weird A/C problem

[mujaman]

first of all, the problem is not really with the A/C, its with the fan system that blows the air through the vents (so it happens with heat, A/C, and just vented in outside air). what happens is this:

whenever i am constantly on the gas for any amount of time (over 30 seconds or so), something back inside the dash closes off and cuts out all the airflow out of all the vents (floor and main). as soon as i let off the gas for just a second or two, i can hear something (some sort of valve or whatever) pop back open in the dash and the airflow returns. then as soon as i stay on the gas again, it cuts out... and so on. the cycle just continues itself.

any ideas? any easy fixes?

thanks...

 

[Saurian]

Vacuum problem; when you are on the gas, vacuum is building up, either a regulator or one of the vacuum motors that control airflow is broken.

Had the same thing happen in my Reliant, never did find out what it was, though...

 

[90Xjay]

scotty.... must..hunt.....for....loose hose.....Spoke, Bones..
alright, enough with the Star Tec fix:lol: :lol:

If you don't see any loose or disconnected vacuum lines under the hood, try some carb spray while engine runs. spray a little around vacuum connectors and if the engine speed picks up, that means a vacuum leak sucked in the spray through a leak.
Vacuum leaks...well... they suck... and they can be hard to find.

Good Luck

 

[88Wrangles]

Vacuum problem; when you are on the gas, vacuum is building up, either a regulator or one of the vacuum motors that control airflow is broken.

Actuallye, You have less vacuum when you're on the gas. You have the most vacuum at idle...and none at wide open throttle.


Ya, your blend door is most likely vacuum actuated and you've got some kind of a problem with a line or something.

 

[Saurian]

Oooh, I stand corrected... At least I knew it was vacuum related

 

[90Xjay]

what year is it??
I think I remember a thread that dealt with this problem.

 

[90Xjay]

If it is what I remember, and on an early to min 90s, then there is a tiny vacuum line that is prone to breaking. It is near the firewall on the passenger side.

let me know if this sounds right..

 

[Jeepr]

and there is a vacuum resovoir bottle behind the front bumper on the passenger side, it may be cracked.

 

[90Xjay]

excellent point

 

[mujaman]

thanks for all the info... i too suspected it might have something to do with a vacuum leak, but i wasn't sure.

i know about the vacuum canister thats up inside the bumper... and i will definitely check that. i had to remount it when i installed my ARB bumper, so maybe i messed something up (although that was years ago... i've had the problem for some time, its just gotten worse lately).

i will look for any sort of small broken vacuum lines along the passenger side firewall as well.

thanks again!

 

[Laph]

on my '99 wj i have a simular vacume prob with my ac, but what it does is if i have it on circulate cabin air sometime it will cut out and make it only do defrost vents. if i take the overdrive off while i'm going down the interstate, then engage it back it will start to work cause the rpms go up with over drive on then back down so it get the vacume to open the vent again, I have been to lazy for the most part to look for it but i know it's a vacume prob somewhere. Let me know what you find.

 

[90Xjay]

thanks for all the info... i too suspected it might have something to do with a vacuum leak, but i wasn't sure.

i know about the vacuum canister thats up inside the bumper... and i will definitely check that. i had to remount it when i installed my ARB bumper, so maybe i messed something up (although that was years ago... i've had the problem for some time, its just gotten worse lately).

i will look for any sort of small broken vacuum lines along the passenger side firewall as well.

thanks again!

Let us know how it goes.