1Z Still Not Working: Troubleshooting Guide

Hello,

My Volkswagen Golf 3 1Z still isn't reaching its maximum speed.
I posted something last year and received some helpful tips.

I tried the following:

Ulf ventilation test: approximately 1 second too slow (this might also be due to calculation errors, as I don't know the exact weight and have only estimated it).
'Lmm swapped.'
Diesel filter replaced.
The lines from the filter to the engine have been replaced, and now there are no more air bubbles.
Error memory is empty.
Air filter replaced (sports air filter).
This magnetic valve, which is located on the passenger side fender, has been replaced.

I thought maybe using winter diesel would make it go a little faster, but according to the speedometer, it's doing about 180 km/h (172 km/h according to GPS), but it feels very sluggish, and that's only when I'm driving alone. It accelerates properly up to 160 km/h.

Regarding the acceleration, I think it's perfectly fine. A friend of mine with a Golf that has a 1Z engine accelerates from traffic lights at roughly the same speed/pace.
'Sometimes, when shifting from first to second gear, there's a brief squeaking sound. However, there is plenty of torque (I have 185-size summer tires).'

What else can I try?

Should I stop using it?
Can Kat be temporarily disassembled for testing purposes?

Thank you in advance for any advice.

Sure, here's the translation:

'One more question coming up:'

While driving home, I was just now able to enjoy riding in the slipstream of a T4. YAYYYYY! It's going over 190 km/h on the speedometer, but only while in the slipstream .

What I noticed was that sparks were flying from my rear window, not many, but they were clearly visible when no one was behind me.
Where do they come from? Isn't that unusual?

'Furthermore, my engine always sounds very smooth after about 30 minutes of driving on the highway. There's no more knocking sound, and it's barely noticeable even when idling.'

If he manages to achieve a score of 190-200 on his own now, I would be really satisfied.


Here's one more addition:

Whether I press the accelerator pedal all the way down or only two-thirds of the way, it doesn't seem to matter. Does this mean that my engine receives the same amount of diesel fuel at two-thirds throttle as it does with full acceleration, or does the difference simply not result in any additional power?

Hi.

Currently, there is a technical article available about finding the lost performance using VAGCOM.

Please work through this "little bit" for now, and then we can see what happens next .

Okay, I found the article. Thank you.
However, I don't have a working adapter at the moment.
I somehow lose connection with him/her.

G3TDI wrote:

Thank you, I found the article. However, I don't have a working adapter at the moment. I somehow lose the connection with him.

Hi.

What is the manufacturing year of your car, and which adapter are you using?

My car was manufactured in the latter half of 1995.
The adapter is homemade; instructions for building it were once linked on this website.
Definitely one with an optocoupler.

G3TDI wrote:

My car was manufactured in the latter part of 1995. The adapter is homemade; instructions for building it were once linked on this website. Definitely one with an optocoupler

.

Hi.

That must have been one of my earlier drafts.

Currently, there are improved circuits available here, as well as tips for older problem adapters --> diagnostic technical articles .