Air Compressor on Cascadia running continuously

could be the govenor or the unloader valve, govenor is usually cheaper and easier to replace.

 

here is a service bulletin for that problem.

 

sounds like it maybe a stuck unloader. i believe we have replaced 2 or 3 compressors on that model engine.

 

Loose gov or major air leak? That would be why the compressor would be continuous duty. That's the spitter valve on the dryer you hear right? The high pressure safety valve on the tank should be 150 psi.

I have a fix when you guys park next to me at night. Loosen the unloader line, then I sleep in peace.

 

I just worked on a truck last night with a DD15 in it. The air was building to about 140 and I could hear air purging from what sounds like something near the back side of the engine. I dont know if there is a compressor back there or a valve.. But I saw a line moving every time it purged. It was a 2012 engine.

Anyhow.. having replaced the governor, and adjusting it, and putting a new air dryer filter on the problem was not resolved. The truck was building air normally it seemed.. but just sounds like a high pressure pop off. It would drop the pressure about 10psi and build back up and do it again. I wonder if this is what the TSB is for.... I wish I knew more about the newer trucks. This stuff is getting too advanced to try to take care of without any form of information. Im used to seeing a compressor on the front of the engine, with a line to the governor, and a line to the air dryer, then to the tanks. This integrated governor on the dryer housing with no lines and valved compressors you cant even see with all the emissions is difficult....

 

To test the governor and the unloaders, you need a fitting to be able to connect it to shop air, build the system untill the governor unloads then feel if the air is leaking past the intake the unloaders are leaking, then soap test the air Governor and air dryer unload er for leaks.
You do not buy parts you test and confirm.

 

I am fully aware of how to test... However as I stated.. It purged in cycles.. it did not leak. The unloader valves were working correctly in the sense that they were not leaking. I dont throw parts at anything if I can help it. I have a GOOD KNOWN governor I use for testing... I didnt just throw on the part against the customers will and expect him to pay for it.

From talking with another guy, he told me the DD15's have some sort of regen mode and they have a longer purge cycle and lose air pressure.. but its normal. I am going to check and confirm today at Detroit Diesel.

 

Hi there

I know it's been a while but did you find what the problem was?
I'm having the same identical problem but I noticed a leak at the unloader valve when the eng is running, but it actually stops as soon as you shut eng off, and the Primary tank only drops to about a 100 psi.

Thanks