Cummings isx catalyst dosing unit

If it were me I'd get it looked at now, putting it off could leave you with a tow bill if that thing desides to derate or shut down completely. Sounds like it could be the doser valve going bad.

 

What fault it it? They sell a kit, which is just some gaskets and bolts, to service the dosing unit. They clog up and should be pulled off once in a while and cleaned out. We did a 2012 last week that was not having any problems, just routine maintenance, but when I got it off, I was amazed that it was even working. The hole is about 3/8", but was clogged down to less than 1/16". It took a pick to get the dried DEF off and I use a brass wire brush to clean out the doser head.

After seeing that, we changed that scedule to an annual rather than bi-annual. There is also a DEF filter that is easy to change.

 

What is a Cummings? That's your first problem, misidentifying your engine.

 

The DEF doser? It's not a difficult thing to service, but it is sort of a pain in the ###, unless you have a short enough sleeper that you could lay on the catwalk and get to it. It'll be similar to the dosing injector on the engine, except the insulator will be smaller, and you'll probably need a small chisel to get it out of there, and make sure you clean it out well. Two bolts, a gasket, and an insulator... one thing Cummins definitely got right was these dosing injectors.

 

You must have a different setup than our 389's. On ours, you just slide under the right side step and it's right there out in the open. 2 V-bands clamps will take the whole pipe off so you can work on it on the bench.

 

We must. On our T660s and T800s (haven't serviced one on a 680, Volvo, or PornStar yet), it's located above and slightly left of the driveshaft.

 

Same for the paccar engine since it's also the Cummins emissions on it. My smartnav says I got that problem to. The spn3361 but when the shop plugs in Davies dissent show no codes for it.