i have a problem with my 2014 M3.
i was driving along a main road @30mph when there was a noise and a notice of "engine management fault" on the dash. I
managed to get it home, and the next day called out the AA. The guy couldn't find a fault, but did it the old-fashioned way of checking for spark, then petrol to the engine.
gaave up in the end, advising me to take it too my garage, they did tow it there OK.
Since then the mechanical engineer told me ho couldn't find a fault either. Got an auto-election to check, again - no joy.
he concluded it might be the ECU, and said he could send it to a specialist, which I said was OK (am in their hands).
I appreciate no one here can tell me the problem.
I just wanted to know if anyone has had a similar problem on their M3 that may be able to help, please?

 

Wow! So many armatures checking your Mazda.
So, the way I am reading this is you drove home? If that is the case the ECU placed the engine operations into safe mode to protect it from what ever happened?
The ECU was not properly scanned! Nor by your post checked completely
If the engine check light was activated, then even if the ECU was bad, you would be able to at least communicate with the ECU unless it failed in which case you would likely not eve see the check engine light. A
The ECU was not checked for state of its health?
The environment where the ECU is located can have a good idea if the ECU was damaged by for the most part its environment?
Nothing was mentioned about checking the battery (load test it before any electrical diagnosing should be done 1st) for its current state of health.
Then check the connection to the ECU. Harnes for good contact and clean terminal connectors.


I am not sure how asking if other have had the same problem unless you are referring to people checking your Mazda that have no clue how to do it?

You should be having your Mazda looked at by a person that is actually educated and specifically trained and has some form or certification (hopefully current and not something from the 90's or older) in automotive diagnostics for the OBDII and CANbus operating systems and not just an average mechanic!

This is the best answers, guessing at things and suggestions I can give based on the limited and poor information because of the people that initially worked on your Mazda.

 

thank you, Callisto for the reply, very informative. .

Yes, the AA guy did check the battery etc.
I'm sorry, that's all I can add to your interesting post, I'm not a mechanic.
the guy did say he knew of a place where they check /repair ECUs, so he has sent it off to them, it could take a week to get it back (If indeed it comes back)
Luckily we have the wife's Mazda 2 to use for now.

It's a minefield with me not knowing much about How ECUs control everything, I'm old school afraid, just a toolbox of Spanners & screwdrivers etc

 

Oh Ok. I would have asked a bit more whom or what the service is that looks at the ECU? I would hate to tell you how most that advertise serving them what they do? But we will wait and see what the result was? In the mean time I suggest you look into vendors that offer rebuilt ECU with a short-term warranty.
As for "old School" trust me that is how I was born, and it took constant schooling to stay updated with technology. I resisted electronic fuel injection and dumping point and condenser ignition for the longest time. And a computer that controlled the engine and transmission no way was I going to ever have a car that was run like that. LOL Now I program ECU's would not ever think of having a carbureted engine again, although I go into dream land and will follow a Muscle car just to smell the exhaust. LOL

 

Yes, I realise how good you are with technology, after reading some of your answers to other forum members.
Well, I copied your first reply to the garage I left it with, and the owner (Nic) replied to my mail that he did do all the tests that you advised.
I can't ask him for proof etc, so have left it with him, in the hope it can indeed be rectified
I looked online for used and found this one at @£50, .......

https://www.ebay.co.uk/itm/166243942...3A1%3Bchoc%3A2
Would that suffice for my 2014 M3 SLnav, do you think?

haven't heard back yet though.

 

LOL thank you for the trust and taking my suggestions.

I can tell you that in the Auto mechanics world there is LARGE ego's. I mean BIG EGO's. Especially with males. They all think that if at one time they turned a wrench they are a bonified mechanic. I generally tell people I help to suggest that they acquired the informatio9n by researching instead of someone like myself. This way shop is at least a little more open minded. My guess is that he liked the list of things to check and because you left the Mazda with him with that list I am willing to bet he is now looking at perhaps testing a few that was.... shall we say forgotten and over looked? LOL
Mechanic should be like a Medical practice, unless you stay up to date and constantly acquire new certification you should just stop practicing. Maybe that's why they call it practicing regarding patients. hmmm maybe that is the same in the auto service world they "practice" learning on their customers vehicles. LOL

Ok enough of that fun!


The picture and information about the ECU "looks" to be correct... however even I will contact the supplier with the vehcle information to have them confirm the correct ECU/PCM or TCM.
I give them the following information
Make
Model
Year
VIN (most important)
ECU part number
ECU serial number
model number if lists
Basically anything number information on the ECU. Even a snap shot of it/

Let them state the one you buy is the correct one! This way you are protected should it actually end up being the wrong one. Do Not send in your CORE until the ECU is installed and the Mazda starts and runs and then no engine check light and not indications in the ECU via scanning the area's i will list for you. Hopeful the shop does the same?

Current DTC
Pending DTC
Permanant DTC
State of I/M Monitors
Once the ECU is cleared and the I/M monitors reset you should drive for about 3 days and then have the ECU scanned again for all those areas. Nothing should be found and I/M monitors should be in green or what is called state of readiness.

 

Im back after a long worry and payout.
The guy (mechanic) I took it to has done a load of things (over the 2 months he's had it) to which has cost me an arm & a leg, and still not working.
After all that I spoke to a different Mechanic who has been in the trade for Donky's years (yes he is in his 70's)
He reckons it might be the timing Chain has slipped a couple of cogs on the wheel, causing it to misfire etc.
That sounds feasible to me if it's not running top dead centre.
he said he'd have a look at it. So does this sound like a reasonable fix maybe?
Thanks for any time
Bob

 

Well...... really age does not necessarily mean experience....LOL really!

and if he was then his theory using and old school timing light could confirm that guess. But given the year of your Mazda is highly doubtful that his guess is correct!

 

Right, I've just got back from the guy, and he has taken the (rocker box?) off, showqinf the timing chain, which doesn't appear to be too loose, he thinks htat it might not now be the problem.
He has taken the power packs and spark plugs out, only to find them covered in oil, which is why the first guy said there was black smoke coming from the exhaust.
So far so good (maybe)he's now awaiting a new compression tester (on order) to carry this out.
hope you're with me so far lol.
Just waiting for another call now, be tomorrow with good news I hope.

 

I keep reading your info...... I hope they are making these experiments to find you problem notated on your service order?
BTW coils (you or they call them power packs) will fire just fine saturated in oil even and the possibility of causing the engine to increase exhaust smoke would be something magical.