R56 - Cold Start Issue - HPFP or Carbon Buildup? Codes from scanner
 

Recently I've been having the cold start issue. I would start my car in the morning, then it would stall instantly. Would do 2 or 3 times before it started "normally". Today I had the same issue, but on the 3rd time my car shook like a carnival ride. I gave it some gas but no rev/RPM increase. So, I shut it off, started back up and it started normally. This time though, it threw the Check Engine Light (CEL). A co-worker has a OBDII scanner, so I scanned the codes and I had 11 it said (not sure if some are old or not though)

P0304
P0302
C0300
P0300
P0304
C0700
N/A
P0203
P0103

Any idea what this would be? I'm hoping it's High Pressure Fuel Pump since MINI should replace that under extended warranty.

HELP!

* MINI DTC P0103 (0x2778) - Mass or Volume Air Flow Circuit High Input
* MINI DTC P0203 (0x2D5A) - Injector Circuit Open: Cylinder 3
* MINI DTC P0300 (0x2781 or 0x2782 or 0x2783) - Cylinder Misfire, Several Cylinders
* MINI DTC P0301 (0x2771 or 0x2772 or 0x2773) - Cylinder 1 Misfire Detected
* MINI DTC P0302 (0x277D or 0x277E or 0x277F) - Cylinder 2 Misfire Detected
* MINI DTC P0304 (0x2779 or 0x277A or 0x277B) - Cylinder 4 Misfire Detected

My start would be to see if the injector fault holds and returns quickly; if so, that's your main lead to start with.
Otherwise, the faults provided aren't specific enough to rule in or out anything.

You'll need to systematically check the fuel system (specifically the pressure at the injectors) and check if there's an ignition problem.
Pull and inspect your spark plugs - those tell a lot on what's going on in the engine.

- Erik

Local shop tested the fuel pump, and the numbers it was reading are fine. They could not duplicate the 0203 fault.

Plugs are new and were fine. The tech also said the codes cleared themselves....like totally gone. Odd.

Issues started again. Same codes after sitting all day. Seems to run fine once it starts. Suggestions?

Bad injector is my guess. Causing all the misfires on other cylinders. But that's just a guess

If you want to do some diag cheap then just swap cyl 3 coil with 2 or 4 and see if the fault follows you can pull the plugs again and see if any one of them is WET. wet means fuel soaked

Swapping injectors is possible but more work. Coils /plugs much easier

Give it a try

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Strange that the ECU would not keep codes stored into memory, the only thing I could guess is it didn't occur long enough to be stored into memory. Last year when my MCS started knocking badly I never received any codes, the pre-ignition didn't last very long, under a second. The knocking didn't stop until after the walnut blasting, it stopped after 6 bottles of BG 44K.

That's why I swear by the stuff, it works by removing the carbon buildup do to oil vapors being burned! I always tell people don't stop at cleaning the intake valves because the combustion chambers look a lot like the valves did before the walnut media blasting.

My non diagnostic educated guess is.....HPFP but or course more diag needed. U checked fuel pressure from in tank pump? Need to do that.
My 09 did the same thing for months; no proper codes stored...not even misfire.
Dealer had it twice and were in denial. Only happens on "cold" starts i.e. first start of the day or night. Once it started properly it was fine for the day.
Did a WOT fuel rail pressure test and it was 85 instead or 120.
I finally made the call to change pump and issue disappeared
There is a bulletin and extended warranty on the pump.

If injector(s) were failing, you would see a short-to-ground or intermittent failure fault code specifically calling out the injection on specific cylinder.
The codes above don't dictate such; rarely do injectors fail these days too.

- Erik