Injector Wear: Causes, Symptoms & Prevention

Hello everyone.

"I recently replaced the fuel injectors on my '98 Passat (AFN engine) and would like to get some opinions on whether the condition of the injectors is normal for 170,000 km. I haven't seen anything like this before, and I was a bit surprised by the condition, especially the discoloration and buildup. It was driven mostly in the city for the last 10,000 km, about 20 km per day. It didn't smoke excessively before the replacement, but it also didn't pull very well."

Best regards, R. Mark.

Hello R.M.,

Certainly, the nozzles could look better, but I don't think the carbon buildup is excessive or concerning. It's probably because the vehicle was driven a lot in city traffic.

Did you check the spray pattern before disassembling it?
Much worse are deposits in the immediate vicinity of the nozzle openings. These are sometimes recognizable as small craters. They can hinder atomization and lead to incomplete combustion, with the well-known consequences.

Regards,
Alex.

No, I didn't check the spray pattern. A common consequence of poor atomization would be soot formation, but that wasn't the case. He passed the inspection three weeks ago very well; the values were well within the acceptable range. (But I did cheat a little, using a plant-based oil additive and a special Bosch mass airflow sensor ).
However, since there seems to be a lack of performance, it's possible that one or two of the nozzle holes are completely blocked, which would increase the leakage oil losses from the pump, while the remaining holes still produce a decent spray. Can we draw any conclusions from this, or am I on the wrong track?

What about the discoloration, is that normal?

Could the nozzles be cleaned and restored to a usable condition, so that they could still be used as "spare parts," perhaps by soaking them in alcohol followed by ultrasonic cleaning, or are they beyond repair?

If many people are now writing that they still have the original injectors after 300,000 km - sorry, I don't want to take mine out .

Hi,

To be honest, my spark plugs, with 165,000 km on them, actually looked "new" compared to yours.
However, ESDs have little chance of fully discharging in my case, as they are driven frequently every day .

R.M. wrote:

He took the AU test three weeks ago and passed it very well; the values were well within the normal range. (But I did cheat a little, by adding plant oil and using a special Bosch mass airflow sensor ). Since there's a lack of performance, it's possible that one or two nozzle holes are completely blocked, which would increase the oil leakage from the pump, while the rest still atomizes properly. Can we conclude this, or am I on the wrong track?

It should probably fit. It's difficult to determine the atomization quality just by looking at the external condition; simply press the nozzles and see if the spray pattern is correct. If it is, then it's good.

However, there's probably already some wear and tear, as my fuel consumption has noticeably decreased since I installed the new nozzles.

Best regards, Rainer.

Quote:

To be honest, my spark plugs, with 165,000 km, actually looked "new" compared to yours. However, ESDs (Electrostatic Discharge) don't really have a chance to build up with me, as they are discharged every day.

So, I'm blaming it on city traffic.

Quote:

...because with my new nozzles, the fuel consumption has noticeably decreased.

I'm already looking forward to it .

Finally, there's the question of the brown discoloration – did you notice that as well?

Best regards, R. Mark.