1Z Performance Gap: Analysis & Solutions

Hello everyone,

I know we've discussed this issue many times. There's a drop in performance at speeds of 100-120 km/h, but before that, the performance is normal.

I started by reading the error codes.

-00575
-00668

Okay, so... it sounds terrible at first.

In addition to these values, please note any irregularities.

- Does the VAG diagnostic tool not display the 4th cylinder?
- at 3/3, 450mg/h at idle.
- At idle (4/2), -1.7 degrees.
- Under 4/2 full load, 8 degrees.
- Below 4/3 idle speed: -1.0 degrees.
- Below 4/3 load, 8 degrees.
- Below 10/3 full load: 2083 mbar.

'The air mass seems too high... something strange is going on. The fuel injection timing is at a negative crank angle (BTDC)? Also, the boost pressure under full load is much too high, which is likely causing the 000575 error code and the resulting power loss due to fuel injection quantity reduction.'

The hoses aren't 100% reliable anymore. I've had hose problems with the control unit before. I cut off the worn end and reattached it, and it worked again.

Where's the best place for me to start with all this fun?

How can I use VAGCOM diagnostic data to narrow down or rule out specific issues?


Please provide the German text you would like me to translate into English.

96'1 Z, 170,000 km, Automatic.

Hi !!

You're twisting things around quite a bit.

The air mass is not "too high"; the 1Z value is never quite regulated as desired, even when idling (at least, I don't know anyone who can achieve it).

Furthermore, the airflow at full load is noteworthy.


"00575 is a turbocharger pressure error, and it definitely doesn't originate from any kind of fuel injection issues."

In Block 4, vaccinations are starting - no operating rooms!
There is only one OT.

-1 means that the injection occurs 1 degree *after* Top Dead Center (TDC).

Since the injection start control is obviously working, we don't need to consider it further.

The boost pressure is too high (as indicated by error code 00575).

Please log the values for blocks 003-008-011 at full load, with engine speeds between 1500 and 4000 RPM in 3rd gear, and create a graph from the data.

Then we can say something – but individual values alone won't get us anywhere.

It should look something like this:
http://mitglied.lycos.de/Estetal/gifs/Golftest.jpg

m;

Yes... the confusion is spreading.

'But the start of injection timing can't be right like that, can it?'

I will send you the values later... although a full load measurement might be difficult to perform automatically, especially starting at an engine speed of 1500 RPM (kickdown).

I'm doing my best, let's see what Excel comes up with. If Vagscope doesn't record anything useful (I'm a beginner with Vagcom), then...

But thank you in advance.

kapselchrissi wrote:

"But the start of injection timing can't be right like that, can it?"

Why not:

Quote:

- under 4/2 idle -1.7 degrees. - Under 4/2 full load, 8 degrees. - Below 4/3 idle speed: -1.0 degrees. - under 4/3 full load, 8 degrees

You have a target idle value of -1.7 and an actual idle value of -1.
At full load, the target value is 8, and the actual value is 8.

That fits perfectly... What's the problem?

"A 0.7-degree deviation at idle is a perfect result for an old 1Z engine; mine is way off at idle! As you can see at the beginning and end:"

carefully selected and painstakingly created a graphic.

A new error has also occurred: 519.

It's likely that the 519 error code appeared because I checked the hose connected to the control unit, and it may have developed a leak in the process. Okay, I'll check that again, but I don't think that's the only problem, because the entire system was already malfunctioning before the 519 error code appeared.

Unfortunately, you omitted an important piece of information regarding the boost pressure: the valve travel ratio of the control valve.

This can reveal whether and what the electronics are doing to try to prevent excessive charging surges.

m;

I hope you're referring to the testing behavior of the charge pressure control valve (11/3).

is in the D3 graph (the top one).

I created several graphics to account for the scaling.

Assuming target values of 40-70 percent, it reaches 94.1 percent at full load in the peak range (if I'm interpreting that correctly).

I just checked the hose leading to the control unit and made sure it's not blocked. Everything seems to be sealed properly, but the test drive didn't improve the situation.

What is that doing there?

If so, then we need a diagram showing all 4 values from 011.

Then you can see the reaction of the electronics. The key presses in the first diagram are displayed randomly and do not correspond to the boost pressure diagram at all.

All values/diagrams are from the same test series.

In the graphic below, you'll find measurement block 11 again (test behavior of the turbocharger boost control valve, multiplied by 10).

OK.

That part does such strange things that I couldn't imagine that they belonged together.

Are you sure that all the tax cables are correctly connected, leak-proof, and have continuity?

The current boost pressure reading appears "capped," which suggests the sensor may have reached its limit and can no longer measure further. However, the actual boost pressure might be even higher – in which case, your turbocharger is likely to fail soon.

The part generates far too much boost pressure, and the electronics are unable to compensate for it.

Please check all the colored (red, blue, black) hoses very carefully.
Possibly, you can attach a syringe to the blue hose and push. With some force, the rod (marked in green in the image) should move. This rod opens the wastegate, preventing the boost pressure from becoming too high.

Perhaps the membrane is torn in your system, and the control pressure is unable to have any effect.

m;

Okay, as far as I can tell, the blue hose connects to the can. I had to use a bicycle pump to apply pressure, and with some force, it moved a millimeter with a creaking sound. Could it be the can, even though the rod seems to move under strong pressure? How do I fix this thing?

What about the magnetic switch valve? Can it be tested? What voltage should be present at the connector (ignition on/engine on)?

The remaining hoses appear to be in good condition.

The solenoid valve is pulsed, meaning it is repeatedly turned on and off, approximately 2 times per second.

When the motor is running, there should be a noticeable and possibly audible ticking sound.

Now, let's talk about the wastegate:

The rod in my picture has a joint. If you remove the retaining ring there, you can check if the pressure chamber is stuck (it should still move smoothly without any squeaking) or if the wastegate is seized.
It's also possible that the joint is stiff.

Unfortunately, I don't know if the whole thing will work when installed, where you can get the individual parts, or how much they cost.


In my case, I was able to open and close the wastegate nicely with the syringe, even just partially, precisely as I applied pressure. (However, I also had the turbo loose in my hand.)



m;

'All I hear from the solenoid valve is a kind of hissing sound (I listened to it directly). There are no clicking sounds... and there's no change whether the connector is plugged in or unplugged.'

Before I buy the valve, what voltage should be present at the connector (due to a possible broken wire)?

Perhaps that's the problem, and I can avoid having to expand the pressure vessel.

The valve is being pulsed with 12 volts.

costs 30 EUR.

Okay, power is on.

I used spray lubricant to make the rods move smoothly again. They now move freely and return to their original position.

I'm going to VW tomorrow morning to buy a new solenoid valve.

Sure, here's the translation:

'Please translate the following text from German to English. Provide only the translation, no explanations. Then, tell me how Golfi is doing.'

Thank you very much in advance .