Fuel Injection Deviation 2.5 TDI BDG - Out of Spec

Hi!

I just took a short test drive. Actually, I was mainly interested in the generator load, but I thought I might as well log the idle speed at the same time.
Unfortunately, cylinder five was above the limit of 1.5mg per stroke.
Here are the values.
Would you try to find the cause of the problem, or is it acceptable as long as the car drives well otherwise?
It's also interesting that all the cylinders are showing a negative reading - could cylinder two potentially have a problem?

Best regards,

Florian.


Sunday, March 21, 2021, 12:59:41:63257
VCDS -- A VAG/VAS emulator based on Windows, running on Windows 10 x64.
VCDS Version: RKS 20.4.1.1
Data as of: 20200709 DS317.0
http://shop.dieselschrauber.org/en

Dealer/Workshop name: Florian Meppen.

Vehicle Identification Number:
License plate: HEI DU 35
Mileage: 171928. Repair order:



"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."
"Die Sonne scheint hell, und die Vögel zwitschern fröhlich. Ein leichter Wind weht durch die Bäume, und die Blätter rascheln leise. Es ist ein wunderschöner Tag, um draußen zu sein."


Address 01: Engine Control Module (8E0 907 401 T)

12:59:27
766 /min Motor speed (G28)
82.5°C Coolant temperature (G62)
215.9 mg/H - Exhaust Gas Recirculation (Target Value)
215.9 mg/H - Exhaust Gas Recirculation (Actual Value)
81.4°C Oil temperature (G
14.21 V - Voltage (terminal 30)
-1.57 mg/H Injection volume deviation (Cylinder 3)
-0.63 mg/H Injection volume deviation (Cylinder 1)
-1.25 mg/H Injection volume deviation (cylinder 6)
-1.02 mg/H Injection volume deviation (Cylinder 4)
-2.20 mg/H Injection volume deviation (cylinder 5)
35.2% Generator load.

Hello.

Quote:

It's also interesting that all the cylinders are showing a negative reading - could cylinder two possibly have a problem?

Plausible. Are the auxiliary components and belt tensioners okay?
Do the injection quantity deviations also not migrate?

Consider this suspicious: The sum of all deviations from the norm is approximately zero. This may indicate a potential problem with cylinder 2. Are the camshaft and compression okay?
Possibly, the injector nozzle holes in cylinder 2 are also clogged with carbon deposits.

Best regards, Rainer.

Hello Rainer,

Thank you for your reply.

At least there's no noise coming from the auxiliary components; however, I would need to check the belt tensioner.
The engine has never been opened, not even the VDD (valve distribution device), which is why I unfortunately can't make any informed statements about the camshafts.

I almost exclusively use Aral Ultimate Diesel, but of course, an injector can still get clogged.
I suppose I'll probably have the compression checked, as that can be quite informative.

The idle stability has actually changed over time. Cylinder five was initially at -1.5mg per cycle and then, at some point, it shifted direction and went below -2, although it wasn't a continuous "drift," which might be helpful information.

The battery is quite worn and will be replaced soon, but I had fully charged it before running the diagnostic. Therefore, it shouldn't have any impact on the idle behavior, right? Also, the generator load wasn't particularly high.

Hi,

When I said "wandern," I meant whether the highest value shifts from one cylinder to another. Since the mechanics of the cylinders are unlikely to repair themselves or swap cylinders, this would indicate problems with the timing belt and auxiliary components.

Best regards, Rainer.

Hi,
The injector combination with the needle lift control is located on cylinder 2. Unfortunately, it is not possible to swap it with another cylinder (which would allow you to "move" the fault).
What you can do:
- Compression test to rule out mechanical faults;
- while simultaneously comparing the carbon buildup on the injector nozzles (by looking through the holes for the glow plugs);
- Remove the nozzle in question, clean it in an ultrasonic bath, and have its opening pressure checked.
I had a weak cylinder 2 on the 1Z engine, even with perfect compression, and I couldn't completely eliminate it, not even with a replacement injector.
hg
Herbert.

dieselschrauber wrote:

Hi, When I said "wandern," I meant whether the highest value shifts from one cylinder to another. Since the mechanics of the cylinders are unlikely to repair themselves or swap cylinders, this would indicate problems with the timing belt and auxiliary components. Best regards, Rainer

Thank you for the clarification, Rainer!

No, the values and their trends relative to each other remained constant. This likely argues against the use of a belt drive.

Herbert wrote:

Hi, The injector combination with the needle lift control is located on cylinder 2. Unfortunately, it is not possible to swap it with another cylinder (which would allow you to "move" the fault). What you can do: - Compression test to rule out mechanical faults; - while simultaneously comparing the carbon buildup on the injector nozzles (by looking through the holes for the glow plugs); - Remove the nozzle in question, clean it in an ultrasonic bath, and have its opening pressure checked. I had a weak cylinder 2 on the 1Z engine, even with perfect compression, and I couldn't completely eliminate it, not even with a replacement injector. hg Herbert

Hello Herbert, thank you for the reply!

I plan to tackle that in the medium term. The engine is completely untouched except for the glow plugs and the dual-temperature sensor (okay, the timing belt, water pump, and related components were replaced as a precaution at 109,000 km). Accordingly, after seventeen years and a considerable 173,000 km, some parts might be starting to age.
I will let you know if I find anything out.

Hi!
Here's a quick update: I've already been to my friend, the car mechanic.
There, the largest outlier was 1.57 mg per injection, which was only slightly above the threshold.

Since the engine is running perfectly smoothly, doesn't require any oil, the fuel consumption hasn't changed, and the error memory was even empty, we decided to leave it as it is for now.

If anything changes in the way the engine is running, we'll need to investigate further, but at least my friend didn't see any reason to dig deeper.

If anything changes, I'll provide an update.


Best regards,

Florian.

Thank you for the feedback!