2016 GMC Yukon air ride suspension problem

[smkybr74]

Hello. I am having an issue with the compressor motor coming on intermittently while driving and while stopped. I took the vehicle to a reliable mechanic and he can't find the issue. Here is what I know. I replaced the air shocks with Monroe MaxAir shocks. We smoke tested for leaks- no leaks. All of the air ride suspension components check out with proper volts on the scanning tool. There are no error messages showing up on my dash. It did not act up while in the shop- parked while running. He did not take on a test run. The compressor kicks on while driving and parked and then shuts off. It will kick on after a few minutes, run for a while and then shut off. This repeats. There is no load in the back. What is causing the compressor to kick on and off? Thank you.

 

[wjburken]

I would double check for leaks on the air bladders with some soapy water. Also check all the air line fittings.

How old is the compressor? It may have a bad relief valve that is letting air out slowly causing the system to bleed down and make the comp ray kick back in again.

 

[smkybr74]

Thanks. All of the lines were smoke tested and the shocks are brand new. I am suspecting the compressor. The relief valve makes sense. Thanks for your help.

 

[smkybr74]

I would double check for leaks on the air bladders with some soapy water. Also check all the air line fittings.

How old is the compressor? It may have a bad relief valve that is letting air out slowly causing the system to bleed down and make the comp ray kick back in again.

Thanks. All of the lines were smoke tested and the shocks are brand new. I am suspecting the compressor. The relief valve makes sense. The compressor is original. Also, with the Monroe Max Air shocks there are no visible bladders like the original shocks had. I assumed they are inside the shock? Thanks for your suggestion.

 

[Joseph Garcia]

Test it with a soapy mixture in a spray bottle, as @wjburken suggested, as it is a more positive indicator than a smoke test.

Also saw this on the Summit Racing web site:

Monroe Max Air Shock Absorbers MA834​

Summit Racing
https://www.summitracing.com › parts › mon-ma834



Does not fit models with the Z95 magnetic ride control.

I don't know if this was the specific shock model that you purchased.

 

[wjburken]

Thanks. All of the lines were smoke tested and the shocks are brand new. I am suspecting the compressor. The relief valve makes sense. The compressor is original. Also, with the Monroe Max Air shocks there are no visible bladders like the original shocks had. I assumed they are inside the shock? Thanks for your suggestion.

If the compressor is original, especially if you live any where that gets snow and they salt the roads.

You are the first person I have heard of that tested a compressed air system with smoke so that’s a new one for me. In my 25+ year career designing equipment and working with pneumatics, I’ve been using soapy water to find leaks. How do you get the smoke into the system under pressure?

 

[Doubeleive]

as noted the pumps can leak and just go bad period, happened to me twice. both Arnott pumps, replaced with a dorman and no issue's since
first one had electronic issue it would inflate maybe 12 psi or 110psi or anything in between completely random
2nd one had a leaking relief valve, found with soap & water...... bubbles,,,,,

 

[smkybr74]

as noted the pumps can leak and just go bad period, happened to me twice. both Arnott pumps, replaced with a dorman and no issue's since
first one had electronic issue it would inflate maybe 12 psi or 110psi or anything in between completely random
2nd one had a leaking relief valve, found with soap & water...... bubbles,,,,,

Thanks everyone. I should have also noted I myself tested the lines and new shocks 4 times and found no leaks using soapy water. I am not sure how the mechanic tested with smoke. He told me he did this. This shop specializes in air ride systems. I took him at his word. He showed me the scanner and ran through everything showing no issues. I pulled the air line going to the passenger shock and air came out and I could feel and hear air coming out of the hose while the compressor was running. I tried this on the driver side and only heard very little if any air come out of the shock and could not feel or hear any air come out of the air line. Is it possible there is an issue with the compressor only pushing air out of the passenger line and not the driver side? This deal is very frustrating. I'm thinking of just replacing parts as I go ,beginning with the compressor. Everyone told me to let the scanner tell me but the scanner shows everything is perfect. I'm at a loss. Thank you all very much for the help. Please keep your suggestions coming. Do any of you live close to St. Louis?

 

[smkybr74]

Test it with a soapy mixture in a spray bottle, as @wjburken suggested, as it is a more positive indicator than a smoke test.

Also saw this on the Summit Racing web site:

Monroe Max Air Shock Absorbers MA834​

View attachment 422808
Summit Racing
https://www.summitracing.com › parts › mon-ma834



Does not fit models with the Z95 magnetic ride control.

I don't know if this was the specific shock model that you purchased.

Thanks but I don't have magnetic ride control. There are no electric wires coming off the top of the rear air shocks.

 

[Doubeleive]

Thanks everyone. I should have also noted I myself tested the lines and new shocks 4 times and found no leaks using soapy water. I am not sure how the mechanic tested with smoke. He told me he did this. This shop specializes in air ride systems. I took him at his word. He showed me the scanner and ran through everything showing no issues. I pulled the air line going to the passenger shock and air came out and I could feel and hear air coming out of the hose while the compressor was running. I tried this on the driver side and only heard very little if any air come out of the shock and could not feel or hear any air come out of the air line. Is it possible there is an issue with the compressor only pushing air out of the passenger line and not the driver side? This deal is very frustrating. I'm thinking of just replacing parts as I go ,beginning with the compressor. Everyone told me to let the scanner tell me but the scanner shows everything is perfect. I'm at a loss. Thank you all very much for the help. Please keep your suggestions coming. Do any of you live close to St. Louis?

the air line is a T so air pressure is the same at any position, it does not differentiate between left/right

so what I would do is check the air presure either after it has sat overnight (before you start it up) and/or after a drive before you have cycled the key
the system should hold air for days or even weeks or longer just sitting parked *without the pump having been ran
if there is no air pressure or not much in the above scenario's then you know you have a leak somewhere.......
normal psi resting is around 20-23psi, maybe slightly less if the relief valve has let a tiny bit out after shutting it off
you can sort-of judge that by cycling the key so the pump runs, then after go right away and pull the line off you will have a pop-hiss
if you pull the line off after it sat overnight before starting it then it should have the same pop-hiss feel/sound if there is no leaks, since you stated there are no external bladders to "feel"

 

[smkybr74]

Test it with a soapy mixture in a spray bottle, as @wjburken suggested, as it is a more positive indicator than a smoke test.

Also saw this on the Summit Racing web site:

Monroe Max Air Shock Absorbers MA834​

View attachment 422808
Summit Racing
https://www.summitracing.com › parts › mon-ma834



Does not fit models with the Z95 magnetic ride control.

I don't know if this was the specific shock model that you purchased.

Yes. These are what I have on there. I’ve given up and just let the compressor run when it wants to. I am disappointed I can’t figure it out. I’m still at a complete loss. Thanks.