6.7L Cummins Forum

This morning while going to work, I accelerated onto the interstate and heard a huffing noise underneath the truck. Does someone have the mechanical explanation for this?

This raises another question that I've had and may be related. What is the minimum temperature the truck should be before driving after a cold start? This morning I sat for about 5 mins with the engine running in high idle; however, the OEM temp gauge didn't show any movement. Might the huffing sounds been related to some back pressure because it was too cold? Unfortunately, I only have a 12 minute commute; therefore, I don't want to create any harm by not getting the engine warm enough before operating.

Hmmmm, I know when regenerating or right afterwards while the EGT is high and running the exhaust brake I hear a Darth Vader sound. Is the Huff coming from the passenger side of the truck?

As for ideling for 5 minutes you really shouldn't. That's one of the prime culprits of the dreaded 2262 code. Start her, engage the Exhaust brake and as soon as the oil pressure is up you should get her moving.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

You sure that your wife wasn't with you?! Just kidding! I agree again with Squid. It's probably just coming out of regen when you lift off the accelerator. As for start up, the only time that I let mine run for a few minutes is if the windows are frosted up or the temp is below 0c. Otherwise I start her up, get oil pressure, turn on the EB and we're off. Then I lock out 5th and 6th gears in the city.

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2007 Ram 2500 QC 4x4 SLT TRX4-Offroad 6.7L Automatic. '08 Jeep WK 3.0L diesel-wife's DD.
1998 Jeep ZJ 4.0L Automatic Selectrac-project for our son. '98 Jeep XJ-my wife's former DD.
1965 Dodge Polara 880 Convertible 383 Automatic.

Yes. It comes from underneath the truck and on the passenger side. It even feels like a thumping sound. It occured when I pressed the throttle to speed up on the off ramp. The last time this occured was just following a mildly cold start after leaving a restaurant and pressing the throttle down for a quick entrance onto the main road. Immediately following, the check engine light illuminated. Since it went away before I could have it checked the following afternoon, I can only assume it was the dreaded
P2262.

Speaking of regeneration, though I have only a 12 minute commute with most of it within 55-70mph, I have yet to have any warning come up on my overhead computer. Might it be that because the DPF is nearing regeneration and with the acceleration of air into the DPF it was causing a back pressure? If so, why would not the computer tell me that it was about time for the regeneration to take place because the DPF was "80% Full"? It's also only occured during relatively cold conditions. It hasn't ever occured during the afternoon when I return home and accelerate onto the interstate.

The computer doesn't tell you when to regenerate unfortunatly. Just when your DPF is full. I drive over 100 miles a night and regenerate every night at least once. This is where an aftermarket display is nice because most of them will tell you when regeneration is taking place so you never reach the 80% or more full range.

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

It is possible to get into a regen mode that never goes away. Short trips just don't let the dpf get clean. You need about 20 minutes at highway rpm's

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

Actually, Vis-a-vis, after reading Squid's explanation to the other member's upshift question and the "umpf" feeling during the regen, a light went on in my head. It made me realize that I had mixed up my huff for an umpf, and that the startup of the regen may have been the cause of the "umpf." It did appear that the sound was coming from the location of the DPF.

Perhaps the solution would be for me to find a nice watering hole along a highway within a 20 minute radius. Then both the truck and I will feel regenerated.

LOL, well heck yeah!

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2007.5 Dodge Ram 3500 HD,QC, 6.7L Cummins, 6speed Auto, 4X4, Bighorn Edition.
Click for installs: Carr Steps PML Diff Cover Edge Juice with Attitude Volant Intake Hankook ATM RF10

Yup, the good certainly out weights the bad...So we find a way to work around it...When you find that watering hole let us know, we may want to use it

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7.5 3500QC 6.7CTD 68RFE Build date June 2007
Superchips tuner 3808, Boost/EGT Laser Gauge, Airaid cold intake

While on this subject, 2 days ago my Cummins started the " Darth Vader" sound (low growl, lot's of back pressure, almost like the exhaust brake is engaged at idle?). The turbo lag is very noticeable and acceleration is sad at best until the turbo spools up. This is not typical of how this truck normally runs. I drive the truck probably 80% highway, just made a round trip to Kansas 10 days ago and drove from Dallas to Houston today. The odd sound and turbo lag are still there. No CELS or lights on the dash. If this is regeneration why would it last this long?