vibrations at a stoplight

Mazda 2 2008 drops from 750 RPM to 550 RPM when stopping in Drive and pressing the brake, causing the car to shake.

I have already replaced the upper right engine mount, but the issue persists. I also tried cleaning and replacing the throttle body, but the car still vibrates.

Someone told me that this RPM drop is normal and that it's a fuel-saving feature in Mazda. Is this true?

What can I do to fix the vibrations at a stoplight?

 

My wife's 2011 Mazda 2 has rough idle also. I replaced the engine mounts, which helped a bit, but it still has a fairly rough idle. You could try resetting the ECU.

 

maybe you meant something different….technically speaking you can not “re-set” a factory ECU. You can have a shop or the dealer do an update or a pass-through of the last or original programming “”flash” but that is not what is causeing engine vibration issues.
Doing a comprehensive ECU scan will have some direction as to the cause and if not then either have a diagnostic done using an oscilloscope or a mechanical compression test and leak-down test to check the state of mechanical health of the engine.

 

I just meant disconnecting the battery for a while so the ECU forgets anything it has 'learnt'. It's probably not technically a reset, but it is broadly referred to as resetting the ECU across the internet and is the advice that was provided to me when I was delving into the rough idle issue. The article below is an example.

https://www.ancel.com/blogs/news/res...ctory-settings

I don't know whether it actually causes the ECU to forget any learnt settings, or whether it assists with the car learning to idle at a higher rpm, but that's what many people claim it does.

 

That is a misconception with at least most ECU from about 2002 to present. The internet is friendly for those that don't understand and like to find things they think are fact based. When you disconnect the power supply to the ECU it will turn off the check engine light but what caused that light remains in the permanent file until the issue registered no fault with the sensor input relating to the original issue. You can also see not only that in the ECU DTC permanent file area but when your actually drive several drive cycles to re set and reestablish the I/M monitors that you have now placed all of them in fault by you disconnect the battery in the end making it lengthier to diagnose the cause of an issue!

As for the other misconception of "ADAPTIVE" ECU qualities, in a nutshell the ECU is for a simple term constantly reconfiguring the output to adjust for Dailey driving so from a loose description is constantly adapting. You can't go out and do an "Italian-Tune- up" and then claim the engine runs differently because the WOT was already "adapted" for driving technique. In other words, we have not reach AI capabilities yet in a standard ECU to over think how a driver is controlling the throttle and braking.

Your internet surfing just an FYI look at the author and to the authors credentials. Or the company that is placing the article. hmm you think they want to sell you their product? lol > * About Us | ANCEL That one you posted not only has no author but not one person on their staff is an ECU/EFI Calibrator. Nor do they indicate any experience in understanding how an ECU/PCM or TCM OEM programing is engineered and how the basic ECU really works. Next time spend a little more time and find evidence to support your thoughts and beliefs a little more time.


If it were only that simple as that article and many like it were then I would not be spending countless hours Calibrating ECU for my customers for their changing Enviromental and track or public roads use!!. And the dozens of performance ECU Calibration companies would be out of business.

Here is a short few second data logging from a customer's car, do you see the CELL that is for ADAPTIVEs? lol
You can also go on line and contact any company offering ECU [programs and ask them about adaptive. For Mazda I suggest Versa Tuner

[url]https://www.youtube.com/watch?v=bm_UaP-XHyk]20160524 075902


The question I always suggest that someone on any platform forum post an example like your or comments I ask them to please find on the internet any information empirical and factual that shows where in a ECU is the area that makes adaptive globally? Have fun with that!

The fact is your ECU is constantly adapting to sensor input as well driver input.

 

Some more info would help….
Tomey 2008 Mazda 2 Auto, when stopping in Drive?
=>> is it a 1.5lt? How many kms on the car?

J0NS 2011 Mazda 2?
=>> Is it Auto?, Is it a 1.5lt? How many kms on the car?

For both of you….
[1] If you shift from D with it vibrating into N with foot on brake, with A/C & Headlights Off does it return to standard idle
or
If you shift from D with it vibrating into N & pull on the "Hand Park Brake" & then take your foot off the brake, with A/C & Headlights Off does it return to standard idle

[2] Is the rough Idle when stopped at Traffic Lights in “D” more prevalent on days of high relative humidity? or at particular outside ambient temperatures?
[3] Is this a just/only/most commonly a full Op Temp Idle issue when stopped in “D” at the Traffic Lights with all accessories off (ie no Idle Up function enabled by the Head Lights, Ventilation fans or A/C etc)?
[4] Does the vibration also happen when the radiator thermostatic Fans Cut in ie 100 Deg C ECT Temp?

If you turn on the:
[6] Internal Cabin Fan does it return to standard idle (ie Idle Up enacted)
[7] A/C & Internal Cabin Fan does it return to standard idle (ie Idle Up enacted)

Turn Off the Cabin Fan & AC

If you turn on the:
[8] Head Lights does it return to standard idle (ie Idle Up enacted)
[9] Head Lights & set HI Beam does it return to standard idle (ie Idle Up enacted)


##########
Tomey WRT:
“Someone told me that this RPM drop is normal and that it's a fuel-saving feature in Mazda. Is this true?
=>> NO.

“What can I do to fix the vibrations at a stoplight?”
=>> If you place the car into “N” when stopped at traffic lights does the vibration stop & the RPM stabilise back to 750RPM?


##########
Consider:
https://www.mazdaforum.com/forum/maz...leaning-53404/
Are your LTFT% & STFT% reasonable?

If you follow this procedure:
engine_tune_up-1077.html

What is the Full OpTemp Idle OBD2 PID for:
a) TP%?
b) MAF?

If the MAZDA2 1.5lt throttle body is clean & the ECU various Input Sensors are all clean & functional/in good condition running 91RON at STP expect
MAF(g/s): 1.50
TP(%): 10.5/10.6


##########
Its hard to diagnose a car with limited information, no service history & no OBD2 PIDS over the internet……

However, if you have Cleaned the Throttle Body, MAF, IAT & the car is otherwise in good well serviced Mechanical Condition with no OBD2 pending codes…..Replacing the Inlet Manifold Gasket is something to consider.
The Inlet Manifold is Plastic & the Head is Alloy, just like other cars of more than 12years of age the “Inlet Manifold Gaskets go hard, flat & lose their elasticity and ability to ensure an effective seal over the operational temperature range”, just like cam cover gaskets & sparkplug tube seals, the Inlet Manifold Gaskets also require replacement (Silicon performs better than EPDM as “15yrold Gasket Material” but nothing lasts forever).
Based on experience I suspect that changing the 1.5lt Inlet Manifold Gasket will assist with stabilising the hot idle.

##########
I’ll get some popcorn now.

Rob

 

Rob sorry no pop corn needed. Honestly your response is to long not really helpful for an Auto Tech and the source you quote for some suggestions and information is IMHO nothing more than another DIY

For me it's simple you have to go back to basic's and the first thing is to scan the ECU in all 3 areas first. The monitors are very important to check
The engine check light and pending DTC is only a starting point to alert that there is an unresolved issue and the ECU is activating the check engine light.

 

Then you should have gone to a service center and had it looked at the first and definitely the second time it happened.
These off the cuff threads about issues generally turn out not to be a common or commonly reported problem with Mazda for your year and model etc.. What I found is many times its customers thinking something is wrong and it ends up being there driving habits. Not saying that yours is but ....

Lastly if you are going to respond to a thread when it is asked if other experience the same thing it really is a good idea and practice to post your specific Mazda information like year, engine size and miles. Also the last date of any service and what exactly it was. These have a great determining influence if your Mazda does actually have the same occurrence as the OPs in this thread or any thread asking the same as questions.
From this point if anyone that has experience will then ask operating conditions that caused the claimed like issue ?