Good morning all - i would to use the group as a sounding board for injector deviations on a 2014 with cnrb. Have about 460k km on the clock. This past weekend I had my vcds connected, I note that #3 is +2.35 mg / stroke and #4 is -1.05. The car runs fine, good fuel economy, etc. I'm curious if there is a threshold between good and bad, or more likely its the differential across the 6? No trouble codes were shown. I am planning on a valley reseal soon, I will ensure the intake is cleaned well before it goes together. I cant see how that would affect it, but stranger things have happened. I will run a heavier dose of injector cleaner and try to make a trend when i'm driving. I'm pretty sure I know the answer to my own question - i'm assuming that one is kaput and the other is on its way.Thanks in advance!
acceptable injector deviations
Lance_1
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Good morning all - i would to use the group as a sounding board for injector deviations on a 2014 with cnrb. Have about 460k km on the clock. This past weekend I had my vcds connected, I note that #3 is +2.35 mg / stroke and #4 is -1.05. The car runs fine, good fuel economy, etc. I'm curious if there is a threshold between good and bad, or more likely its the differential across the 6? No trouble codes were shown. I am planning on a valley reseal soon, I will ensure the intake is cleaned well before it goes together. I cant see how that would affect it, but stranger things have happened. I will run a heavier dose of injector cleaner and try to make a trend when i'm driving. I'm pretty sure I know the answer to my own question - i'm assuming that one is kaput and the other is on its way.Thanks in advance!
Good morning.
It isn't really "documented" anywhere that I've seen....
Typically, anything over 1mg would make me investigate further.
There is a discussion on RT where people try to give examples of what a "good running" engine should have.
I have also personally tried to decipher the set-points as far as what might be acceptable ranges.... no dice.
Also, note that injector deviations aren't necessarily an indicator of injector health... it's simply an indicator that something isn't "right" in that cylinder... so it could be compression issues, injector issues, carbon buildup on intake valve, etc.... further investigation is required.
Are you taking the reading at full temp idle?
It isn't really "documented" anywhere that I've seen....
Typically, anything over 1mg would make me investigate further.
There is a discussion on RT where people try to give examples of what a "good running" engine should have.
I have also personally tried to decipher the set-points as far as what might be acceptable ranges.... no dice.
Also, note that injector deviations aren't necessarily an indicator of injector health... it's simply an indicator that something isn't "right" in that cylinder... so it could be compression issues, injector issues, carbon buildup on intake valve, etc.... further investigation is required.
Are you taking the reading at full temp idle?
Here's a sample of one of the last times I looked at mine about a year ago. (less than 1/2 your odo but it gives you perspective as to what decent state is)
Code:
Saturday,16,March,2024,15:55:49:38535
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 7 x86
VCDS Version: 23.11.0.0
Data version: 20231027 DS351.0
www.Ross-Tech.com
VIN: License Plate: INJ_DEV
Address 01: Engine (7P0 907 401 K)
15:55:35
IDE00365 Injection quantity deviation cylinder 1 0.05 mg/stroke
IDE00366 Injection quantity deviation cylinder 2 0.10 mg/stroke
IDE00367 Injection quantity deviation cylinder 3 -0.05 mg/stroke
IDE00368 Injection quantity deviation cylinder 4 0.16 mg/stroke
IDE00369 Injection quantity deviation cylinder 5 -0.14 mg/stroke
IDE00370 Injection quantity deviation cylinder 6 -0.12 mg/stroke
IDE01922 Vehicle distance driven 201626 kmSavage - thanks for the quick response. Yes it was fully warm after returning from a quick highway trip, and not in regen mode. I didnt consider the compression, etc. Makes sense. At almost 400 usd per injector not just going to just throw two in. I'll do some trending, clean the intake and valves in the near future, and go from there. I may also pull the return lines, and try to measure the outflow of each hopefully without soaking myself with fuel. I assume DPF health and a multitude of other factors come into play as well.
CR injectors do wear, so I'm sure yours are worn.... but you need to do a little more digging to see if there are other contributing factors.
Carbon buildup would certainly be expected at the odo reading.... I recall from other metrics I've asked you for previously, that your DPF is also full beyond documented capacity....
You're going to have the intake off for the valley reseal anyways, so it's a good time for removing carbon. It would be worth checking out your compression if you're able to.
Honestly though, if you have noticed any degradation in performance & FE, I would almost ignore all the metrics.... it can't be that bad if you're not loosing anything!
Here's the other post I was mentioning for your reading pleasure.
PD and CR Injectors -- Normal Compensation Rates for Reference Comparison
Carbon buildup would certainly be expected at the odo reading.... I recall from other metrics I've asked you for previously, that your DPF is also full beyond documented capacity....
You're going to have the intake off for the valley reseal anyways, so it's a good time for removing carbon. It would be worth checking out your compression if you're able to.
Honestly though, if you have noticed any degradation in performance & FE, I would almost ignore all the metrics.... it can't be that bad if you're not loosing anything!
Here's the other post I was mentioning for your reading pleasure.
PD and CR Injectors -- Normal Compensation Rates for Reference Comparison
Thanks for that link! Yes the DPF was beyond capacity - but no codes or warning lights. I agree about leaving things alone, I guess the big concern is if it turns into a squirt gun, I will torch a hole in the piston then I will be sad. For starters Ill give the intake system and valves a good cleaning. I was considering pulling the DPF and having it cleaned. Again I had reservations - if its acting fine why muck with it. With my luck it would be damaged with the cleaning.....but if I am well beyond calculated capacity and the PD is getting a little high, could be worth it.
Just remove it and clean it yourself using oven cleaner and low pressure water for flushing it out... if the PD is climbing, it may light itself up if you keep ignoring it.
That's an inexpensive approach to getting more kms out of it.
That would solve the problem, kind of like a self cleaning oven, no??
In all seriousness I hadn't heard of oven cleaner - will need to look into that. I had heard of dishwasher tablets.
Is this based off of driving with warm engine, or idle with warm engine? I am getting +-1.50mg stroke while driving.
Full temp idle
I assume the deviations increase at speeds, and under varying acceleration. For example, less than 1.00mg/stroke at full temp idle is normal, while if it passes 1.00mg/stroke under acceleration it is still normal?
As load and rpm changes, they will fluctuate. I'm not aware of any suggested ranges you should be in while driving as there are way too many variables.
Just as a partial update. I resealed the vee, so while it was apart I gave the intake a good cleaning. The valves and ports were very clean to the point I did not do any past the first one. I didnt have my inspection snake camera available, and I was concerned working with limited vision leaving a piece of crud loose, or a wire bristle unseen to get digested. I had no reservations leaving it as it was basically a thin layer of soot only. The intake got worse moving away from the intake ports towards the inlet to the intake. The plastic tube that the egr mixes in and the motorized valve on the intake were horribly carboned up. That valve would not have been able to move. Gave that all a good cleaning. I think the car runs better now. Will get a few miles on it then rescan the deviations. The next step will be to clean the dpf.
the one thing that I did notice is that the intake was really glued down. Im curious if when I had the oil cooler replaced a few years back they used an adhesive instead of new rubber seals. There was a coating of some sorts on the head mating surface. The seals on cyl 3&6 looked like they were stained by carbon on the sealing face. I wonder if the seals were reused. They were stiff. The new ones were pliable. It looked to me like it was a boost leak. Pure speculation but if they use glue to reseal it, then when sliding the intake into place, it was pushed out, that would have been a leak.
Interesting you say cylinder 3&6 those give me most of my problems on deviations
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