Mixing of Petrol in JB

[Guest alpha82]

Hi fellow Merc drivers,

I have an issue i'd like to highlight and consult.

Not long ago, my Check Engine Light (CEL) appeared. I checked online and it seems that most on the forums say it could be due to leakage in the exhaust system airflow for my model (Stock '05 W203 C180). It wasn't that huge a problem it seems. I went to my workshop to have it reset to have the CEL removed.

After that, it was alright for 2-3 weeks or so. During these 2-3 weeks, I've been to JB often and like all Singaporeans, re-fuel before I returned to Singapore. All alone, I've been on Caltex.

Then one day, the CEL appeared again for a day. I ignored it and then the very next day, it disappeared. Very weird...

It didn't appear anymore after another few weeks of normal and hard driving. During this period, I'm still on Caltex 97 from JB.

But 3 days ago, it appeared once more. This was after I entered JB and mixed 50% Caltex Techron 97 and 50% Shell V-power/RON 97 (Can't remember). The CEL appeared just a few minutes after i left the SG checkpoint. And until now, for 3 days, the CEL still appeared after starting the car and driving off.

Now usually i don't think mixing of fuel is too huge a problem as i've done it so many times before with no CEL and i think all fuel should be combusted in the combustion chamber.

But this time, i suspect that it might very well be the fuel mixture as before, no issues when on Caltex Techron 97.

Perhaps it's because Merc have so many sensors that any small differences, CEL will appear, as previously on my japanese honda car, i don't see such thing happening when i mix fuel in JB.

Can I check if any brothers here have the same experience or similar experiences with petrol and and the CEL? Because my friends didn't experience such thing on their Merc and BMWs.

Thanks in advance!

[Guest kepiting1sg]

alpha82 wrote:

Hi fellow Merc drivers,

I have an issue i'd like to highlight and consult.

Not long ago, my Check Engine Light (CEL) appeared. I checked online and it seems that most on the forums say it could be due to leakage in the exhaust system airflow for my model (Stock '05 W203 C180). It wasn't that huge a problem it seems. I went to my workshop to have it reset to have the CEL removed.

After that, it was alright for 2-3 weeks or so. During these 2-3 weeks, I've been to JB often and like all Singaporeans, re-fuel before I returned to Singapore. All alone, I've been on Caltex.

Then one day, the CEL appeared again for a day. I ignored it and then the very next day, it disappeared. Very weird...

It didn't appear anymore after another few weeks of normal and hard driving. During this period, I'm still on Caltex 97 from JB.

But 3 days ago, it appeared once more. This was after I entered JB and mixed 50% Caltex Techron 97 and 50% Shell V-power/RON 97 (Can't remember). The CEL appeared just a few minutes after i left the SG checkpoint. And until now, for 3 days, the CEL still appeared after starting the car and driving off.

Now usually i don't think mixing of fuel is too huge a problem as i've done it so many times before with no CEL and i think all fuel should be combusted in the combustion chamber.

But this time, i suspect that it might very well be the fuel mixture as before, no issues when on Caltex Techron 97.

Perhaps it's because Merc have so many sensors that any small differences, CEL will appear, as previously on my japanese honda car, i don't see such thing happening when i mix fuel in JB.

Can I check if any brothers here have the same experience or similar experiences with petrol and and the CEL? Because my friends didn't experience such thing on their Merc and BMWs.

Thanks in advance!

A quick check up by a workshop with the Engine Diagnostic will likely tell U what's the problem.

My previous 2004 W203 I got CEL because of water got into K-Box - changed K-Box problem solved.

Another time CEL came on. This time already de-kitted K-Box and left only stk car.

Went to MBM, told that engine oil got on to the engine cable and some MAP sensors are contaminated and faulty.

Was told that it's quite a "common problem" with some W203 C180.

No warranty and the repair bill comes to near $3K to replace engine cable, clean/replace MAP sensors & made mod to prevent future occurence.

My Rp 2 advice - go to a workshop equip with engine diagnostic and make a check what's the cause of your CEL.

[Guest alpha82]

Hi bro,

When I reset for the first time, it was done at this workshop with the OBD. At that time, the mechanic told me some leakage or air problem with the headers (or something like that). He advice that I bring it back to them for a good check to determine the source of the leakage. But after that, the light didn't come out for a few weeks, until i mixed the petrol...

If it's really the air problem, I believe the CEL will appear after just a few days of driving as the ECU will take a few days to register any anormalities, right?

[Guest Raskie]

becos it is intermittent, it makes troubleshooting more tedious ..

on my previous car, I had mine came on, stayed for the night's drive and the next day onwards, it did not come back ...

not sure if it could be the sensor is dirty ...