Join Date: Aug 1999
Location: Kaysville UT USA
Feedback Score: 0 reviews
As mentioned DEF is used to reduce NOx.
NOx is produced at high combustion temps. ( Think when the Turbo is in use)
If you have an Edge CTS or other gauge you can see your EGT temps at the 1st probe. High temps mean you are probably using DEF. Low temps you are not.
So when your truck idles at 750 rpm it is showing 300° EGTs. Running at 65 mph on level ground will show 1500 rpm and maybe 500° EGT. Accelerating up the onramp might see 20 psi boost on turbo and 1000° EGT. And towing 13,000 lbs at 70 mph will more like 800-900°, And trying to hold that 70 mph up a 7% grade will read more like 1100°
I don't know what the kick in temp is where DEF starts to inject. But it's safe to say at idle you are not using any and at full throttle you are.
Your emissions in the exhaust pipe are really two separate parts. DPF to clean soot and SCR to remove NOx.
On another note, Your Passive Regens will happen anytime your EGTs exceed 572°. So if you get over 572° and are not producing excess Soot, Your passive regen will burn off the soot in your DPF.
15 F350 CC Lariat SRW LWB Ruby Red, Ultra Predator Wheels with Toyo 295/65R20, BAKflip Fibermax tonneau, Diesel Products LED lights in the rear bumper and 20" light bar in the front bumper, Firestone Airbags and Airllift Wireless compressor.
11 F350 CC Lariat SRW LWB Tuxedo Black Sold at 145,000 milesl