VersaTune User Forum

Hi, I own a '08 Mazdaspeed 3 (or Mazda 3 MPS) which had a brocken engine a few months ago. I completely built a new engine which now has run almost 1100km now. Now it's time to put some load (not 100%, but more than the last 1000km) to the engine. Doing that, moderate accelerate from about 2000 to 4500 rpm with 50% pedal position or so rusults in a rough or uneven acceleration. It feels like the boost comes up, and goes away, and it comes up...

It's all stock, except of a closed EGR. My plan was to reinstall Versatuner, after the engine works fine again. I've attached some logs - cause I have no clue what is going wrong. The Turbocharger is also new, the Injectors were checked and cleaned.

Any Ideas? Thanks!!!

Export the logs on CSV and then post them here.
It sounds like the boost control part is acting weird or doesn't work correctly.

ok, so I checked the second log and it looks like you're getting fuel cut but we don't know why yet. Please post some better logs as well as your tune.
Log the following:
abs load
frp
relative throttle position
MAF airflow
ignition timing
Knock retard
MAP
Boosted air temperature
Actual AFR
LTFT

Just log until you reproduce the problem and try to keep the acceleration pedal pressed even during the event occurrence. Try to log a few seconds before and after, not full minutes, so that we can easily identify the relevant log lines.

Thanks for your answers. I am currently drive the stock tune as I am running in my new engine.

However, I installed new NGK spark plugs with the new engine and one of them seems to have a broken ceramic part. After changing that it is much better now.
I'll come back to that (and post better logs when needed) when I can put higher loads to my engine. Thanks for your support!

You can still log with versatuner even with the stock tune or even before installing versatuner on your car.
If one of the plugs had a broken ceramic insulator I strongly recommend to clean that cylinder and inspect it for scratches. A broken plug can lead to a lot of other problems.

Hi, I have logged already with stock tune, the logs in my first post where logged with stock tune aswell.

There is no need to clean that cylinder. It was more a scratch or so - all parts of the sparkplug are still there, but the ceramic part (outside of the engine) has scratches, but enough to have no isolation.
I've attached a picture.