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I don't see how the CP3 can limit RPMS. From what I understand it is just a pump tied to the engine that creates rail pressure and has no way to cut fuel at a certain rpm.
 

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I don't see how the CP3 can limit RPMS. From what I understand it is just a pump tied to the engine that creates rail pressure and has no way to cut fuel at a certain rpm.
I understand the CP3 will start to limit FUEL over about 3,000rpm but not RPM. I will find a more knowledgeable local person to deal with.
 

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I don't see how the CP3 can limit RPMS. From what I understand it is just a pump tied to the engine that creates rail pressure and has no way to cut fuel at a certain rpm.
The pump overspeed limit is at 4000rpm. The injector overspeed limit is 3500rpm. It's the high speed governor that limits the rpm at 2600 rpm and several settings that need to be raised to reach 3200.
I've tuned one of these to rev to 3200rpm and a 6cyl with this same ecu to 3500rpm. Besides just raising the limiters, there are several maps that end just over 2600rpm that I've also re scaled.

The ecu controls how much pressure the pump puts out, so it could definitely limit rpm. However, I doubt that is what they are doing. The rail pressure map maintains pressure to 2900rpm and then at 3000rpm it drop way down to 25mpa.
 

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So will anyone tune these Yet? Mine is in route to my house.
 

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I sent my ECU to jr2185 to re program. I was just after a bit more RPM and power.
Unfortunately that was just when I was taking the truck off the road for the winter and only got a short drive down the street with the new program. It had more RPM and a bit more power which is all I was after. I was not looking for more power since it pulls my little 5th wheel fine the way it is.
Just today I pulled the truck into the shop for its spring cleaning before insuring it for the summer so I should have an update in a few weeks.
 

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I have been driving the truck for the last few weeks and like the improvement, just wish I did not have to wait 6 years! ;>)
The extra RPM is very nice. I seldom get to 3000 RPM before shifting but its nice to know there is a bit more if needed.
The little extra power is also nice and in a couple of weeks I'll be heading out on holidays with my 5th wheel and will report again.
There was very little power added below 1800 RPM which is now more noticeable with the extra power above 1800.
 
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