2012 Hino 338 doesn’auto regen

sawslider

New Recruit
Owner/Operator
I just bought a 2012 Hino 338 and it came with DPF problems. It won’t do automatic regeneration. I changed the DPF filter and DEF pump with the injector. But still doesn’t do automatic regeneration. Any body that can give me a clue?
 

greasytshirt

Moderator
Staff member
Mechanic
I just bought a 2012 Hino 338 and it came with DPF problems. It won’t do automatic regeneration. I changed the DPF filter and DEF pump with the injector. But still doesn’t do automatic regeneration. Any body that can give me a clue?
The def pump and injector have nothing at all to do with regens.

This truck has a burner for DPF heating, rather than using post injection. Think of it as a large, somewhat temperamental reddi-heater. They need regular maintenance. You often need dealer software to decipher that is wrong. A generic HD scan tool will not communicate with the burner control unit.

If it's been about 150k miles without any burner maintenance, then you need to do it now. Clean off the ignitors, replace them if they're worn out. Replace the burner nozzle. Replace the flame temp sensor. Take the big braided line off of the front of the burner, and clean out the fitting on the face of the burner. This gets clogged.

There are a million other reasons it won't regen, but these are common. If the DPR graph is at ten bars, it has to go to a dealer anyway.

If the burner is loaded up with soot, the engine's fuel injectors are likely in need of replacement. Have them evaluated. Get the valves adjusted if you put injectors in it.

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sawslider

New Recruit
Owner/Operator
Yes, it does manual regen. In fact it does ask for manual regen every 100 miles. Sometimes when I stop and put the truck in neutral it show in the screen auto regen, but a soon I put the truck on gear it Stop the regen.
 

sawslider

New Recruit
Owner/Operator
Yes, it does manual regen. In fact it does ask for manual regen every 100 miles. Sometimes when I stop and put the truck in neutral it show in the screen auto regen, but a soon I put the truck on gear it Stop the regen.
 

greasytshirt

Moderator
Staff member
Mechanic
Yes, it does manual regen. In fact it does ask for manual regen every 100 miles. Sometimes when I stop and put the truck in neutral it show in the screen auto regen, but a soon I put the truck on gear it Stop the regen.
This part is normal. If you were to stop the truck and put it in park, it will tell you that an auto regen is in process. If you were to then press the regen button, it will finish by doing a manual regen.

Does it ever take a ridiculous amount of time to finish a manual regen, like maybe 45 minutes? If so, it's suffering from misfire, which usually clears up when those maintenance items I mentioned earlier are replaced.

You still might need a professional diagnosis, and finding a shop with a mechanic that actually understands how the burner works may be a bit of a hassle.
 
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sawslider

New Recruit
Owner/Operator
I did clean the items that you mentioned before and I noticed a ignitor needs to be replaced. I cleaned them any ways and it started the automatic regeneration but it stopped after 20 min. I will order those parts ASAP. Thank you so much for you help.


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greasytshirt

Moderator
Staff member
Mechanic
I did clean the items that you mentioned before and I noticed a ignitor needs to be replaced. I cleaned them any ways and it started the automatic regeneration but it stopped after 20 min. I will order those parts ASAP. Thank you so much for you help.


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Another thing when poking around in there: don't wipe off the face of the burner nozzle. Invariably, carbon gets mashed into the tiny orifices and makes it worse. Ignore face deposits, just spray brake cleaner through it.

You'll be replacing it this time around, but in 75k you'll want to try to clean it with brake cleaner. This is what Hino suggests, but I've had limited luck trying to clean them, and I've tried a dozen methods.

When tightening the tiny braided line, do not allow the line to twist and kink or it will immediately be destroyed. Use a backing wrench and do not over tighten it. It's easy to over tighten.

If you do these steps and it still won't burn, you need an actual diagnosis.

There's a part of the system called the atomizer. It does fuel and air mixing. It often develops faults with internal valves. Diagnosing this without appropriate software is basically impossible.

The burner mantle occasionally breaks.

The Combustion Air Valve occasionally sticks shut.


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sawslider

New Recruit
Owner/Operator
I replaced the two igniters the nozzle and the flame temp sensor today. The manual regeneration took 17 min but still the automatic regeneration stops after 3 min. I will take it to the dealer to get a diagnostic. Thanks you for you help. :)


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sawslider

New Recruit
Owner/Operator
After a manual regeneration. I drove for 75 miles and the DPF when up 3 bars. When I got to Stop the orange warning DPF regeneration light pop up. I stop the truck and it was @ 1000 RPM after 4 minutes it Stoped the auto regen and the warning went away.the RPM came down But the DPR still showed 3 bars.
 

greasytshirt

Moderator
Staff member
Mechanic
After a manual regeneration. I drove for 75 miles and the DPF when up 3 bars. When I got to Stop the orange warning DPF regeneration light pop up. I stop the truck and it was @ 1000 RPM after 4 minutes it Stoped the auto regen and the warning went away.the RPM came down But the DPR still showed 3 bars.

What it's doing at this moment sometimes confuses people. When it goes to three bars it starts an auto regen, like you said. When you stop moving, this warning pops up. Basically what it means is if you're gonna park, be careful because the exhaust it hotter than hell and will light stuff on fire. If you continue driving, this warning goes away and the auto regen continues. If you are ready to park and you want it to fining doing the regen, press the button. It will not successfully regen while stationary unless the button is pushed.

In other words, it may not have an actual problem at this point.
 
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