Meter actuator part number RX, PX

[gag4o]

Hi all, first time writing

Went to the Chicago Cummins store and gave my engine serial number (79178099 made May 2006). The guy gave me the 2 parts numbers that I need 4089985RX & 4089986RX . Later I looked at the Cummins website and with the parts fitment check it tells me those are not the parts for me. Tells me 4089985 & 4089986. No "RX" suffix at the end. Also I found "PX" suffix.
So whats the difference between RX, PX and no suffix?
That was my question but here is the story if you would like to read

Time has come at 1 310 000 miles to replace the metering actuator/selenoids ( i believe) still red painted and factory. My truck at cold (summer-fall time) start is smooth as butter for the first 10-15 sec and then it starts to bruh-bruh-bruh and rpm goes slightly up-down and chirping noises every second. When it warms up to 145-150F oil temp it smooths out at idle. This for the last 2 years like this. Recent few months it started to loose power slightly. Will still do 65-70mph but feels like its a motorcycle engine..very Loud and watered down. Makes too much rumbling noise while cruising and ticks like Honda unadjusted valves when accelerating sometimes.
Pulled double fedex trailers "like a train" until Decemmber last year, had plenty of power all the time. Recent 6 months driving not more than 300 miles a night and half of the time bobtail, half time empty or once in a blue moon 10k lbs light load. Fuel consumption is north of 8.0 mpg but I feel it should be more given those facts. Two different shops made head "tune_up" recently twice and all fine they say. "You injectors are good they say". I believe those original injectors do NOT spray like or close to new for that long. No way

Someone told me to look up Rawze procedures. I did asked my mechanic to come to my garage to try this procedure. Wants to charge me as much as half of the actuators price so I figured it wont be a savings, lets just throw $ at it. I only change oil myself, some times tires... hood latches, window regulator and stuff like that. Don't have the knowledge to do the leak down test.
I did the cylinder shut down procedure. Only on cyl 1 it didn't make so much difference while all other 5 cyl the truck idled terrible when each was off. No white or black smoke. Didnt add any coolant for the last year. Not loosing oil. Sent oil analysis and came back really good, so for now no concerns on internals..just for now

[Bengy88]

Not 100% sure about the px, the Rx is a reman unit, the part number without the suffix is a brand new unit. Usually these timing and metering actuators start giving issues or are beginning to wear way before 1.3 million. Usually by 700,000 they start getting excessive side to side play or a “step” in them when you move the plunger in and out. I’ve also never seen any Cummins make it to 1.3 million without having to pull at least one injector….. especially an 870 or 871. These engines are known for leaky injectors that’s why there are so many instructionals and videos floating on the forum about them.

[gag4o]

Thank you.
That being said I am safe to purchase the RX reman part from cummins or for roughly the same price non suffic part?

I know the previous owner and also drove the truck for 3 years before i bought it in 2020. Either them injectors were replaced prior 800 000 mi mark either never. 2007 Volvo barbie truck VNL 13 speed tuned to 500 ecu Hp by previous owner. Says 400hp on the door and 500 on the scan tool. Down know which isx is this but the turbo actuator has a air hose running to it. This type is which engine spec?

[tree98]

(11-20-2023 )gag4o Wrote:  Down know which isx is this but the turbo actuator has a air hose running to it. This type is which engine spec?

The CM870 was the only ISX to have an air actuated turbo. Register your engine ser # on quickserve.com and you can get all the same service and parts
information that the dealers have.

[Nostalgic]

RX = reman
PX = new unit, often sold as reman to keep stock/supply quantities up.

I've never really been able to tell much difference in quality between the two. PX and they reused visibly worn parts and RX where everything looks brand new. I've had reman actuators leak from the plastic/plug but it happens right away so warranty has never been an issue.

[Rawze]

(11-20-2023 )Nostalgic Wrote:  RX = reman
PX = new unit, often sold as reman to keep stock/supply quantities up.

I've never really been able to tell much difference in quality between the two. PX and they reused visibly worn parts and RX where everything looks brand new. I've had reman actuators leak from the plastic/plug but it happens right away so warranty has never been an issue.

I have never gotten a PX part# that did not look brand new... cummins claims they are new stock...

so maybe...?
If you got a PX part and it was scuffed up, looked old, etc. then someone purchased it and returned it back to the stealers$it?. happens a lot, and I look out for it closely, as a lot of people buy parts, take them apart, and put bad component (that they cleaned up nicely) in its place to make scam and get their moneys back, claiming they did not need it.

[gag4o]

Great info. What about the non suffix part? If it really new and very close price as the reman then wouldn't it be better to get?

[windowrattler]

Non suffix and I think also nx are new parts.

[gag4o]

Ok guys. It is all great info for me.
I asked the Cummins customer service what is the warranty on the new part and they told me there are new part numbers that super seed the older ones
5693751
5693752
also these new numbers are new units while the rebuild is the PX number only

And last question. When facing the actuators while installed on the engine, which one is which?
Starting from left to right (front end to rear end) ?