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Question on HVAC controls!

sheffeyva

NAXJA Forum User
Location
Portland, OR
While blindly removing all unnecessary wires and hoses I might have gotten rid of my HVAC vacuum controls!
6970755555_3dc8ef058f.jpg

Is this the two vacuum lines that need to be connected? I only have heat blowing out my defrost by the windshield and I'm assuming these are them. Just wanted to make sure.
 
sure looks like 'em to me!

P.S. small block chevrolet in that one?
Certainly is a "small" block! Just a 2.8l V6 :roflmao:! I put on an edelbrock manifold and holley carb and literally ripped off everything else! Luckily this all works on the 3.4l if I go that route but maybe a SBC in the future. It only has 80k on the motor so I figured I'll run it till it dies then upgrade. I more using this Jeep as a learning project for the suspension since I am coming from the world of Sport Compact cars!
 
Another question is how would I go about connecting these plastic lines to a single vacuum source? For the life of me I can't find fittings to change these for hard to soft lines so I can run them to the intake manifold.
 
the first XJ I ever played with had the same set up! I got it running for someone else and thought I'd seen the last of Cherokees for ever......

A couple years later I had one fall into my lap for a song and the guy I helped with the '86 gave me the lift off it as a "thank you" for helping him get it running (two years after helping)

I'm still running the lift today-- shoulda kept the '86 for spare parts, but still woulda scrapped the 2.8L:shhh:
 
Another question is how would I go about connecting these plastic lines to a single vacuum source? For the life of me I can't find fittings to change these for hard to soft lines so I can run them to the intake manifold.

find some soft line that'll fit snugly over the hard line and a "Y" fitting for the vacuum hose. Run each hose to the "Y" and then into a constant vacuum source. The factory vacuum source was run into a vacuum storage canister (softball like reservoir behind the front bumper) to aid in HVAC operation during times of low engine vacuum.
 
Definitely not rebuilding this sucker when it dies but it has good compression and gets around just fine here in the hills of Portland on 32's and stock 4.10 gears. Probably going to start building a SBC of some kind here soon that way i can just swap when it does die!
 
find some soft line that'll fit snugly over the hard line and a "Y" fitting for the vacuum hose. Run each hose to the "Y" and then into a constant vacuum source. The factory vacuum source was run into a vacuum storage canister (softball like reservoir behind the front bumper) to aid in HVAC operation during times of low engine vacuum.
Would it be fine running to full manifold vacuum or should I fab up a vacuum ball like the factory. I'm getting about 22hg of vacuum at idle.
 
you'd be fine at idle and under cruise conditions (low throttle), but as you've learned, the default position of the air door is defrost. Any time you're "on the throttle" or climbing a hill, you'll lose enough vacuum for it to default to the windshield.

I'd find a small vacuum ball at the boneyard and put it in line.
 
Thanks for all your help! And by the way I used to live in the same area you do. I lived right off of Princess Anne blvd in Virginia Beach. Really miss that area. I graduated high school over in Newport News awhile back also. I've been back there twice to live so far. I love the 7 cities area!
 
The pink one goes to the heater control valve, which is not there. Plug the pink line with a vacline cap 10 cents.

The black goes to the vac ball, junkyard $5. The vac ball needs a vac SOURCE. Usually T'd off the cruise servo, also looks like deleted or never there. You can run a source line from the intake manifold.
 
The pink one goes to the heater control valve, which is not there. Plug the pink line with a vacline cap 10 cents.

The black goes to the vac ball, junkyard $5. The vac ball needs a vac SOURCE. Usually T'd off the cruise servo, also looks like deleted or never there. You can run a source line from the intake manifold.


vary good point^^ I failed to pay attention to the fact that only one line goes into the HVAC-- cap the pink one off and avoid the "Y" connector and extra headaches.....
 
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