Service Air Suspension...Again!!! HUMTECH

[Easy Ed]

Hope it is not the air inlet filter that the services manual does not mention.

Post Link http://www.elcovaforums.com/forums/s...air+suspension

I think this may have been the problem. would have changed it if I knew it was stuck up and under the drivers rear fenderwell Restricted air flow to the compressor, caused it to heat up and shut down til the next start up and then all over again.
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[HUMTECH]

If the compressor runs for 20-30 seconds without a height change it will set a code and disable the air ride. If your positive you have no leaks it sounds like the compressor may be too weak to inflate the springs. As easy Ed said if the inlet filter is plugged this could also be the problem, no inlet air=no output from compressor. Check the filter, if its plugged remove it and see if it works. If thats not it try to raise the rear of the body a few inches with a jack under the receiver hitch and see if the bags start to inflate, if so the compressor is jus weak. If all that fails a new compressor is likely in your future, the new compressor will need to be upfitted with new air lines as well if you still have the older single stage unit. Make sure these are ordered with the new unit.

[14u2nv2]

Thanks to everyone for your replies...

Planohummer,

That's kinda what I thought it might be--a problem with the valve block/exhaust solenoid on the compressor assembly.

How long would it take to trigger an overtemp fault? The compressor stops in 20-30 seconds on it's own, but if I turn it on with the switch in the back of the truck (onboard air/hose) it stays on as long as I like. Wouldn't the compressor overheat and trigger the overtemp fault while using the switch/hose in the back?


Easy Ed,

I read your other post where you posted that photo of the filter and that was one of the first things I checked. My truck has a ceramic style filter and it looks OK.

How long did your compressor run before it shut down? Was your onboard air hose working and did the compressor stay on while you had the switch in the back turned on?


HUMTECH,

I had the driver side air line disconected from the air spring and the truck lowered all the way(to make the sensor think it needed to be raised)and no air was coming out of the air line(to air spring) while the compressor was running.

Is it possible that the new sensor is so far out of calibration, that it thinks the truck is too high(even when lowered all the way)?

Do you know the part# for the air lines if I convert from the old model to new model compressor?

By the way...Thanks for the tip you posted about rerouting the harness to the new version sensor. You saved me $150.


Thanks again,

John

[Easy Ed]

"My truck has a ceramic style filter and it looks OK" That is a bonus.

"How long did your compressor run before it shut down" Less than a minute, I think, been a while.

"Was your onboard air hose working and did the compressor stay on while you had the switch in the back turned on?" Nope

Good luck with yours, Ed

[HUMTECH]

If the compressor is running it is trying to inflate the bags so calibration is not an issue. Is there air going to the other line? if not i would say your compressor is hooped. I dont know the part numbers but any gm dealer should be able to find them, there should be a note in there catalogue for required parts when upfitting the dual stage compressor in place of the single stage unit

[14u2nv2]

I haven't checked the other (passenger side)line, but there is some pressure in the air spring, although that side isn't raising either. The driver's side air spring was completely empty before I removed it and had no pressure. I'll check the other(passenger side) line tomorrow.

Can you tell from the photo if this is the newer two-stage compressor or the older single stage...





Thanks again,

John

[Planohummer]

that's the original single stage.
the amount of pressure for lifting the truck is a whole lot more than what's at the rear aux port. This may be why the pump runs ok when it's not lifting the truck.
You really need to check the DTCs before you spend any money-make sure it's not just a height sensor recal issue or something similar. Any GM store can ck the codes for you, when you get them post them on the forum and we'll decipher.