Dash DPF gauge

[Mattman]

How accurate is the in dash DPF gauge in a T660?

[Lonestar10]

not precise but it can put the truck into a derate if it gets to low but empty might have say 1/2 to 1 gallon left. problem with letting DEF tanks get low is it allows the Urea to recrystalize then the filling/emptying of the tank doesnt always "melt" the crystals and they get into the filter exiting the tank and plug it over time. its best to always fill the DEF tank every fuel stop.

[Waterloo]

I spoke with David24 about this yesterday on the phone. I explained to David what I had learned about DEF, as many of us are in the dark about this product. Not something I concern myself with, as I do not own a DEF truck, but I still want to know. DEF is basically piss. I told David that when piss sits it eventually crystalizes. When it crystalizes, bad things happen. He got that, just commonsense, but had know clue what this stuff actually is, as most guys don't, and that is understandable. He has codes popping in relation to this, I have not seen him post up the codes yet, but something is going on with the SCR DPF system on his truck. David, you need to post those codes...

On a side note...

I live in the F'n Twilight Zone... Piss to run a truck down the road, seriously?

[Camstyn]

DPF gauge is different from DEF gauge. My 14 Pete had one as does my 20. I’ve never seen the needle move on either of them, despite the 14 having needed a DPF cleaning.

[Mattman]

Right Camstyn DPF.
This truck was just cleaned before I got it, I was wondering if it was closer to be accurate or just there for looks.

[Lonestar10]

Guess I've never seen a DPF gauge that's a new one. If there is such a thing I'd never trust it it's in a soot stream and that never ends well

[Mattman]

After about 11,000 miles haven't seen my gauge needle move off of clean. Truck hasn't done a Regen parked, does them going down the highway. I have only seen hot exhaust light come on once while stopped at a red light. If my fuel economy on the dash starts reading lower than it usually does I assume it is doing a Regen at that time.
Was hoping gauge would be a little more accurate.
I try not to idle my truck. Uses about 5 gallons DEF every 1,000 miles or so.

[Lonestar10]

I beleive that gauge shows for the ASH load not when it needs a regen or not. i would guess the gauge is mainly to let you know when to replace or bake filters.

[Rawze]

It would not be hard to make a digital gauge for the dash using an arduino that shows actual DPF differential pressure. The ECM supposedly already spits out a PGN (I think it is pgn-64946, have not tested it yet though) signal that contains the diff pressure every half second or so on the J1939.

just some thoughts.