im stuck please help

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sunbird 92 3.1

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My ac works but its not pushingout as good as it should the ac isnt the problem when i switch it from max to floor or def it doesnt change i heard its a vacuum line but does anybody have a picture or could tell me which one cause ive changed all the ones i thought were bad i have a 1991 pontiac sunbird 3.1 conv please help it worked perfectly fine before but i tore the engine apart to put new heads in it and i think i broke a vac line hut ive looked everywhere
 
There's a vacuum line right up at the firewall under the hood that connects to the switching system. Mine was off all winter and my toes froze! It's kinda hidden. Right under the MAP sensor I think.
 
So it is a vacuum line that causes it to not push out as hard and for it not to switch from def to front or where ever else?
 
Yes , it will cause some doors not to open. ( black plastic Tubing )
On my car ( 2.0) it runs off the intake manifold , along the firewall to the right side of the car. then it travels to the front fender to the vacuum holding ball that is hidden " under" the car right where the evap canister is in the engine compartment. Then it travels back to the right " cubby" where all the relays and the computer harness goes back into the passenger compartment.

Heres some pics to help>>>>>>> ( you can see it by the wiper motor and ps resivior) http://www.pontiacforum.com/pontiac/album.php?albumid=130&pictureid=392

Doug in P.R.:cool:
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Just some food for thought......It could be a blower motor resistor. This can cause it to not switch back and forth between settings. I've seen it on a Ford Ranger and a Chevy S10. In both cases it was the resistor.

Most of the time the blower motor isn't far behind it either.

But seeing as how you pulled the head and it didn't start til then I would check the vaccum line first. There are only 2 lines in the way and they have to be moved a bit to remove the coolant box to remove the alt so if you removed the coolant box and had to lift up those lines like I did you probably broke one.

I think I did the same thing so don't feel bad if you broke it. I am now trying to track down the leak I can hear a hiss when recharging coming from the rear towards the firewall.

Now mines an 88 so it may differ slightly but not by much.

Also push the low pressure valve and see if any oil comes out (push with a screw driver very very quickly) this will tell you if its low on R134-a.
 
Oh yeah forgot to say just trace your lines from the dryer and check each line. The one with oil all over it will be the problem. Or you could just get the UV R134 and put it in and shine a uv light and you'll know where the leak is. If it is in fact caused by a leaky line.

Also check your condenser and compressor. I would just go over the entire AC system just to put my mind at ease of weather or not there is a leak. You will be looking for a weird kind of oil on things.

Also make sure all your fuses and relays are good.

Did you unhook the negative before pulling the head? Unhooking any electrical component with the battery connected can short out relays and fuses.
 
The ac isnt leaking its just the fan isnt pushing air out as hard as it did before and when i switch it from floor to defrost or anything it doesnt change it just pushes out all of them mostly the front
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sunbird 92 3.1 said:
The ac isnt leaking its just the fan isnt pushing air out as hard as it did before and when i switch it from floor to defrost or anything it doesnt change it just pushes out all of them mostly the front
Click to expand...

Yep sounds more like a blower motor resistor then. Since the AC is intact and not leaking. Common signs of that resistor being shot is

unable to switch levels
unable to switch from high to low (blows at the same consistency regardless setting)

The resistor usually is located under the passenger side dash. You may have to remove a panel to access it.

it should look similar to this

http://www.rockauto.com/getimage/ge...//www.rockauto.com/info/FourSeasons/20142.jpg

it will have a connector. If you replace it is almost certain you will have to replace the blower motor because the brushes in the motor over time like to give up so I would do it all in one swoop.

But yeah this just sounds like the resistor shit out and is giving you hell. It is only a 14 dollar part so you wont be out much if it turns out not to be it. But if I was a betting man thats what I would bet on it being.

But anyhow good luck on it let me know how it turns out and what it turns out to be.
 
The blend door is vacuum actuated. My camera died recently but I'll try to remember to take a couple of fish eye shots with my video camera when I get to work tonight. Wait! I'll take the USB Microscope. I need to do some peaking in tight spots anyway. It does better close-ups anyway. The blend door decides which way the air goes. I'm pleased my AC blows cold though it don't mean much topless. I'm working on the new top right now and new suspension parts are coming!

That's R12 in there EC and it's about $70 a pound these days.

You may have a fan issue too but MAX/AC doesn't use the resistor, it's direct high speed to the fan but not if your vacuum leaks. If it won't switch between floor and defrost it's vacuum. You may have a part missing on the vacuum switch. There's a little plastic pin that the vacuum switcher pivots on and it is hard to find. Mine is missing and I get hissing from the switch sometimes.
 
This one doesnt have a hissing sound my other one that caught on fire had that sound as of right now i put a bigger vac line on it n it blows out more now
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