Cummins ISX Air Compressor Problem

Usually carbon build up in the compressor head and the unloader mechanism sticks. A few taps with a hammer usually gets it going again.

 

Is that a Wabco?

 

Cummins has procedure for the air compressor valve unloader cleaning.
Air pressure should be drained to ZERO.
Disconnect both sides of compressor and air pressure governor tube.
Spray liberal amount of WD40 into air pressure governor .
Put some rug over compressor discharge opening .
Safety glasses is ON !!!!!!!!!!!!
Start engine and spray WD-40 into pumping compressor until carbon deposits are washed from the valve.

 

Sounds like the issue I had last year. In my case it didn't have to go all the way to zero. I'd start the truck in the morning and it wouldn't start building pressure till the truck ran for 10 or so minutes in high idle. After reading about the unloader valve carbon problem I tried tapping the compressor head with a hammer while doing my pretrip. Worked every time. Ended up replacing the compressor.

 

That worked for me as well a couple years back.

 

would replacing unloader valves with the unloader kit solve this problem?

 

seems like 40 dollar unloader valve kit would have solved your problem? I thought you only replace compressor if its pumping oil?

 

The compressor for an ISX doesn't really have the same unloader mechanism that Bendix Tuflow model has. You just replace the whole head unit on an ISX compressor.