Rough or "uneven" acceleration

Discussion of tuning specific to MAZDASPEED3/MAZDASPEED Axela/Mazda 3 MPS vehicles
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Abovuekt
Posts: 3
Joined: September 1st, 2013, 9:06 am

Rough or "uneven" acceleration

Post by Abovuekt »

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!!!
VersaTuner Logs.zip
(39.39 KiB) Downloaded 629 times
mituc
VersaTuner guru
Posts: 1324
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Rough or "uneven" acceleration

Post by mituc »

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.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
mituc
VersaTuner guru
Posts: 1324
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Rough or "uneven" acceleration

Post by mituc »

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.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
Abovuekt
Posts: 3
Joined: September 1st, 2013, 9:06 am

Re: Rough or "uneven" acceleration

Post by Abovuekt »

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!
mituc
VersaTuner guru
Posts: 1324
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Rough or "uneven" acceleration

Post by mituc »

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.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~509BHP @34PSI
2008 Icy Blue Mazda CX7
Stock engine and exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 330-ish BHP
Abovuekt
Posts: 3
Joined: September 1st, 2013, 9:06 am

Re: Rough or "uneven" acceleration

Post by Abovuekt »

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.
Attachments
WP_20130903_006.jpg
WP_20130903_006.jpg (105.35 KiB) Viewed 14059 times
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