Injector replacement and poor MPG?

[Nyoest]

Friend has an 05 6spd that had the injectors replaced about 15k ago. Injectors were new, he bought the truck new, and it has 120k on it now. He lives in Texas and I don't get to work on it much but a testing the FCA and monitoring the rail pressure everything shows fine.



His mileage dropped about 5 mpg across the board, down to 15 mt and 9 loaded with 5k or 15k.



A customer has an 06 with 86k that DC installed a new set of injectors at 50k. He is getting similar mileage but currently has a power issue. He called tonight for advice on the power issue and it got me to thinking.



Has any one experienced a similar issue? I figured if the injectors needed some run in time 15k would have been enough.

 

[cerberusiam]

Injectors need no run in time. They either work correctly or don't from the start. That concept is a dodge to avoid addressing the real issue.



That much of a drop in mileage is a pretty good indication of injector wear in remans that was not found or just ignored because it was in "spec".



If the injectors was the only thing changed and the driver is doing things the same way with the same weights there not a lot of question about where the difference is.

 

[Nyoest]

Cerb that's along the lines I was thinking on the 05 but he 06 was done at dodge. Kinda hoped they would be a bit better.

 

[cerberusiam]

Cerb that's along the lines I was thinking on the 05 but he 06 was done at dodge. Kinda hoped they would be a bit better.

What makes you think a Dodge provided reman is any better or worse than another source? The track record on remans has been bad, no matter where they come from. The Bosch remans have not been any better than others either. Its hit or miss if they work decent and do NOT drop the mpg.



Bosch has decided they have protocols for rebuilding these injectors, now that demand for new has so far outstipped there ability to produce them. Untill that happened they would not budge on rebuilding, or, even release the key parts needed to rebuild them.



The 3 issues with remans I have first hand knowledge of, all of them were resolved by replacing the supposed good remans with a NEW set. Some have reported going back 2-3 times and having Dodge change injectors until the truck ran decent again.



There is a set of published specs that Bosch puts out that says this range of tolerances are considered good, and, this range of test bench specs are considered good. It means diddly when you put them in the truck and loose 30% mpg, have rough idle and smoking, etc, etc.



If the specs are not on the tight and low side of every single parameter the results are usually not good.

 

[CKelley1]

ask him if the 06 got about the same mpg new as it get's now. i bet it did. to keep the heat down they used smaller nozzles than is needed for high efficiency, as the nozzles wear to larger openings the mpg usually increases when it get's about 80k on it it should get it back. he needs to add a 2 micron filter to prevent excessive wear. if he will change the nozzles to ddp 50 hp he can get it back now

 

[Nyoest]

Cerb do you think swapping the nozzles for something like the ddp 50 as suggested will do anything or are both these guys ace out and need to drop 3k on injectors?

 

[cerberusiam]

Cerb do you think swapping the nozzles for something like the ddp 50 as suggested will do anything or are both these guys ace out and need to drop 3k on injectors?

Flip a coin, thats the odds. Nozzles are only one aspect of performance\economy.



The DDP's nozzles MAY help if they got nozzles that are at the limit of spec or just worn the wrong way. There is a whole science around size and shape of the actual holes AND the impact on performance\economy.



Won't help a bit if the internals are wore enough to bypass more fuel than originally designed. It may make it worse or stay the same.



Swapping nozzles WITHOUT making other changes is usually a zero sum game. It will pull like crazy and run better with no increase in mpg, or, even a drop. Seen that first hand too even before I had a good perspective on the CR's.



There is simply no way to tell where the issue is until you start swapping parts. Nozzles are definitely cheaper so investing in a good set of DDP 50 tips is not a total waste. If that doesn't help, or help enough, the next step is the bodies themselves.

 

[Nyoest]

That makes sense. I haven't had to deal with many 5. 9 HPCR problems outside of a FCA or lift pump. Just not that many dodges around compared to the Duramaxs. The dmaxs went through a similar period with junk remains but it seems to be resolved now.

Can you reccomend a good source for new injectors?

 

[cerberusiam]

I believe TCDiesel has new CR injectors for sale. I believe he can also get custom nozzles but not sure which ones.



Scheids and Wicked Diesel would also be another source to check. I am sure DDP and II could also get new if they are available.

 

[S.Morris]

I just got a set of NEW injectors from TC last week and installed in a early 03. It had 8285 hrs on it and was first injector change.

His service was fast and process was glitch free. I will use his company again when the need arises if time allows... .....



I tried to get NEW injectors for an 04. 5 about 3 months ago and at that time there were none available and ended up having to go with remans from Cummins