Greasytshirt,
I am having a problem with 2008 Hino 268A with 180,000 miles. Got the DPF filter cleaned about 500 miles ago. Today the manual regen light came on 3 times. There are no bars on the display and it asked to run the DPF again. Any thoughts as to what might be going on. Not sure if the driver today had the exhaust brake on all day and was interrupting and auto regens. I am very concerned that this could be expensive. Hoping it is something as simple as a sensor replacement.
Thanks for you help
Hi there,
Edit: Is the check engine light on? Check for inactive codes in the dash. Push the mode button until system check comes up. Press up to select. Press up and hold to access inactive codes. press up to cycle through them. Post them here.
Edit #2:
Today the manual regen light came on 3 times.
You mean it started alarming, and the DPF button light started flashing? If not, where on the dash was this light?
Are you sure it was not the exhaust brake light? They are very similar.
I answer questions like this one like I'm addressing an audience.
2008-2010 trucks have a DOC and DPF, no DEF to worry about.
The DPF heating is accomplished by post injection and help from the exhaust brake.
EGR is shut off. The intake throttle valve (ITV) opens all the way up. The VNT moves to limit turbo boost (you want excess fuel so it burns hot).
This is what happens if everything is working correctly. Engine runs at 980 rpm, the exhaust brake closes, extra fuel is injected (to both overcome the restriction of the exhaust brake, and it's injected late so it's burning outside of the engine). The exhaust starts heating up. At around 400F, the DOC (diesel oxidation catalyst) lights off and the temperature quicky eclipses 1000 degrees. The inlet temp settles out at around 1030F, and the ecu maintains that temp via changing injection quantity. The outlet temp starts rising. Once it gets up to around 850 or so, the soot starts burning off. It'll maintain that temp for around 10 minutes, maybe more if the differential pressure across the DPF is high. Then it stops post injection and opens the exhaust brake. Voila!
An unsuccessful regen means one of two things: It didn't get up to temp, or the temp is comparable to the surface of the sun.
If the DPF becomes a fusion reactor, the first thing to check is the ITV. Take the CAC outlet hose off and look inside the thing that looks like a throttle body. There's a throttle plate in there. Grab it and wiggle. Is there any side to side play? Is the plate loose? If so, try to hit a mailbox with it on your way to the dealership. The ITV should also have three holes drilled into the bottom of the throttle plate. They are going to look like they are hand drilled (because they are). If not, take the ITV off of the engine and find a sharp 3mm (1/8th is close enough) drill bit. Scribe a circular line 8mm above the BOTTOM edge of the plate. Put a punch mark in the 6 o'clock position. 20 degrees away, on either side, along the line you scribed, put another two punch marks. Like the bottom of a peace symbol. I hope that makes sense. Anyway, you're gonna drill these three holes. The brass plate is pretty hard, and your bit is gonna drift a bit, but luckily this doesn't have to be perfect. Deburr the holes and clean everything when you're done. Do this to the new ITV if you had to replace your old one.
The reason you are doing this is to help the motor that turns the plate, in case the plate gets stuck in place from all the mung and crap that builds up behind it. You are just creating enough of an air leak to allow the plate to open easier, but not too much to disrupt EGR flow with the plate partially closed. If the truck sounds like a Chevy 350 with the distributor advanced too far while it's starting up, it'll fix that, too.
Well, unless your injectors need to be replaced. Which is the #1 reason for excess soot and frequent regens. Well, if the ITV has not been modified, that should be done first. Then you can get around to blaming the injectors.
But first, especially if you're pretty sure the injectors are kind of crappy already, you need to go to the dealer and get the exhaust brake reset. As injectors degrade and start to leak, the ecu will trim back injection quantity. The exhaust brake setting will have stayed the same, and that means too much fuel will be injected with the exhaust brake on. Having this adjusted correctly is crucial.
Now, before you spend a dime, call your local dealer and give him the VIN, and see if the A8440/A8510 recalls pertain to your truck. If so, take it in. They'll inspect the DPF and replace it if it's messed up, no questions asked. Then they will adjust the exhaust brake. The computer will get reflashed at the same time. You can pay them to inspect, replace, and/or modify the ITV at the same time (ITV not part of the recall), or you can do it yourself.
If you're lucky, the temp sensor in the middle of the DPF will break off (they often do), and you'll get a new one of those for free.
Other causes of excess soot in the DPF include butt turrible air filters, engines that are massively overfilled with oil, and turbos barfing oil into the CAC (they all pass a little oil anyway, but if it's dripping out, consider replacing the turbo).
Yet another thing that can cause frequent regens is broken wires on the harness side of the DPF temp sensors (especially the upstream one). Vibration in this area sometimes causes an internal break in the harness. You can load test the circuit with a headlight bulb and a 12v source, but you'll need a wiring diagram to identify which pins to mess with on the ecu connectors. If you don't know what I'm talking about, ignore the suggestion about load testing. Really avoid sticking anything with an energized power probe. That can go bad in an instant.
If the DPR switch is blinking with no bars on the dash, I think that's an indication that the truck was shut off while it was doing a manual regen. Not sure. That's a bit unusual.
There's also a thing called white smoke mode which engages when it's cold out and the truck has been idling for a while. It'll rev itself up a little, turn on the exhaust brake by itself, and the brake will not turn off until you start driving. This one messes with people's heads.
TL;DR: Inspect ITV, modify if necessary, call dealer and see if your truck is part of A8440/A8510 recalls, don't overfill with oil, change your air filter occasionally, Don't go fiddling with the exhaust brake once it's been adjusted, don't drive with the exhaust brake on all the time. Replace your injectors if they are hella crappy.
I was if you can not do it Ill just come and get my truck then well Ill call you back give me 5 min.