Fehlersuche bei Golf 6 TDI 66kW (5K1) | Posts 24+

As far as I can tell, there is no official return volume or quantity specified by the manufacturer for the CAYC.

The guideline specifies a test for the pressure relief valve.

A residual pressure of one bar is always required for control purposes.

Otherwise, there is also a vacuum test at the return line, which should be maintained at -500 mbar for 30 seconds.

If not - Injector is faulty.

Do you have any tips on how to remove stubborn residue that's stuck to the injector seat? I have a brush set, but even with that, I can't get it 100% clean. What "agents" or "substances" can be used without damaging the material?

Thank you very much.

hauminix wrote:

Do you have any tips on how to remove stubborn residue that is stuck to the injector seat? I have a brush set, but I can't get it 100% clean with that either. What "agents" or "substances" can be used without damaging the material? Thank you very much

.
No. Because if something is stuck there, the injector was never properly installed. Metal on metal. There's no room for junk.

Please do not use sandpaper or similar abrasive materials under any circumstances! If corundum particles fall into the cylinder, everything inside will be ground up.
I would plug the nozzle opening with a conical wooden stick (to prevent anything from falling into the cylinder) and then try my luck using skewers/a cleaning cloth/brake cleaner.

Best regards, Rainer.

Thank you, Rainer.

I borrowed some caps to put in the openings so that nothing can fall into the combustion chamber. I also have brake cleaner. I just wanted to make sure I wasn't using any chemicals that might react with the metal. Today, I'm going to try to clean all four headlights using a scouring pad and brake cleaner.

The injectors have now been inspected and overhauled.

The condition of the injectors was not good.

Cylinder 1: bad.
Cylinder 2: good (replaced 10,000 km ago).
Cylinder 3: very bad.
Cylinder 4: unusable.

Now, let's clean the injector sleeves again to make sure they are perfectly spotless.

Why are some tests failing even though the actual values are within the specified range plus or minus the tolerance?
Can you show me the results for Injector 2?

He tested the second one for me "off the books" for free, but he didn't provide me with a test report. He only told me verbally that he passed all the tests and that he's okay.

I haven't seen a grade that I considered a failure, but it should have been within the passing range. Sometimes, you almost make it.

My mistake, I had viewed the image on my phone and was completely wrong .

Okay, but Injector 4 is very close to the tolerance limit with a deviation of 0.02. But that's why we have those values, isn't it? Out is out.

Did you have any more measurements taken after the repair?

Even experienced people can sometimes make mistakes, and for a new quantity deviation code, it should actually be implemented in a way that allows them to be correctly programmed into the control unit.


For a blank injector seat, a honed recess can also be used, even in very hard cases. But really, only very carefully and by hand.
It's really just about getting the seat back into a usable condition, in case there are significant defects.

He gave me 3 refurbished items with test reports. The values of these are good and within the acceptable range, and they include a 2-year warranty. The price is absolutely reasonable when compared to the current market prices for new nozzles.

Hi,
Regarding the test results, I have my own humble opinion. The abbreviations VM, EL, LL, and VE need to be explained if one wants to understand what was done. But who checked it, with what equipment, and where do the tolerances come from?
- Cylinder 1: Fuel injection quantity (low pressure) is below the minimum tolerance. Fuel injection quantity (high pressure) is below the minimum tolerance at 900 bar. What was the measurement accuracy?
Cylinder 3: The injection quantities for the low-pressure injector (VL), the main injector (EM), and the variable injector (VE) at 900 bar are approximately 10% too low. The question is, what would have been compensated for by the volume matching and switching time correction in this case.
Cylinder 4: Values similar to cylinder 3, too low, but with larger deviations.

All the nozzles appear to be sealing properly at 1600 bar. That's why the question is whether the obvious carbon buildup was actually caused by these injectors. We'll see.
hg
Herbert.

Hello Herbert,

I will see it soon. Right now, the cleaning of the shafts is scheduled. The test was performed by a certified company that specializes exclusively in fuel injectors and turbochargers.

Is it okay to use something like that to remove any remaining color residue from the injector seat? Of course, use a small plug to prevent anything from entering the combustion chamber.

https://www.autoteile-direkt.at/nigrin-74028-metall-politurpaste-75ml-820577?gclid=Cj0KCQjw8eOLBhC1ARIsAOzx5cEnlu7_7RGlM2XBNk6lzo0bHuruqnK7HvywftLFt046e60j42NbWAsaAmCzEALw_wcB

Or rather, stay away from it?

https://www.amazon.de/BGS-9324-Injektor-Schacht-Sitz-Reinigungs-Satz/dp/B0746H3PYW?pd_rd_w=jbK2R&pf_rd_p=de50c8a5-0a49-4e71-9d9b-5db14442a6d1&pf_rd_r=MCH9G5A7D51DZ88A1CSQ&pd_rd_r=456cc75b-d18c-4ab4-8402-e51fb79d07f6&pd_rd_wg=OZ2sE&pd_rd_i=B0746H3PYW&psc=1&ref_=pd_bap_m_rp_1_sc

Such a set is actually very helpful.
My professional-grade tool, but it definitely works for cleaning.

That's exactly what I used .

The seat is now completely clean. The injectors (rebuilt) have been installed. New codes have been communicated to the control unit.

The variations between the individual cylinders already look better. The stuttering is completely gone.

Tomorrow, I'll start by performing the initial calibration for small quantities, and then I'll check the soot values during a test run. In the readiness check, I'm still having a small issue with the lambda sensor heating - it's showing as red (failed).

I would like to know on what basis the "soot value" is determined. What data and sensor technology are used for this?

Let's start with the good things. The car runs very smoothly. The stuttering is gone, and he's also completely calm during recovery.

Unfortunately, the behavior of the soot values has not changed. Could the DPF be causing the problem?

Near the end of the journey, he stopped the regenerative braking process because the fuel level dropped into the reserve.

The air mass, measured in g/s, can be converted to mg/stroke given a specific engine speed. However, converting the raw voltage of the oxygen sensor to a lambda value is not possible without using certain parameters. The lambda value would indicate the amount of excess air present in the exhaust gas.
Ultimately, it boils down to whether the engine is producing excessive soot, the filter is simply clogged, or a sensor on the exhaust side is malfunctioning. The differential pressure sensor would still be affordable, but otherwise, I wouldn't immediately start replacing other parts based on the problem.
The performance is already quite concerning, but could you please record it again, this time including the relevant measurement values?
hg
Herbert.