Here's Some Helpful Hints When Looking For Failing Common Rail Cummins Injectors!

Hello Guys! This is not a comprehensive look at failing CR injectors, but this is a great look at some early symptoms of failing injectors. This is a truck that I know the background on pretty well and have done a lot of work on over the past 10 years. Heck, not only did I do this injector swap, I did the last set of injectors about 120 - 130k ago too. This truck has always been run with a Baldwin 5 micron filter. If you need one for your truck cause you don't have a aftermarket 2 micron filter on there, consider helping out the channel by buying one through out affiliate link below! It doesn't cost you extra, but it does help support making more videos for the channel!

Again!!! Extra Warning here!!! There are too many possible ways for CR injectors to fail, so please don't risk a healthy motor with a set of bad injectors. Sometimes they fail slowly and sometimes the die in a blaze of ROD throwing glory!!! Don't let that be you! Pay attention and get good quality injectors in your motor, then feed them well filtered fuel!

Oh yeah, here's that affiliate link to the Baldwin PF9777 filters I mentioned above...

[haydnthompson]

Mine was doing that exact same thing but hung up longer, knew right away it was injectors. Went with DDP Patriot series eco reman injectors, great budget choice and a reliable company! Installed them today and totally got rid of the hang up and it idles way smoother and not jumping around. Super happy.

[MotorsportDiesel]

So the symptom you are demonstrating is what is commonly called "rail hang", it is a condition where the rail pressure does not drop when you let off of the throttle. Regardless of the cause which is most always excessive return from the injectors I will address the effect.

The algorithm that controls system rail pressure via the FCA, which is actually named the mprop by Bosch is operating in the upper control range of the PWM signal. In simple terms the control amount is incremental and if you could monitor this you would see that it is likely maxed out by the requested rail pressure, so therefore incrementally in a count down from say a max 255 or whatever back to desired pressure will take a longer time to increment through. The PID settings in the ECM are pretty slow to respond (increment or decrement) based upon the calibration.

What is happening is the CP3 is having to provide essentially its maximum output as it is a variable displacement pump, via the stroking of the mprop, so if it is running essentially wide open, and then the request is idle output, it takes longer for the pump to reduce its output which is evident and observable by looking at a mismatch between desired and actual pressures.

Further the degradation of the injectors could cause additional fuel to be injected as can be realized by doing a SOI test. Backleak/return should always be checked, but you like others do not have actual testing parameters that are accurate to follow, tools do exist to do accurate non-intrusive testing.

[tylerbeck]

been trying to solve this issue in my 5.9 common rail im going to look into injectors and im doing this before i drive my pickup again, everyone says its “ a common dodge thing” i knew it was a issue thank you so much

[VisionTV]

This was very helpful!! When I drive 30 miles per hour, the stuck will exhilarate at a higher speed. I had to throw it in neutral and cut it off. Never could figure out what was wrong.

[dannydyer]

I bought a 2006 single cab 4x4 5.9 with 6 speed that had about 265k on it, I don't drive her very much, 5 years later only has 292k.... no idea how long those injectors have been in there. I do a new Baldwin filter every 2500 miles, and I add Hotshot Secret fuel additive every fill up. Almost no sign of them being bad as far as I can tell, and yet, they are on my mind every time I light it up. Injectors are the Killer Dowel Pin of the otherwise awesome 5.9 24v Common Rail lol

[Simon-rjup]

This was really helpful, have had my 03 for just over a year but I'm sure it had bad injectors when I bought it

[gabrielzazueta]

What would be a fair price for 6 quality injectors installed by a reputable diesel shop? I just dropped mine off today and waiting for my quote. Thanks!

[paulphipps]

Hey really appreciated your common rail rebuild videos, my son and I rebuilt his 04. We have it running but would love to have you guys hear it run, it idles great but sounds like it has a miss when it is accelerated. It has a straight four in pipe.

[babybullsmith]

I purchased my 06 back 2014 and as soon I got back in SCarolina the injectors failed. Put a set of remans in (I treat my fuel every fill up with optilube XPD) and now I have 130, 000 miles on the odo. My question is when should I start looking to have a set of injectors in? What brand of injectors( how much) and should I go with remans or new injectors. thanks

[TheHaggertonFamily]

Are you referring to the weird chatter on the rpm as they fall on the free rev?

[TheUnknownSacrifice]

Just put on a cold air intake, from dead stock truck. Only 160k miles on the truck, whenever I get into the top end it seems like the injectors are starting to stick after adding better airflow from the cold air intake, will update if there is further problems. 🥲 also just ordered a MM3 from 5.9diesel so hopefully I’m not gonna be dropping another 3k on some 25-50% injectors 😭

[tylerrussell]

How are the industrial injection injectors holding up?

[BlazinSteelLtd]

Love the videos man! I’ve got a 2012 Cummins. Love the truck but I sometimes have a puff of greyish/white smoke come out the tail pipe when letting off the gas. If I’m in cruise control and the truck slows itself down it will spew out the smoke for a few seconds. Any idea on what would cause it?

[__WJK__]

For the past couple weeks my '03 3rd Gen will cut-out and blow white/gray smoke whenever I get on the pedal "somewhat" aggressively a/k/a not "passing a car" aggresive, just medium-ish throttle input. However, if I go easy on the pedal, I can keep the cut-out issue from happening and the truck continues to avg 17+ mpg around town. That said, I did notice the fuel pressure reading on my Quadzilla iQuad is reading in the 50s (vs the normal 10-12 psi) which I originally figured was nothing more than a bad Quadzilla lift pump pressure gauge sensor, however, now I'm not so sure and thinking the excessive lift-pump pressure may be a sign of something more ominous, such as a bad "open" injector back-feeding pressure into the rail(?) If anyone has any thoughts on what might be going, by all means, please let know... thanks!

[turboflush]

Good stuff.
Any secret stuck closed injector secret test?

[xmo]

My 2004.5 vin C
325/600
Has what feels like and sounds like a rod knock.
Under 1000 miles on a rebuilt block, head, turbo, injectors. 100% stock everything.

The knock is intermittent and very difficult to replicate sometimes. It does it at 1500-1700 rpm while cruising lightly if I feather the throttle to accelerate a bit. That's the only way it'll do it.

Is this a sign of a bad injector?
I've been to 5 diesel shops and they still can't nail it.

🙏Please and thank you.

[calitaco]

Got an 06 with 229K miles with no blowby or oil leaks. I don't drive it much but starting to notice a light black puff of smoke at start up for a second or so. I have a MM3 with custom tunes, but really don't use it since it causes it to smoke a little and it sounds like it's pinging (normal?). I don't know if the injectors are original or not and thinking about replacing them. What are your thoughts on Big Bang Injectors?

[anaconda]

Good information thanks for posting. I have a 06. 5.9 noticed truck sounded louder and noticed it is idling faster then it ever used to. Any pointers be great thanks

[feetdownguideservicewisco]

I have some white smoke at start up. Goes away after 30 seconds. Never did that before owned the truck two years now. 04.5 truck. About 190k on it. Seams a tad choppy at idle for that 30 seconds to me Drive it and it seams fine as far as power and responsiveness. No noticeable difference in anything but that. Good coolant level and oil looks mint. No programmer on the truck to read much.

I’m super scared to drive it right now as it’s never done that before. Short of buying a programmer to read rates and or rail pressure and stuff. Does this sound like injector symptoms to you? I’ll do that rev test in the morning see if it’s dragged out like your video.

[MakeAnything-]

My truck has dual cp3s, and i get a studder when starting out. It gets worse as the motor warms up. I have replaced both FCAs and the controller. Any ideas on what this could be?