Piston Burned: Causes and Solutions

Here's what happened to my 1Z. By chance, I was monitoring the oil temperature and other parameters when it happened to me at night.

Cooling water, 90 degrees.
Oil = 102 degrees.
So, nothing dramatic:

Does anyone have any ideas for me?

Is the 1Y engine block the same as the 1Z?

Hello,
This "error" doesn't happen in 10 minutes!
Best regards,
Günther

Excellent response, Günther. How about just not writing anything for a change, instead of all this constant rambling...?



Such damage occurs as a result of various problems. The coolant temperature reading and the oil temperature reading you are seeing are not representative of the actual conditions.
A possible cause is a faulty injector with a few holes that are too large, resulting in an incorrect spray pattern that reaches the piston. Alternatively, it might be dripping fuel in a way that the piston collides with the fuel stream. The piston cannot withstand this.
It would be interesting to know what the mileage is on the car. Are the original ESD components still installed?

I cannot tell you how comparable the 1Y and 1Z engines are. However, if you intend to use the pistons from one of them, I am certain that they are 100% different.

Regarding mileage:

Motor hat ca 150.000 km gelaufen. Alle bei mir. Immer brav mit Vollsynthetik und pflege bis zum übelsten Wie sich das halt gehört. Selbst vom 1. Tag an wurde er fast immer mittel Standheizung vorgeheizt. WIt's already bad enough.
Before installation, ALL seals, piston rings, and bearings were replaced with new ones.
The injectors were from the previous engine. They had approximately 40,000 miles on them, so now they have just under 200,000 miles.

He's had the tuning chip installed for approximately 50,000 kilometers. So, it's now at 100,000 kilometers with the chip. However, many of those kilometers were driven by my wife, who drives quite gently.

The plan was, if possible, to take the cylinder block from a 1Y engine. Because I am now going to disassemble it so that I can check the oil cooling system .

Thanks to both of you for getting this far.

@günther:

The car was in the Moselle region (300 km of highway each way) one week ago. It ran perfectly there.
Since I've been back, I've only driven 700 kilometers. I don't think that piston issue could have been a problem for very long, right? About how long does a process like that usually take?

200,000 km is quite a lot for injectors (although there are different opinions on that). I would only consider reusing these injectors after a thorough inspection. The injectors could be the cause of the problem.

If the chip tuner didn't know what he was doing, it's possible that he could only keep it running for as long as your wife did . In other words, bad chip tuning can damage the engine prematurely. Once it's running again, you can post some logs. The professionals here can then get a pretty good idea of how good or bad your tuning is.

It's also possible that a combination of both factors is at play. For example, the engine might have been able to last longer with tuned injectors, or the engine might have been able to tolerate the injectors better without any tuning.

Take a closer look at the pistons. Then, examine the spray pattern of the injectors. After that, you can decide whether to skip the tuning on the next engine or to check the injectors more frequently.

Other reasons are also possible, but these are the most obvious ones for now. I don't think the temperatures are a major issue.

It might be worth checking the piston cooling, although I suspect a faulty nozzle is more likely the cause of the melting debris (have the nozzles inspected).

Best regards, Rainer.

Hello, I agree with my predecessors.

A faulty nozzle was probably the cause of the problem.

A bad tuning?

Hmm... based on what I see in the pictures, definitely not yet.
If something was injected into one of the pistons, the other pistons would also likely have damage, or at least be affected.
However, the tuning must first be evaluated through a test drive.

With only one faulty piston and three that appear to be in good condition, a defective nozzle is highly likely.

Best regards, Jochen.

Hello,

TDI direct injection, 1Y swirl chamber (different pistons). Furthermore, MOST of the engine blocks in this series (1Y, AAZ) do not have a crankshaft sensor (except for the later models that already had electronically controlled injection control).
Otherwise, the drilling and lifting operations are the same.

Regards

AAZ with electric... what?

I don't believe that. At most, it might have a windshield wiper system, but otherwise, it has virtually nothing electrical except for the radio and starter.

m;

It was most likely a faulty injector. The damage pattern shows that the piston surface has melted, which only happens when the fuel stream directly hits the piston or when the injector is clogged to the point where it "drips."
With this type of defect, I wouldn't immediately blame the tuning. While an (excessively) long injection duration can certainly cause or contribute to this, there should be at least some "signs" on the other pistons as well.
Is the nozzle still intact? If so, have Bosch check it, then you'll know what the spray pattern looks like (if there's even one left...).