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Lightly modified (intake, exhaust, intercooler, etc) done in 2013 had been running perfect. 60,000 miles. Trouble all started about two years ago when our local stealership replaced the thermostat. Since then been having multiple cylinder misfires, CEL, going into limp mode. No other codes. Pull over, shut down for a few seconds, starts up and goes perfectly, until it randomly does it again. Dealership checked compression (normal), replaced JBE, LPFP. When that didn't work they gave us our money back and told us to leave, saying the car was "highly modified", and we were not allowed to return to the dealership. Nice. Took it to an amazing local shop Babbet Motor Werks in Scottsdale AZ. On inspection they discovered the dealership put in the MAF sensor backwards, and with a smoke test found all intake hoses leaked, clearly they got everything lined up and forgot to tighten everything down. Fixed these F ups still having the issue. We have begun systematic long term maintenance, in order (plugs, coils, fuel injectors, walnut blast carbon clean, HPFP, fuel filter in the tank). Still throwing random multiple cylinder misfires. This ALL started when the dealership replaced the thermostat. Whomever figures this out for us is in for a substantial reward - thanks in advance for your help!!!
They replaced my thermostat, and in combination with that, apparently there was an “adapter” for the plug that needed to be ordered. He told me mini made the change in thermostats and some need a plug adapter.
your symptoms are IDENTICAL to mine. I’ve done HPFP, thermostat, plugs, coils x 2 times, cleaned k&n filter, I will check the MAF sensor. This problem came out of no where while driving down the freeway!!
I take it this is a MINI Cooper S. Correct? Chapman BMW or North Scottsdale?
You need a lab scope to look at the secondary ignition wave from when it's misfiring. That will help you narrow down what type of misfire you have.
In my case (N12 engine), I had a loose valve seat.
MINI N12 engines don't like two things. Being overheated and valve jobs; and, it's HOT in AZ in the summer! Both can cause valve seat issues. In your case; you mentioned the thermostat was changed. The cooling system only holds 1 gal of coolant, so filling it correctly is critical. The manual states to use a vacuum filler tool, and it works very well; I have one. If they didn't fill the cooling system properly and test drove it, it possible they overheated the motor and now you have valve seat issues; I doubt this happened at a dealership, but maybey the shop idiot was working on your car. Even without being overheated or having recent valve work performed, you can still drop a valve seat.
To fix my misfire issue, I pulled the cylinder head, and had the machine shop replace the shallow factory valve seats with the deeper SBI valve seats; 3 valves were bent too. Problem solved.
Hopefully, your problem is cause by something they forgot to connect.
Thanks for the reply! North Scottsdale. In my case the compression test and the leak down test were right on spec for each cylinder, which makes me think with all 4 cylinders misfiring it’s something to do with fuel, air, or electrical problem affecting all cylinders. When it does go into limp mode, I can push in the clutch and coast, shut down the engine for 15-20 seconds, fire it up and it runs fine for hours. It just resets. Even shipped the ECU to England for bench testing saw no faults?!?!?
QUOTE=mkov608;4671672]I take it this is a MINI Cooper S. Correct? Chapman BMW or North Scottsdale?
You need a lab scope to look at the secondary ignition wave from when it's misfiring. That will help you narrow down what type of misfire you have.
In my case (N12 engine), I had a loose valve seat.
MINI N12 engines don't like two things. Being overheated and valve jobs; and, it's HOT in AZ in the summer! Both can cause valve seat issues. In your case; you mentioned the thermostat was changed. The cooling system only holds 1 gal of coolant, so filling it correctly is critical. The manual states to use a vacuum filler tool, and it works very well; I have one. If they didn't fill the cooling system properly and test drove it, it possible they overheated the motor and now you have valve seat issues; I doubt this happened at a dealership, but maybey the shop idiot was working on your car. Even without being overheated or having recent valve work performed, you can still drop a valve seat.
To fix my misfire issue, I pulled the cylinder head, and had the machine shop replace the shallow factory valve seats with the deeper SBI valve seats; 3 valves were bent too. Problem solved.
Hopefully, your problem is cause by something they forgot to connect.
I agree with you, and I think you're on the right track. Mechanical failures won't reset when you cycle the key. ;-)
What I learned from my BMW & Scanner Danner is that the more modern engines will shut down the fuel injector for any misfiring cylinder. The DME does that to prevent damage to the catalytic converter; raw fuel into the converter is not good for it. When you cycle the key. The injector for the misfiring cylinder operable again ... that is unless that cylinder experience more misfires.
I did see a technical service bulletin for the ignition coils. In some MINI a certain brand of ignition coils were installed at the factory, and they had issues dealing with the heat and would fail. The OEM coil is made by Eldor; you can get them at AutohauzAZ for $27 each.
12-17-2021, 12:41 PM
