Help me decifer this new to me Denali's autoride

[NateDiggity]

Im trying to get this system working correctly, but not sure I even know what that really means lol

I had a service suspension DIC and had the codes pulled. One was the exhaust valve that usually means a corroded wire. Found it, and replaced/temporary fixed it last night around 11pm (Had to be up by 4:30 not real thrilled)

Anyway, the compressor now fires up and runs, but didnt have time to do much testing. I did however need to verify the trailer brake controller worked since my cruise/brake switch is bad. They didnt, so thats another project.

BUT, I backed the rig under the trailer, went, had a beer, then lowered the trailer onto the hitch ball with the vehicle off. I started the yukon, got all excited when the compressor kicked on, ran for a bit, 30 seconds maybe? but never seem to actually lift or level the truck. Thats not normal correct? Usually the compressor has enough balls to pump enough PSI to level the yukon even under heavy loads? (Its actually a pretty small RV trailer considering).


What really throws me is that the rear shocks and front struts seemed to be replacements, they are label BWI though, which seem to just be an OEM supplier. With that said, they still have an air line running to them so they are non-air ride replacements. The rear coils are also replacement and with the shock still being air-ride why would they replace the coils? I was under the impression the coils were only replaced when going to non auto ride setup?


Also, something else interesting, everything I read said this body style has the compressore behind the passenger wheel, while the older body style was behind drivers rear wheel. Mine was behind the drivers rear wheel, is this an early 07 model year thing?

 

[NateDiggity]

The more I think about it I'm kind of convinced the shocks are aftermarket non air ride. That would explain why it won't air up even though the compressor is on. That would also explain the aftermarket coils, or at least not in stock. The only part that really throws me is the airlines still running to the shocks, could this be the autoride? Just not the load leveling?

 

[#1taho]

Pics will help

 

[02Lightning]

BWI are stock shocks, that is what's on my Denali and on my Cadillac CTS-V. If I get a bunch of people in the car it will kick on for 30 sec. then kick off. I’ve never really had mine squatting to see if would level out, so I’m not sure on that. Mine is a 2008 and I was just under it changing the rear diff fluid, I remember looking at the compressor but can’t remember what side it was on, I’ll have to look tonight.

 

[PatDTN]

Listening in on this. Was just under my '09 Tahoe LTZ today. It was off but I thought the system should have kept minimal pressure in the air shocks. They were clearly empty. At least in the past air shocks could be damaged running empty.

 

[Christoph559]

Listening in on this. Was just under my '09 Tahoe LTZ today. It was off but I thought the system should have kept minimal pressure in the air shocks. They were clearly empty. At least in the past air shocks could be damaged running empty.

Yes they should retain air in them

The more I think about it I'm kind of convinced the shocks are aftermarket non air ride. That would explain why it won't air up even though the compressor is on. That would also explain the aftermarket coils, or at least not in stock. The only part that really throws me is the airlines still running to the shocks, could this be the autoride? Just not the load leveling?

Do yours look like mine with the rubber bladder?

 

[Rocket Man]

Make sure the air lines actually hook up to the shocks and check for air leaks where they connect using soapy water. Also look for blown out air bladders on the rear shocks and listen for air leaking;; fronts aren't air shocks, they only have electronic damping.

 

[STORMIN08]

I would be checking for leaks...possibly even some internal blockage.

My 13, airs up and adjusts even from my body weight (250lbs.) sitting in the rear

 

[02Lightning]

Also, something else interesting, everything I read said this body style has the compressore behind the passenger wheel, while the older body style was behind drivers rear wheel. Mine was behind the drivers rear wheel, is this an early 07 model year thing?

Mine is behind the rear drivers wheel.

 

[PatDTN]

In response to Christoph559's post and the fact that mine is not holding air I looked for a description of the system and found this

http://www.underhoodservice.com/servicing-gm-autoride-rear-air-suspension/

With this in mind I'm going to see what I have now.

 

[Rocket Man]

In response to Christoph559's post and the fact that mine is not holding air I looked for a description of the system and found this

http://www.underhoodservice.com/servicing-gm-autoride-rear-air-suspension/

With this in mind I'm going to see what I have now.

Are you sure yours isn't holding air or maybe your compressor isn't turning on at all? It's easy to check for air pressure- first, start the engine and go listen back by the rear for the sound of the compressor turning on and running for a minute or so. (This will only happen if it's been sitting for overnight or similar amount of time)You should notice the rear lift up a bit. Then shut off the engine and pull the metal clip on an air line at one of the shocks and air should release and the suspension should settle a bit. How are you determining that you have no air in your system ? It's hard to tell by looking at your shocks.

 

[PatDTN]

Are you sure yours isn't holding air or maybe your compressor isn't turning on at all? It's easy to check for air pressure- first, start the engine and go listen back by the rear for the sound of the compressor turning on and running for a minute or so. (This will only happen if it's been sitting for overnight or similar amount of time)You should notice the rear lift up a bit. Then shut off the engine and pull the metal clip on an air line at one of the shocks and air should release and the suspension should settle a bit. How are you determining that you have no air in your system ? It's hard to tell by looking at your shocks.

My air shocks look like a dude who's been in cold water too long. Plus the bags are crunchy they're so dried out.

I started in to work on this today but got sidetracked moving stuff around in my garage. So far I've put the rear up on jackstands and crawled around a little under it. I laid eyes on the linkage onto the rear suspension to detect ride height and the compressor behind the left rear wheel.

I need to get the front up now so there's room; I want to rotate the crap Wranglers off the front and go with whatever is on the back to see if I can reduce the tramlining a bit.

 

[NateDiggity]

So I got mine pumping up, and that is working, but now I seem to have a leak, the compressor will go out if I keep driving it like this, it seems to kick on every few minutes. Odd thing is after I drive it for awhile it doesnt anymore, but its in a protection mode...

I climbed under there with a spray bottle of soapy water and soaked my lines at the comp, the tee and at both shocks, as well as the shocks and didnt find anything. After doing some searching and finding another thread I was told to paint on the soapy water with a paint brush and then fire the truck up to check for leaks... not sure how this differs greatly from my plan but its worth a shot. I was also told to soak the compressor itself as it will sometimes have a leak between the compressor and dryer, I did not do this and I will check that over closely... I would have thought with the compressor kicking on that much that I would have heard a leak but never could.

Also how loud is your compressor? Mine can be heard from 30' away with the motor running, is this substantially louder than normal?

 

[Rocket Man]

So I got mine pumping up, and that is working, but now I seem to have a leak, the compressor will go out if I keep driving it like this, it seems to kick on every few minutes. Odd thing is after I drive it for awhile it doesnt anymore, but its in a protection mode...

I climbed under there with a spray bottle of soapy water and soaked my lines at the comp, the tee and at both shocks, as well as the shocks and didnt find anything. After doing some searching and finding another thread I was told to paint on the soapy water with a paint brush and then fire the truck up to check for leaks... not sure how this differs greatly from my plan but its worth a shot. I was also told to soak the compressor itself as it will sometimes have a leak between the compressor and dryer, I did not do this and I will check that over closely... I would have thought with the compressor kicking on that much that I would have heard a leak but never could.

Also how loud is your compressor? Mine can be heard from 30' away with the motor running, is this substantially louder than normal?

I need to stand close to my truck to hear mine but it's a new Arnott replacement; unsure how loud an OEM one is. As far as checking for leaks- if a bladder on your shock is blown out you won't hear a leak I doubt since there won't be any pressure built up due to a large hole. These systems deal with a minimum amount of air- the air lines are tiny on the inside. They do have a significant amount of pressure I believe. It could also be that your compressor isn't actually pumping any air. Take a line off at the tee or a shock and get the compressor to turn on (if it doesn't automatically) by disconnecting a ride height sensor and simulating a heavy load by moving the rod up (like the suspension is moving up). Then see if any air is coming out of the line. You need to see if there's air actually being pumped into the system before assuming it's leaking out.

 

[PatDTN]

I'm trying to sort out the ALC on my 09 LTZ. Today I popped off one of the wheel height sensors and shoved it up high enough to think the tire was going to come through the roof soon. Nothing happened.

I decided to skip ahead to the compressor. I unbolted the entire compressor setup with the 3 13mm nuts. Too bad I didn't realize those don't have to come all the way off because the frame is keyhole notched for them. It was looking pretty cruddy in there.

Reading around on line I saw where someone just applied 12 volts across the red and black terminals in the connector and their pump spun. I tried that and got arcing and sparking like a dead short so I quit that. My best guess is the compressor is burned up. Oddly the 40 amp fuse and the little 30 amp near it under the hood are both good.

Before I spring for the complete Arnott compressor setup - mine was so rusted I couldn't disassemble the box - what should I test.

I did use my garage air compressor and blow up the rear shocks through the line from the compressor. I could just get my pinkie in there to block the line and it seemed to hold air. It raised the vehicle a couple of inches. Obviously holding my pinkie in there I couldn't run around and spray or brush soapy water on things but it seemed stable and I didn't hear air leaking.

I'm aware of the control box under the dash and the sensors on all 4 wheels. What else can go wrong? How can I test for that?

Thanks!

 

[Rocket Man]

One other common problem, and it happened to mine, is the compressor ground. The lug where it attached to the frame was rusted and it wasn't making contact so my new compressor wouldn't turn on. Mine is a different body style (2002), but I have a fuse labeled RTD (real time damping) in the underhood fuse block that operates the compressor. You may not have that but if you do, check it. Since you checked your compressor by applying 12v and ground, it must be bad so I don't see any issue with buying a new one.

 

[02Lightning]

I would get the Dorman compressor, comes with new bracket and you don't have to splice wire.

 

[PatDTN]

I ordered the Arnott complete compressor with bracket from Shockwarehouse for $209.00 with free shipping. With luck I'll have it by Friday. It's a direct drop in and comes with two wiring harnesses for some difference.

 

[PatDTN]

Sorry for hogging this thred. Got my complete Arnott compressor assembly today. I took the old one out when I realized it was shot. Remembering how accessible that is I grabbed a 13mm deepwell socket and slid under on a mat with the new compressor. It was completely installed in 15 minutes and pumped up and stopped when I started the Tahoe. I'll see if my system holds air after having been run for doG knows how long with no air in the shocks.

Looking like $209.00 well spent.

 

[Rocket Man]

Sorry for hogging this thred. Got my complete Arnott compressor assembly today. I took the old one out when I realized it was shot. Remembering how accessible that is I grabbed a 13mm deepwell socket and slid under on a mat with the new compressor. It was completely installed in 15 minutes and pumped up and stopped when I started the Tahoe. I'll see if my system holds air after having been run for doG knows how long with no air in the shocks.

Looking like $209.00 well spent.

Awesome to hear. Hoping you're all set. And no need to apologize.