Compressor working all the time?

What's the year, make, and model of your engine?

 

Look for air leaks first, especially in the brakes. Charge it up, chock the wheels, release the brakes, shut it off, and listen.

 

Listening for leaks is better with a length of hose. Use it like a stethoscope, one end in your ear and the other end searching for the hissing sound of the leak.

Get a spray bottle and fill it with water and a dash of dish washing detergent. Spray down connectors in your air system. Leaks will bubble.

About a year ago I had an air dryer replaced on a Freightliner Century Classic running a D60 (2007). The air dryer was inside the primary air tank, but they mounted a new air dryer in front of it. All was good for about a month. Then serious air leaks started to develop.

I took it back to the same shop to fix the air leaks under warranty. The problem was that mechanics aren't plumbers. Air lines are a plumbing problem. The first time they installed the new air dryer they clipped off the air lines and inserted them into the connections. That ALWAYS leaves a sharp nipple pointing up on the clipped end of the air line. That sharp nipple will cut into the O-ring, causing a leak. I instructed the mechanic to smooth the sharp nipples before inserting them into the new connectors. Problem solved.

 

OK you most likely got a Bendix AD-IS air dryer which is what I have on my trucks too.

I'm not thinking leaks, it seems to be something else.

The first thing is that the electrical wire going to the unit is not for the governor, it is for the heater in the unit.

The second thing is this is a governor issue. It is an AD-9 governor.

so it can be a couple things that could cause this

a - if you replaced the entire air dryer (which you don't have to) and did replace the governor, you may have a defective governor.

b - if you replaced the entire air dryer, you may have gotten the two lines from the compressor mixed up (not likely because I think there is one small line and one large line from the compressor, the large line is really for the supply but also has a turbo compensation scheme).

c - the port on the governor for the compressor unloading is on the wrong port - I've had this happen a few times when I would get non-bendix replacement governors.

d - there is a check valve behind the governor that is in the dryer, if this is defective, it will kick the compressor in and out a lot.

Hope that helps.

 

Ok well then all of that other stuff can help someone else.

However you have an eap air system which sucks, I also have that on three trucks and it is a pain in the butt.

It is nearly impossible to figure out what's going on because the abs/drive train module actually controls the system and it can be the module, one of the three sensors or the wiring harness and the only way to tell is to have it hooked to the computer at the dealer to pull the codes and have the module reset - volvos are a pia.

 

Did you use the merited toolbox software?