Rawze.com: Rawze's ISX Technical Discussion and more
Can’t get mpg up - Printable Version

+- Rawze.com: Rawze's ISX Technical Discussion and more (http://rawze.com/forums)
+-- Forum: Big Truck Technical Discussion... (/forumdisplay.php?fid=1)
+--- Forum: Ask Your question... (/forumdisplay.php?fid=45)
+--- Thread: Can’t get mpg up (/showthread.php?tid=9118)



Can’t get mpg up - EliteT660 - 09-23-2023

Hey everyone. So o have a 2009 t660 cm871 roughly 800k I started driving by the boost guage 58mph. Somedays I get 7.5-8 mpg and some days 5.5. Mpg. What am I doing wrong. I did egr tune. Replaced all sensors with Cummins oem. I keep boost close to zero while driving and never go over 20 psi while climbing. Any help would be greatly appreciated.


RE: Can’t get mpg up - Rawze - 09-23-2023

Assuming it is not deleted... What does the regen history look like?. Maybe post a screen shot. ... or is it de-mandated?.


RE: Can’t get mpg up - EliteT660 - 09-23-2023

I don’t have insight set I’m working on that. But I have been getting random dpf/doc alarms and when I get under 5 mph I often get the hot exhaust light. So I’m assuming the system is regening to often


RE: Can’t get mpg up - Rawze - 09-24-2023

(09-23-2023 )EliteT660 Wrote:  I don’t have insight set I’m working on that. But I have been getting random dpf/doc alarms and when I get under 5 mph I often get the hot exhaust light. So I’m assuming the system is regening to often

Very likely so, and how old are the DPF/DOC elements?. When was the last time you removed them and had them professionally baked out, de-ashed, and flow-tested?. They are due for this every 2 years or so .. BEFORE the check engine lights start coming on, or at first signs of it wanting a parked regen.