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Discussion Starter · #1 ·
Hello,

We have a 2011 WK2. Just did the cam/lifter repair and while idling in the drive the front end lowers and then raises. Then the cycle repeats again as if it cannot make up its mind.

I purchased the appcar diagfca and will have the OBD2 connector tomorrow but wondering if there are some good threads on this issue. I searched quite a few but did not find a hit for this particular issue.

-Tom
 

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It sounds like there is an actual problem with the QL system on your vehicle and it needs to be diagnosed.
 

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Discussion Starter · #3 ·
Yeah. Ill have a better idea when appcar is connected but trying to get a running start in the issue. Could be the switch panel buttons perhaps. Hopefully I can see their status in the diag tool.
 

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Discussion Starter · #5 ·
Haven't touched anything yet but its something like that. Could be bad signals from the switches maybe.
I got the wrong OBD adapter for Appcar so waiting for another one. Then the Appcar learning curve starts!
 

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Discussion Starter · #7 ·
So I ponied up and bought Appcar DiagFCA and a OBDLinkLX. The first thing I discovered is main air tank is at 25lbs!
Since I have an argon tank and a standard low side AC quick connect fits the tank I filled it to 80psi which at least let me run the height check routine. I have a high pressure regulator coming and will do the air mass routine when it arrives.
The diag also displays the system pressures at all four corners, tank and pump so I can monitor for leaks.

A note on heights. the values displayed are the difference between wheel center and a specific chassis point hence the small values.
 

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The closed system uses Nitrogen...
 

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Discussion Starter · #9 ·
The closed system uses Nitrogen...
True but since Nitrogen and Argon have similar PV characteristics especially at the low pressures we are talking about the difference should be indistinguishable, other than the significantly higher cost of argon. Still cheaper than buying a whole new N2 tank though.
 

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Discussion Starter · #10 ·
It appears the system has a leak somewhere. After filling and cycling system last night airmass was 205. This morning before any leveling it was 168.
Question: 2011 GC. I want to check pressure readings on airbags overnight. I have to switch on ignition to do that.
My question is does the system attempt to manage pressures when car is off or when just ignition is switched on?
Im thinking no but wanted to see if someone can verify that.
Pressures this am:
LF 8.2
RF 8.2
LR 8.1
RR 7.1
TANK 7.8

I plan on checking this evening letting car sit all day.
I did check the front bag connections and all the connections at valve body. No leaks there.
I have yet to check the rear connections and get at the tank connection.
 

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I believe the car manages when the ignition is on..but I'm not 100% sure. I would just unplugged the battery overnight and measure each corner to see where the leaks coming from.. im sure you've already thought of doing that..This air suspension is something else. My compressor keeps turning on more often but cannot find a leak anywhere. Might be a failing compressor 🙄
 

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Discussion Starter · #12 ·
Yeah, I have a suspicion that an airbag may leak faster above some certain height.
What I want to do is fill each back to a know pressure then recheck. Sounds simple but I have not found exactly how to do that yet.
 

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I just wanted to reply here because it seems like a more relevant thread.

As far as finding a leak and determining if its in a line or at one of the o-rings:
Put your jeep in the highest suspensions level, then disable the air suspension. It's probably different on your 2011, but I'm sure you can google the procedure. If after a night, all the shocks have lost air, its probably a leak in your solenoid block or near the pump. (youtube "quadralift fix" OR "finding air suspension leaks").
Most of the leaks seem to come from o-rings but there are plenty of videos from many vehicles that show diagnosis and fixes for air suspension leaks.

If you find that after a night, only one shock has deflated, you can do something radical to isolate the one shock. I may have seen it here on jeepgarage, but someone removed the residual pressure valve and replaced it with a screw in schrader valve. (YOU HAVE TO MAKE SURE THE THREAD PITCH IS THE SAME). That allows you to inflate a single shock with an air pump and then check for leaks.

There's so many good tips on solving this problem here on Jeepgarage. Just spend the time searching and reading. You'll find the leak eventually. I'm betting it's just an o-ring somewhere that's lived it full life.
 

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Discussion Starter · #14 ·
I was wondering about that valve block. The actual connections seem ok but the block itself could have an issue.
Ill see if I can get it out of Shop mode so I can raise it.
 
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