Diesel Injectors - advice needed

[WiscoHoundsman]

I am in need of advice on if I should replace my diesel injectors on my 2015 Ram 3500 with 180k miles.

Background: I bought this truck brand new hand have kept it well maintained with mostly emissions issues through the years. Recently it has had 3-4 starts over the past 6 months where the truck shakes more than normal when initially idling until I get moving. About a month ago leaving work it did this again but also had a bunch of white smoke for 30-60 seconds it has not done this again since then.

My mechanic when asked about it said it sounds like I could have an injector going bad. He stated he could pull them and have them tested or just replace all 6.

Any advice on if I should do it “immediately” or if it’s alright to drive a few months before having the work done. Could this just have been a one time fluke with the smoke?

 

[wyosteve]

Personally, I'd replace all 6 of them. 180k is not a lot of miles on injectors, but it's no small amount either. My buddy had his go bad at 65k on his 2013. FWIW, I've been driving Dodge/Cummins since 1991.

 

[5MilesBack]

I think I've got some leaky injectors on my '01 7.3L PSD. After startup it will blow some white smoke for a few minutes until it warms up, then it seems fine. IMO if you're going to have them pulled anyway for testing, I'd just replace them.

 

[Choupique]

Agreed with above, at that age if you pull them just replace them. Generally they will outlive the rest of the truck if OEM filters are used through its life and the injectors never get water pushed through them.

You should be ok to drive it for now if there are no red flags once it clears up. There's a non-zero risk of hydrolock even with electronic injectors, so you are taking a bit of a risk. White smoke at startup means fluid on top of the pistons. Are you losing coolant, making oil, anything like that?

Your shop should be able to do an injector cutout test without taking anything apart. That may or may not tell you anything. It could be as simple as a sticking fuel pressure regulating valve, but that will generally trigger a fault code. Rough idle at startup is usually some kind of fuel issue but it could be a simple issue, like a lift pump crapping out.

Me personally, I would do some in depth electronic troubleshooting before taking anything apart or changing anything. Changing injectors is an expensive undertaking and I wouldn't do it without extremely high confidence that it was the issue.

 

[TaperPin]

High pressure injectors don’t last forever, but damn they are expensive.

When deciding on which option to go with you can think in terms of cost per mile of installing new injectors and an average lifespan, beit 250k or a different number. Compare that to the lower cost of having your injectors tested and if they are ok, your cost per mile for that until hitting their average max lifespan. If you drive much, it won’t be long before there’s little to be gained testing injectors you know are on their last legs.

Interesting he suggested injectors without looking at high pressure oil or fuel rail pressures, let alone a cylinder contribution test all from the scan tool. The contribution test cuts off each injector and the computer interprets the relative strength of each cylinder at different rpm’s and graphs it. This is a graph for a power stroke. It doesn’t automatically mean it’s a bad injector since compression could be low in an under performing cylinder.

Mechanics who throw parts at symptoms without testing are my pet peeve.

 

[WiscoHoundsman]

Sounds like I need to talk to the mechanic some more about some additional tests. I’m assuming they can do these on my truck but will find out. As for pulling the injectors and testing it seemed silly but wanted to verify. If i end up replacing I would do all 6.

In just not sure how long i plan on keeping this truck but new trucks are also expensive.

 

[WiscoHoundsman]

Are you losing coolant, making oil, anything like that?

Not that I am aware of for coolant. Oil I just changed this week and would say it’s definitely not loosing any over 5k miles and possibly increasing but don’t take exact measurements. No check engine lights or anything like that. And the smoke has only happened once. The truck is driven almost daily.

 

[jjordan355]

If you have injectors failing, replace with OEM, install a FASS lift pump at the same time, change the fuel filters after injectors and change them often afterwards. None of these parts last for ever. 180k is a lot to ask out of a stock set of injectors if filters have been neglected or poor fuel quality has been ran through that engine.

 

[WiscoHoundsman]

Interesting he suggested injectors without looking at high pressure oil or fuel rail pressures, let alone a cylinder contribution test all from the scan tool. The contribution test cuts off each injector and the computer interprets the relative strength of each cylinder at different rpm’s and graphs it. This is a graph for a power stroke. It doesn’t automatically mean it’s a bad injector since compression could be low in an under performing cylinder.

Mechanics who throw parts at symptoms without testing are my pet peeve.

I should have noted he did hook up a scan tool for maybe 10 minutes. So he could have done these things and come to the correct conclusion based on those results.