Z4M coupe Engine light on after running on 99 RON

T

tom21

Member
 Cheddar, UK
Hi Guys,

Looking for some help with my car if possible. I usually run the car on 97 RON super unleaded. The other day I stopped at tesco so thought I would try some 99 RON. Ran fine on the way back to my house. Went out in it last night and when I pulled out from my road I notice a distinct lack of power. Felt like it was cutting the power and there is an orange engine light on. Can anyone give me some pointers on what might have gone wrong or shal I take it to a local garage?

Car seems to run fine on small throttle input but when throttle is pushed further down it feels like the power is being cut.

Thanks
 
Doubt it's the fuel. I've stuck pretty much nothing but Tescos 99 in mine and the M3 (same engine) before that with no problems.
 
Had the same problem with mine. I just reset the fault and haven't had a problem since
 
A scan tool.

Anything obd2 will do

Or take it to a garage who would charge 30mins labour although takes 5mins to sort
 
But Taz, did you actually have this same issue? Did you lose power noticeably like the OP. From what I read the other day you just had the light on, no other noticeable problems...

Tom, you should definitely get the fault codes read and of course try to reset the fault, however I suspect it will keep reappearing. I think it is purely coincidental that you've used different fuel.

Eta: I've run my M on all sorts of 97/98/99 fuel and even once with 95 when I got caught out, never had any issues with any. Similarly the m3 I had before treated similarly never with any issues.
 
When I purchased my Zed six months ago I spent a fair bit of time reading up on issues via this Forum. There were definitly a number of members reporting problems with supermarket fuel and dashboard lights coming on which were resolved when going back to premium grade fuel. It was something to do with the additives not added in cheaper fuels and possibly higher levels of Ethanol in supermarket petrol.
If you do a search you should be able to find the thread. It may just be a coincidence with your car but I would definitly go with adding some super quality petrol asap before looking at anything else.
 
tom21 said:
Thanks for the advice. Ill book it in with a local BMW specialist.
Click to expand...

Buy yourself an OBD cable of some kind - it will pay for itself twice over paying someone to fault read once.
 
Taz said:
Had the same problem with mine. I just reset the fault and haven't had a problem since
Click to expand...

You didn't feel a lack of power though :? certainly didn't struggle making "85" while the light was on :oops:
 
TomK said:
But Taz, did you actually have this same issue? Did you lose power noticeably like the OP. From what I read the other day you just had the light on, no other noticeable problems...
Click to expand...


oops missed the bit about losing power, no my car was fine no loss of power at all
 
I have got a scanner if you want to reset it im in the new forest at the moment so dont mind taking a drive out
on sunday if you want to get the codes and do a reset
 
mr wilks said:
Taz said:
Had the same problem with mine. I just reset the fault and haven't had a problem since
Click to expand...

You didn't feel a lack of power though :? certainly didn't struggle making "85" while the light was on :oops:
Click to expand...

These lights do like to come on after changing fuel types/brands. I had it happen to me when I had to put Esso in.

I don't think supermarket fuel is any more likely to make it happen, but as we know the ECU adapts, so I'm guessing a sudden shock shall we say may cause it to happen.
 
I almost exclusively use tesco 99 fuel in my M3.

Plug it into a pc, read fault codes and then reset the engine adaptations and fault codes

Also look into what the fault codes mean as it could be a coincidence.
 
There is also a throttle pedal fly-by-wire manual reset which you can do manually. It involves turning the key to "contact" / ignition position leaving for 40 specs etc. Google it or search function on the forum. TBH it could just be your MAFF is KO and the new fuel just coincided. ECU then just put the car into safe mode limiting the power.

Otherwise, to me it would seem logical for the car not to be 100% settled engine wise when you're changing its feeding habits (changing air intake, height octane etc. The ECU may need a little time to adapt. I had this after the Gruppe M install and it lasted a couple of miles and switching the car on and off.
 
A M specialist has had the car since last tuesday and they still seem none the wiser, they found some fault codes. 2 regarding fuel mixture and 1 regarding airflow sensor. They want to order a new maf sensor as the next step but im thinking I might just get the car back off them and troublshoot myself. MAF sensor from Bosch is looking like £190. Seems alot of money for guess work.

They also said that they took the car out once and there was no engine light or throttle hesitation. Then when the started it up again the next day the light was back on
 
Air mass is common,

Do you have the standard air filter ?

Fuel mixture or "trim" is a hard one to find,usually its air leak or Air mass that the culprit though...
 
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