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Discussion Starter · #1 ·
Hi there,

So I just purchased a manual Cooper S R56 2010 with only 28,000km on the clock. Mileage was verified and overall state of the car is coherent. Went for a oil and oil filter as well as air filter change as soon as I got the car.

  • Starts like a charm even when cold
  • Misfire under heavy laod
  • Kind of slow compared to my ex 07 R56S (auto)
  • Hesitation/ sluggish behavior under 3,000rpm
  • Excessive backfires
  • Fan on as soon as car starts (even if it stayed overnight) and hood of my car isn’t hot after driving (my ex’s hood burned me a few times)

No CEL at all, code reader suggests thermostat is failing.Changed the spark plugs and misfiring under load is gone yay! Today im left with low rpm hesitation and excessive backfires.

Thermostat, water pipe, expansion tank arrived today, will install them on Sunday before getting more serious (fuel filter, tank pump).

Do you think the thermostat can mess with the engine and cause these symptoms?
Any ideas where these issues may come from?

I know the car was used to run errands or weekends sometimes; i’m sure it never had a walnut blast
 

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yes thermo can mess with it,
 
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Hi there,

So I just purchased a manual Cooper S R56 2010 with only 28,000km on the clock. Mileage was verified and overall state of the car is coherent. Went for a oil and oil filter as well as air filter change as soon as I got the car.

  • Starts like a charm even when cold
  • Misfire under heavy laod
  • Kind of slow compared to my ex 07 R56S (auto)
  • Hesitation/ sluggish behavior under 3,000rpm
  • Excessive backfires
  • Fan on as soon as car starts (even if it stayed overnight) and hood of my car isn’t hot after driving (my ex’s hood burned me a few times)

No CEL at all, code reader suggests thermostat is failing.Changed the spark plugs and misfiring under load is gone yay! Today im left with low rpm hesitation and excessive backfires.

Thermostat, water pipe, expansion tank arrived today, will install them on Sunday before getting more serious (fuel filter, tank pump).

Do you think the thermostat can mess with the engine and cause these symptoms?
Any ideas where these issues may come from?

I know the car was used to run errands or weekends sometimes; i’m sure it never had a walnut blast
Hi there,

So I just purchased a manual Cooper S R56 2010 with only 28,000km on the clock. Mileage was verified and overall state of the car is coherent. Went for a oil and oil filter as well as air filter change as soon as I got the car.

  • Starts like a charm even when cold
  • Misfire under heavy laod
  • Kind of slow compared to my ex 07 R56S (auto)
  • Hesitation/ sluggish behavior under 3,000rpm
  • Excessive backfires
  • Fan on as soon as car starts (even if it stayed overnight) and hood of my car isn’t hot after driving (my ex’s hood burned me a few times)

No CEL at all, code reader suggests thermostat is failing.Changed the spark plugs and misfiring under load is gone yay! Today im left with low rpm hesitation and excessive backfires.

Thermostat, water pipe, expansion tank arrived today, will install them on Sunday before getting more serious (fuel filter, tank pump).

Do you think the thermostat can mess with the engine and cause these symptoms?
Any ideas where these issues may come from?

I know the car was used to run errands or weekends sometimes; i’m sure it never had a walnut blast

Same on my 14 roadster! I have been chasing this for 3 months. I thought it was bad gas. FINALLY threw the code P0100, Mass Air Flow censor. I am going to clean it the weekend. I'll l will let you know.
Bob
 

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OK... I cleaned both sensor's. Still missing and backfires. Now it has a P0300 code. I replaced my coils and plugs when this first started. I did put a bottle of HEET in it. It takes water out of the gas. We'll see.
Bob
 

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Discussion Starter · #6 ·
OK... I cleaned both sensor's. Still missing and backfires. Now it has a P0300 code. I replaced my coils and plugs when this first started. I did put a bottle of HEET in it. It takes water out of the gas. We'll see.
Bob
Went to the dealer and they didn’t have time to get my parts from inventory LOL! So thermostat will have to wait Monday.. i’ll update you on the results!

I am thinking about my transmission too; may be the reason behind the low power issue
 

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Discussion Starter · #7 ·
OK... I cleaned both sensor's. Still missing and backfires. Now it has a P0300 code. I replaced my coils and plugs when this first started. I did put a bottle of HEET in it. It takes water out of the gas. We'll see.
Bob
Random/multiple cylinder misfire, try making sure you plugged everything correctly and/or didn’t break the cables as they are fragile?
 

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My backfiring/misfiring has REALLY subsided, still there but not bad. Things I did, running 93 octane gas, Added sea foam gas treatment, cleaned both mass air flow sensors, 2 weeks later I added HEET gas treatment. I think it was bad gas. Just my thought. IDchef56 did you change your thermostat?

Bob
 

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Discussion Starter · #9 ·
sorry for the late reply, didn’t have the time this week..

not sure thermostat is a probable cause for backfire and misfire.. mine is stuck open so the fan kicks on as soon as i start the car even when cold, so the car have trouble reaching operating temperature etc.. how many miles your car have? around 100.000km is a good time to change! in my case only 27,000km but this is a 12 years car and it was never changed.. im changing the timing chain next as delayed timing may be causing that (n14 engine on my car and no idea if it was ever done)

also clutch feels strange, may explain power loss in my car. again i think my case is particular since the car was driven less than 1500mls/year and i have no history

i’d try connecting your car to a good obd reader and check all values for something strange (fuel pressure, temperature
 

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I have 43k on mine. I can also MAKE it misfire. Other then that is runs great. My mechanic wants to look at it when the engine is cold so he can do the camera in the cylinders thing. I know he's not available for a couple weeks. I will update when I have news.
 
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