Freightliner DPF Cleaning

Posted by Sea-Anxiety6491@reddit | Truckers | View on Reddit | 20 comments

Got a freightliner (not one box) it will do a parked regen, but it won't do a highway regen. Keep getting low temp codes when trying to do a regen while rolling down the highway.

Am thinking of taking the DPFs off and giving them a gentle pressure wash.

Is this a bad idea?

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Ok_Application_2292@reddit

Egr valve stuck not allowing to close to build up heat to cook off had that happen on a 14l Detroit with just a DPF filter (no def system ) and also a MBE4000 engine same thing No def system

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Ok_Application_2292@reddit

I have also seen aborts due to fuel filter issues. Could not get fuel to get burn level up as well. Again all DPF system no DEf. 08-011 year models

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Sea-Anxiety6491@reddit (OP)

Thanks, Mines a 2017 DD15 (2 filter fuel, no DEF)

I just changed the fuel filters this weekend, so I will see how that goes. They did seem a bit dirtier than normal.

Weird thing is, I have 2 trucks, both exactly the same, and they both have starting doing it. I know some diesel standards for us have been relaxed due to shortages, not sure if that might have something to do with it.

It's a long process to try and diagnose, not like you can take it for a drive around the block to make it highway burn.

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hera_the_destroyer@reddit

How will that help with your low temp issue? Either learn how aftertreatment works, or pay for it to be done right. You will loose more money in down time “fixing” it yourself.

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Sea-Anxiety6491@reddit (OP)

I thought a reasonably full dpf caused exactly this issue?

Temp Sensors - they work fine while doing a parked regen (why would they not work when driving)

Pressure Sensors - they work fine wile doing a parked regen (why would the not work when driving)

EGR cooler is new

7th injector passes the 7th injector test on the software.

Truck starts the regen while driving from what I can tell, but fails after about 20mins.

Happy to hear your thoughts, what else could it be?

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hera_the_destroyer@reddit

Since you have the software, what are all of the temp sensors reading? If they do indicate a plugged dpf, I would still have it professionally cleaned. There are places where you can bring it to them and they will clean it same to next day.

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Sea-Anxiety6491@reddit (OP)

I don't have the software, but plugged it in at my mechanic the other day, only got the temps during a parked regen. I will have to head back and try to get the download of the failed rolling regen. Was in rush and needed to get back on the road.

DOC outlet Temp, and DPF outlet temp both got to about 540 degrees celcius

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hera_the_destroyer@reddit

I am guessing there is more going on still. If this is a unit from say 2011 to 2014, my hunch is that the harness for all of those sensors has some over heated wires. Hard to say. Either way, do not spray out the dpf, have it professionally cleaned.

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Sea-Anxiety6491@reddit (OP)

Hang on, you had a dig at me for "not knowing the process" but then you really haven't given a single answer.

Why would a bad electrical harness work perfectly fine when parked, but when rolling, they don't work? I have never seen an electrical harness act that way....

So now your agreeing I should have the dpf cleaned? Last time you implied that couldn't possibly cause a low temp reading.

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hera_the_destroyer@reddit

Your initial post left out a lot of detail. The main take away is, if you are going to pull the dpf, don’t wash it with a hose, have it professionally cleaned. I don’t think that is your issue though, but I am not there looking at it.

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Sea-Anxiety6491@reddit (OP)

Forgot, I took a pic

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amazingmaple@reddit

Hook it up to a computer and get the codes. Could be just a sensor

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Sea-Anxiety6491@reddit (OP)

Sensors work fine while parked, would they really not work ok while driving?

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amazingmaple@reddit

You need to see if it's throwing a code

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Sea-Anxiety6491@reddit (OP)

It does, I haven't got the exact code, but it was low temp, regen aborted.

I will have to try and get the exact code after Easter break.

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amazingmaple@reddit

Yes I have.

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fiddintotellya@reddit

Best effort would be run and ask for a copy of the log file when the problem happens.

This is one reason diagnostics are expensive. Paying for a tech w/laptop hooked up while recreating the issue. It will capture all parameters when problem happens.

Another thing to consider: are you really loading the engine during an active regen? Some applications don’t get enough ‘work’ to successfully complete an active regen. It takes a heavy load and a lugging strategy.

I would not try to clean the dpf. Without the proper equipment to soak and pressurize. Unlike most dpf cleaners which ‘bake’ the filter, Detroit recommends a liquid cleaning, which in our world is exchange.

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Sea-Anxiety6491@reddit (OP)

We are doing the same work we have done the last 5 years, never had an issue with it before, same truck, same work, same loads.