Cummins Diesel, Question.

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Allen Maberry

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Winchester IL .
Ram Year
2005
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Cummins
Hello Friends, My 2005 - 2500 - 4x4 Cummins Diesel With a Automatic Transmission --- It Runs Perfect. But when you let up on the accelerator, It keeps going at the same RPM for a Quite a few seconds, And when you have it in neutral or park and rev it up to any given RPM, Then let up on the accelerator, It will hold that RPM for Quite A While, Then (Very Slowly) come back down to a idle. I am wondering, Is that a Bad Throttle position Sensor or what ? It had a New and injection pump less than 8,000 miles ago. New / Rebuilt Injectors, New Fuel tubes and Fuel Lines less than 20,000 miles ago.Thank You All.

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mtnrider

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6.7 Cummins
I'd be a little suspect of the rebuilt injectors. Sounds like they are not closing. Rebuilts don't always have the best reputation. Are you getting any white smoke when you start it cold in the morning?
With that said, not a lot of Diesel folks on here. Might want to ask over on the Cummins Forum?
 

Dennis Shellito

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Ft. Morgan, CO
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Cummins IBS
I think your problem is a faulty accelerator position sensor. I have never changed one, but I have read about the same scenario you have posted and this was the fix.
 
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Allen Maberry

Allen Maberry

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Winchester IL .
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I'd be a little suspect of the rebuilt injectors. Sounds like they are not closing. Rebuilts don't always have the best reputation. Are you getting any white smoke when you start it cold in the morning?
With that said, not a lot of Diesel folks on here. Might want to ask over on the Cummins Forum?

Thank you, I am New to this Forum, Really don't know how to use it yet, But it said I am on the Dodge Diesel Cummins page at the top of this page - What am I doing wrong ?
 
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Allen Maberry

Allen Maberry

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Winchester IL .
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2005
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Cummins
Thank you, I am New to this Forum, Really don't know how to use it yet, But it said I am on the Dodge Diesel Cummins page at the top of this page - What am I doing wrong ?
 
Joined
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Indiana
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2006
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5.7l Hemi
When you rev up a common rail you are spiking the rail pressure and that pressure has to go thru the injectors to bleed off. Slow rpm drop is normal. however get a video so we can see better on whats going on.
 
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Allen Maberry

Allen Maberry

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Cummins
Thank you very much, I am starting to hear that a lot. Also Maybe it's because I am just not used to it ? I have never had a truck this new, 2005, I am used to First Gen. Dodge Cumminns Trucks, With the mechanical pump, You Rev it and it falls back to idle immediately.
 

Fast69Mopar

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2004
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5.7 HEMI
Thank you very much, I am starting to hear that a lot. Also Maybe it's because I am just not used to it ? I have never had a truck this new, 2005, I am used to First Gen. Dodge Cumminns Trucks, With the mechanical pump, You Rev it and it falls back to idle immediately.
On a 5.9 Common Rail setup, the issue you are describing is from the injectors. Rebuilt injectors can cause slot of problems if they are not done correctly. The seals in the injector are likely bleeding off fuel pressure once the injector has closed and that is what is keeping the RPM up and coming down slow and it probably stutters while coming down.

Think of it as a needle and seat and the seat leaking fuel into the carb causing a rich condition.
 
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