AJM Performance Issues: Troubleshooting Guide

Hello everyone.

As a 'newcomer' here, I naturally have a question about what is probably a somewhat larger issue:

'My AJM engine, with 85 kW and 285 Nm of torque, is causing me concern. When I'm driving at a constant speed of around 2000-2500 RPM and then accelerate, there's a brief jerk before it picks up power. Sometimes this jerk is very pronounced, but other times it's only minimal and barely noticeable. I then deactivated the EGR system, and the jerking stopped. So, the EGR valve was replaced, but unfortunately, it didn't solve the problem. Additionally, the mass airflow sensor (MAF), turbocharger pressure, fuel filter, air filter, etc., were checked, and everything seems to be in order.'
'The Friendly' is at a loss and couldn't help me either.
Okay, here's another problem that might be related: The Passat has a chip tune and was also tested on a dynamometer. The original power output was 95 kW with 270 Nm of torque. After the tuning, it's 106 kW with 310 Nm. So far, so good, but the tuner was a bit surprised that the torque was 'so low.' Usually, it should be around 350 Nm. Repeated checks of the data and further fine-tuning didn't yield any improvement. He was also a bit puzzled by it.

I hope someone here can help me. I've been browsing this excellent forum for a while now, and I'm often amazed by the wealth of knowledge available here.

Thank you very much in advance.
T. H.

Note: The turbocharger and the wastegate valve are also new.

Hi,

It is well known that a lot of nonsense is often measured on social media.

As a control test, please perform the acceleration test from 2000 to 4000 rpm in 3rd gear.

If you enter the target values for the tuning into the DZR (Dynamic Resonance Analyzer), you will see approximate times in the calculation rows, indicating how long the engine should take for each 200 RPM increment.

If you log the driving test with VAGCOM, you will get a chronological record of the increase in engine speed.
By comparing the results with the DZR calculation, it should be possible to determine from the baseline performance whether the engine is underperforming compared to the target tuning values in the range of 2000 rpm.

Further insights can be gained by logging the injection quantity, limits, or the calculated torque.
If this indicates that the target torque is being reached, but the engine still feels weak, you likely have a hardware problem that is not being detected by the EDC sensors (e.g., a fuel supply issue).