THE ADVENTURES CONTINUE - DFO gets a truck and hops on Schneider's IC Choice Program

Well after some blood, sweat, and actually pretty liberal usage of the "f-word" the DPF is out.

On the downpipe behind the turbo there was just one clamp to remove. I think there 3 sensors that had to be disconnected. Behind the DPF was where things were a pain. Rusted exhaust u-clamps and band clamps broke off and I couldn't manage to free the pipe from the DPF that runs up towards the flex pipe at the stack without cutting it so I will have to replace the flex pipe and those clamps as well.

Honestly, for the time being I am really just considering routing the exhaust straight back behind the cab under the framerails like many of the company Cascadias are set up. I'll just remove the stack and associated brackets and hardware and set them to the side in case I need to put them back on at some point. Then next time I am home for a significant period of time I can set it back up if I choose to do so... don't really care about where the exhaust dumps out as long as its legal. I'd almost like to get a nice polished chrome tip and dump it out between the fairing and the APU, would look pretty cool. I'd just have to be careful not to regen next to anything LOL.

After I finally cut the flex pipe I was able to remove the rear section of exhaust pipe and then work it side to side between the frame rail and the driveshaft until it finally loosened up enough to pull it free from the rear of the DPF.

Then I put my trans jack under the DPF and strapped it on for the ride out, and then it was just a matter of removing the straps that secure the DPF to the frame rail which was just 4 3/4" bolts that lucky came out pretty easy.

Then I was able to work the DPF out through the opening between the APU and the fairings on the side of the truck.

Gonna go ahead and take the DPF down to Cummins and let them do their work. Hopefully by tomorrow evening I can get it back. While I'm down there I'll see if I can get any tips or tricks for removing/cleaning the doser injector. I'd like to not have to drain the coolant if I don't have to.

 

So, yesterday I got the DPF assembly back from Cummins and got it reinstalled in the truck. This was a bit of a pain, but its mainly just the gravel driveway to blame. Once this truck is paid off I'll be saving to build a shop, LOL. I purchased new flex pipe and clamps from Freightliner and hooked the exhaust stack back up.

Today I removed the doser injector. It appeared to have been removed before as it had newer looking bolts on it. Judging by the paint sprayed on the wiring harness I think its safe to say that that was the original doser and it was time to replace it, regardless of whether someone had removed it to "clean" it or not. This was tight, especially because I did not want to remove the elbow behind the exhaust housing on the turbocharger as that would require a fair bit more work removing rusty exhaust clamps.

I did have to drain the coolant to do this as the doser has coolant lines connected below and above it. The radiator drain valve on this Cascadia sits very low, but you can attach a tube to it so I bought some hose and 3 5 gallon buckets from Lowes and was able to drain it that way without much of a mess at all. In fact I made more of a mess putting all the coolant back in, lol.

You can see in the pictures I removed the doser injector with the coolant lines removed at the block side instead of the injector body itself. They were very tight and rusty on the injector itself and it required putting the injector in a vice in order to break them loose from the body. The new doser doesn't come with the adapters so you have to remove those from the old one as well.

You can see the old and new designs, the old one has a hole in the tip where the fuel is sprayed out. Its very easy to clog up with soot and from what I've read and from talking with the techs at Cummins, cleaning it is not always effective and it needs to be replaced. The new design almost looks like a pop-top sprinkler design. No idea if that is how it actually works, just my guess.

Putting it back in was a pain in the ### as well, especially since the new doser is shorter and the braided fuel line that connects to the back of it did NOT want to go on at a different angle. But, its all hooked up and we're in business.

I filled the coolant back up, started the engine and topped it off until all the coolant was back in. There were a lot of exhaust leaks at the band clamps, but they went away after taking the truck for a drive and they reseated themselves.

Tomorrow I'll take the truck down to Cummins again and they'll hook up their computer and reset the ECM's memory of the DPF being clogged up (it remembers how much pressure builds up in the DPF over time, and if it suddenly drops low (from cleaning) it panics thinking that there is a serious leak, such as a hole being knocked in the DPF.

So, hopefully this will solve my MPG problems. It may or may not, but this job needed to be done anyway at this mileage. If the mileage is still low there are a couple other sensors I can check out. But, as long as I keep the doser in good shape so it can do its job and keep the DPF clean, we should be good to go for a long time now.

If everything checks out at Cummins I'll either leave out tomorrow or Saturday, just depends on which day has better looking loads lined up for me. I'll probably try to get back for a day for Thanksgiving, but if I don't I'm not too worried.