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Injector noise?

17K views 18 replies 6 participants last post by  redlineRyan 
#1 ·
just noticed this noise the other day, it's obvious in drive but quiets down in park. checked my balance rates and they seem kind of all over the place, but 1 & 3 are the worst. The noise sounds like its from the passenger side so that makes me think those two are the culprit. I tried taking a video, but it's kind of hard to hear so I apologize.
The truck only has 136k on it so I was hoping not to have injectors going bad just yet :cookoo[1]:

https://youtu.be/QbOGBvhCb80
 
#2 ·
Ordered the upper engine/injector cleaner (AcDelco X66P) so I'll be doing the cleaning process (again) on Monday or Tuesday. I did it back in October and my balance rates looked perfect afterward, not sure how they could go bad so quickly... I believe I do all the right things to ensure my fuel is clean and contaminant free.
Almost considering giving LDS a call and ordering a set of 8 Bosch injectors for $2500... clean slate, and if the need ever arises for bigger nozzles down the road, at least I'll know my injectors are good
 
#3 ·
Just did a 500 mile road trip and did a double dose of optilube before I left. and upon retun, my balance rates looked much better with #3 being close to 0 and the highest rating being +/-2.. no strange noise either. Yay it fixed itself, I love when it does that
 
#4 ·
always good. I fill my filter with it every once in a while when I change it and run it through. No problems with injectors in 2 engine and 180K total.
 
#5 ·
I got too excited too soon, noticed a day later that it had returned.. ugh. same noise, same conditions. All the pulleys/belt are new, unless it's the alternator. But when i listen under the hood while in gear (only time i hear it, in P/N it's almost non existent) I can't hear anything.
Can hear it plan as day in the cab though... balance rate on #3 crept back up along with a couple others. Still no haze/smoke/etc. I have been eyeing the 30% over injectors from LDS for $2,800 lol
with 137k miles would it still be worthwhile to only replace indidvual injectors as they start to go bad?
 
#6 ·
Go buy a stethescope and listen to your engine. You can pinpoint it.
 
#7 ·
Yeah I was hovering over it again today and could hear it the best around the 1,3,5 injectors...
In other news i also noticed the wiring harness plug to the trans is leaking...:mad:
 
#8 · (Edited)
You should own a Peterbilt, 2 tractors, an ATV, 2 pickups and a car. Can be a nightmare.

Someone at the auto repair shop locked the owner's keys inside his car. While the locksmith was working on the driver's-side door lock, the anxious owner walked up and tried the passenger's-side door. It opened.

The locksmith looked up. "Yeah, I already got that one."
 
#9 ·
Yikes. You gotta just hope they don't all go down
 
#10 ·
Hey I'm just wondering if you ever figured out if your noise was definitely injectors? Are you having any other symptoms? A few days back i posted about an issue im having with my lbz. Ive been throwing the p0087 code for several weeks while under heavy load. The last time it happened the engine starting running rough even after I cleared the code, along with the identical knocking noise your truck is making. I've checked everything from the tank to filter housing. Had a friend check it out with efi scan tool. He's thinking it's my cp3 based on actual/desired rail pressure. Balance rates were pretty good. The noise is awful. Ive stopped driving it until I fugure it out for sure. I ordered a new pump yesterday but just looking for other possibilities before I tackle that job. Thanks
 
#11 ·
Still haven't figured it out yet, unfortunately.. I have an appointment in a couple weeks to bring it over to the dmax store have them listen to it.

At this point I'm pretty convinced its injector related, just need to verify which one exactly. I uploaded another video of it making noise, so hopefully someone on here can tell me if it's fuel knock or what..
I did pull a soft (hidden) code from the CTS last night, P0301, which is for cylinder 1 misfire.. maybe that's the culprit. I cleared it and will keep checking to see if it returns.

 
#12 ·
Any ideas...I'm all ears.
also, the truck feels a little light on power, but that's just from my butt dyno
 
#13 ·
My truck is making the same noise looking at replacing injector number 7 as the wife already blew my plan's for all 8..... did you ever get a confirmation of where your noise was coming from?
 
#14 ·
Just to update this thread. I've replaced 4 injectors so far, each at different times due to time/money constraints.
After each one, the noise seemed to subside.. for a while. Then it would come back. Number 2, 3, 7, & 8 are brand new (not rebuilt). Now the noise is back, and I'm looking to replace the other 4. Balance rates now are all -/+2..
Truck has 162k miles on it now.
 
#15 ·
So i still haven't done my noisy injector... So is this just the nature of the beast? Are your fuel rail pressures good? I haven't checked my rates since I've towed the camper. I ran out of diesel additive half way through the trip and just used dry fuel... noise seems worse now. Although I haven't got a full tank of additive fuel back through it....
 
#16 ·
Yeah I monitor my Desired vs. Actual and they're always close or the same. I also notice a tiny difference if i'm running extra additive vs. none at all. I believe injectors are just one of those things you replace as a set.. oh well, what's another $1400. The 4 I have replaced all looked pretty gunky, but i'm not sure what "normal" looks like for ~150k mile LBZ injectors.
 
#17 ·
Did the knocking go away after replacing the last 4? I literally have the same issue, have had it on 2 scan tools, have had a performance shop look at it, and purchased an edge insight and my the bad balance rates change daily, I know Have a big bill coming, just trying to figure out where to stick the money first. I have stopped driving the truck.
 
#18 ·
It's definitely better, sometimes when it's cold I can still hear the noise a little bit. What's kinda funny but frustrating, is the first injector I replaced (#3) now shows a balance rate +3-4 at hot idle in park Baddd
 
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