vacuum at low throttle, and at the high end produces none. There are little check balls so at higher throttle the mentioned vacuum cans don't bleed back out.
Free trivia, I had a GM 6.2 diesel, which was based on the big block gas engine. Diesels don't make vacuum, but the Suburban needed it to run the heater/AC system which was designed for a gas engine. They stuck a vacuum pump in the hole were the distributor would have gone, so it ran on the same shaft as the oil pump did. Of course I found this out when trouble shooting why the heater/defroster vents weren't working. Surprise, a bad pump I didn't know I even had.
__________________
Rick_99037
2005 Winnebago Sightseer 29R Class A
8.1 Workhorse - GM 4 speed
|
|
|
07-04-2022, 12:17 PM
|
#8
|
Winnie-Wise
Join Date: Dec 2019
Location: Kansas
Posts: 391
|
22Chieftan, look at this website for some really good info on RV vacuum HVAC systems. You will have to dig around some on the website but I would bet you will find info that will help you. As Richard mentioned above, most likely the vacuum hoses/lines have rotted with age. They are easy to replace. Next is the vacuum motors/actuators - finding these is hit or miss if you have a bad one. Finally the vacuum control - harder to find a replacement.
https://www.proairllc.com/design-eng...empcon-guides/
__________________
The things you own control your life.
2021 Winnebago Vista 35U towing a 2022 Jeep Cherokee Trailhawk
2010 Cadillac SRX 2003 Itasca Sunova 30B
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|