Tuning Chip Fails? Check Your MAF Sensor.

Hi there,

I had my 1.0L engine tuned with a chip, increasing the horsepower from 90 to 118.
However, the result is in no way discernible.
The car accelerates as usual, up to 160 km/h it's quite good, but then the power drops off significantly and it stops at 180 km/h and 3750 RPM – just like with a 90 horsepower engine.

The tuner confirmed to me again that he installed the correct software, which he has sold many times before.

He mentioned that my mass airflow sensor (MAF sensor) is showing an error code that cannot be cleared, and he suspects that's the issue. I've now replaced the MAF sensor, but the car is still performing the same way – both without the chip and with the new MAF sensor.

What could this possibly be? Has anyone ever experienced something like this before, or does anyone have any ideas?

Roadrunner505 wrote:

What could that possibly be?

A lot!

The answer might sound a bit silly, but without more specific information, no one can really help you, as our crystal ball is broken...

Is the mass airflow sensor error still active? Do you have any readings from VAG-COM? If so, then the situation is different, and we could definitely help you.

Otherwise, keep in mind: If a tuner messes with your car and you then experience problems (or no performance gain), keep bothering them until they fix it...

EDIT: Just to clarify, and it's not really relevant, but you didn't mention which vehicle the 1Z is used in...

Regards,
Guste.

Okay, then.
"It should definitely provide a bit more information, right?"

The 1Z engine is installed in a 1996 Passat 35i.

The error memory has not been cleared yet. I just wanted to know if that could possibly be related, now that the mass airflow sensor has been replaced...?

I mean, a faulty mass airflow sensor definitely reduces performance, that's clear.
"But after the chip swap, there wasn't even the slightest difference in performance."

I thought that maybe the performance would at least increase a little, or is it possible that the engine control unit (ECU) will limit the power so that it runs exactly like it does with 90 horsepower?

Otherwise, I would like to know what information someone needs in order to make a statement.

Thanks anyway - I still don't understand much about engines, but electrical stuff is my thing.

Roadrunner505 wrote:

The error memory has not been cleared yet. I just wanted to know if that could possibly be related, if the mass airflow sensor (MAF) was replaced...?

Yes, that's possible. The error can also be caused by a cable or contact problem, which wouldn't be resolved by replacing the mass airflow sensor.

Roadrunner505 wrote:

I mean, a faulty mass airflow sensor definitely reduces power, that's clear, but after the chip change, there wasn't ANY difference in performance at all. I thought that maybe the performance would at least increase a little, or is it possible that the lambda sensor (LMM) will slow down the program so much that it runs EXACTLY like it does with 90 horsepower?

It would be possible if the chip only increased the fuel injection amount when the maximum mass airflow (MAF) value is reached. If the MAF sensor doesn't report the maximum value... But I think that would be a strange chip.

Roadrunner505 wrote:

Otherwise, I would like to know what information someone needs in order to make a statement.

Please read the technical article "Methodical troubleshooting using VAG-COM." If you have any questions after reading it, please ask.

Roadrunner505 wrote:

Thank you anyway - I still don't understand much about engines, but electrical systems are my thing...

Don't worry about it, here are a few people from the electronics industry, including myself.

Regards,
Guste.