Engine/Transmission (1998.5 - 2002) Injectors

[GMocanu]

I installed RV275s. The stock injectors were really sooted up. I can scrap off chunks of soot. It appears that some of the holes in the nozzle have been blocked or obstructed by this build up. My truck runs a whole lot better now and I believe that some of that is due to having clean injectors.



My question is what caused this build up? How can I avoid this happening to my new injectors?



Now I will add that I do run the engine at low RPMs from time to time. I'll cruise, empty, at 40 mph in 6th with the RPMs down around 1100 - 1200. The truck has 42k on it but I have only had it for 3. 5k so I don't see how my driving could have gotten them that bad in such a short period. I have no idea how the truck was driven before I got it.

 

[jerrethomas]

sounds to me like it was idled for long periods of time before you owned it.

 

[RustyJC]

If the previous owner ran crappy fuel, that could explain it as well.



Rusty

 

[Riflesmith]

Where in the United States is one expected to get good diesel fuel? Fuel in North America has the poorest specs in the entire world. Lowest acceptable cetane rating, highest allowed amount of sulfur and aromatic compounds. It is swill, hence the carbon buildup.



The new ultra low sulfur diesel fuel will have 15ppm sulfur max, 10% aromatic compounds max, and a minimum cetane of 50 to 55. It will be a significant improvement over the junk we have now.

 

[LSMITH]

Get out and pull something. Maintain EGT's of 1150-1300 for as long as possible, at least an hour within one tank of fuel. You will be amazed at how well it runs when you unhook. The temps will also clean all the crap out. An injector cleaner like Power Service Diesel Klean will help too if you treat a tank every coulple tanks.

 

[Phil Stuart]

How many of you have...

replaced the injector supply tube "O" rings that are located on the injector tube when swapping injectors?Not the injector "O" rings themselves mind you.



I am going to put in new 275's myself here in a week or so and saw in the FSM that the injector tube "O" rings should be replaced when installing injectors to eliminate the chance for leaks that can happen with a used "O" ring.



I didn't want to take any chances, so I called Cummins and ordered a set of 6 along with the air intake connection gasket to be on the safe side.





Phil

 

[LSMITH]

Phil, I have had a couple sets of injectors in my ride and have not changed the o-rings. It is not necessary to change them unless you have an oil leak at the injection lines on the head. They do not seal the fuel system in any way, only oil and even then it is not under pressure. I would keep them on hand and replace only the ones that leak after you change the injectors. I would bet lunch you still have all six in your toolbox 3 or 4 sets of injectors from now... ... .



I also do not take off the airhorn when changing the injectors. I find it is not necessary, nor helpful to do so. It saves a lot of time leaving it on also.

 

[Phil Stuart]

Originally posted by LSMITH

Phil, I have had a couple sets of injectors in my ride and have not changed the o-rings. It is not necessary to change them unless you have an oil leak at the injection lines on the head. They do not seal the fuel system in any way, only oil and even then it is not under pressure. I would keep them on hand and replace only the ones that leak after you change the injectors. I would bet lunch you still have all six in your toolbox 3 or 4 sets of injectors from now... ... .



I also do not take off the airhorn when changing the injectors. I find it is not necessary, nor helpful to do so. It saves a lot of time leaving it on also.

Thanks for the reply.



I wasn't sure about the "O" rings so I'll have them on hand just in case along with the intake grid gaskets that I got.



I was hoping that I could change them out without having to remove the intake air horn assy. I guess there's just enough room to move the lines out to pull injector on #1 and #2 cyl.



Cheers



Phil