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Brand new. It's been acting this way for a while, in the meantime I got a new battery because my old one died but it didn't change anything with this issue.
That's next on the list. I'll pull it off myself and check it. If it needs to be cleaned I'll do that as well and eliminate that issue from the equation. I'm not leaning that heavily towards carbon because it runs so good outside of this startup issue. No misfires, no codes, perfect idle. The only 2 issues I have observed are this startup issue and the exhaust smells a little rich all the time but that may just be like that by design.
On start up they smell a little rich due to the cat not being very hot at first, thanks and let me know what happens. Sometimes you will have stumble, no code or anything with the carbon build up gets to the point right before the CEL.
The strange part is that it runs terrible on startup and after about 15 seconds it's like a switch was flipped and it goes from barely running to perfectly smooth idle. Perhaps this is the computer adjusting itself?
I'm on my 2nd HPFP in 75k miles, not that it couldn't fail again. Last time it failed it had the same symptoms but showed low fuel pressure when scanned real-time, indicating pump failure. This time it has the symptoms but fuel pressure is right up where it should be the whole time it's sputtering and almost dying out.
Also, when driving in sport mode, upon hard acceleration it almost feels like it's starving for air or fuel. It's a weird feeling to explain but basically it's trying to go as fast as it should but can't. This leads me back to carbon. It's going in the shop Wednesday, hopefully I'll have some answers soon.
So my MCS misfired again this morning, all codes P0301 through P0304. I just performed a carbon cleaning and changed plugs 2 weeks ago which completely took care of the rough starts and misfires I experienced every morning. These misfires were much smoother and it took 4 start/stops before the car ran well again. I did not get any fuel codes and the fuel rail pressure at idle was around 675-700. Car has 66k miles and I am OCD about my oil level. It was 40 degrees and rainy this morning and I still have the old version of the intake manifold. Any ideas? Coil packs, HPFP, cold weather manifold? Thanks in advance.
If its warmer, should not be the the intake manifold. You are pretty far south. The coil packs are about the easiest thing to change, so you are getting a misfire on all four ? If so might be the HPFP since it takes a couple start stops.
If its warmer, should not be the the intake manifold. You are pretty far south. The coil packs are about the easiest thing to change, so you are getting a misfire on all four ? If so might be the HPFP since it takes a couple start stops.
Thx bud. I was thinking the same exact thing. This time around the misfires were real smooth and the car just shut off without the rpms bouncing around as much as they did when I had carbon buildup. Is it necessary to have a HPFP issue without fuel codes and accurate fuel line pressure?
Welcome, yea, in the beginning people might not get the codes. Or they were cleared once and are stored on the modules. Seem like the HPFP does not like to throw a code till its a complete fail.
Welcome, yea, in the beginning people might not get the codes. Or they were cleared once and are stored on the modules. Seem like the HPFP does not like to throw a code till its a complete fail.
Good to know. I checked the stored codes and had nothing. Appreciate the feedback. I'll give it a few more days and probably take it to the dealer for diagnosis as it has never been replaced.
I spoke to the mechanic, he said there were a lot of misfire codes stored, understandable for how terrible it runs for that 20 seconds every morning.
He really doesn't think it's carbon because of the way that it goes from coughing out and barely running to running perfectly as if someone flipped a switch.
He doesn't think it's the HPFP because there's no pressure loss or drop - it maintains proper pressure the entire time.
If we look towards an electronic issue, some sort of ignition breakdown, where does that lead? ECU? It runs flawlessly with full power outside of this startup issue.
Start - runs strong for about 10 seconds.
Starts sputtering, misfiring like crazy, almost dies out but never does for about 30 seconds.
Instantly goes from that to perfectly smooth idle after the 30 seconds.
This is a daily ritual. Now also does it at lunch and at the end of the day when I leave work. If it sits for more than about 4 hours it does this process.
Aside from throwing expensive parts at it, we're kind of at a loss.
Wanted to update this thread, it's been a while. Took the car to a different mechanic, finally got a little more insight. He found that the pipe going from the turbo to the intake was cracked at the base. He sealed the cracks with RTV and taped them as a temporary repair until I order a new pipe. I immediately got more power back and lost the surging that I mentioned earlier in this thread. I haven't had this power in so long I forgot what it was like.
He also found that the intake gaskets are leaking on the back of the engine where the manifold connects.
The initial starting problem still exists but he thinks it will go away when the intake gaskets are replaced. He said it runs so bad because of the vacuum leak - once the computer compensates for the leak it runs like normal. He said it's running rich as part of the compensation for the leak. He quoted me $1000 for parts and labor. This seems very high but I know it's mostly labor. I can change the turbo pipe in 15 minutes myself but I don't know how difficult it's going to be to remove the intake and replace the gaskets. Is this a big job? I still want to sell it but I have to fix it first.
Sorry to drag this thread out of the archives but we recently had the same issue on our 2010 cooper S. I had a look at our intake hose between the MAF sensor and the Turbo inlet and it had split open under the hose where you can't see it without removal. I guess this was causing a lean condition which the computer would eventually compensate for but initially it just couldn't so the car would misfire / sputter and sometimes stall. I got a replacement hose from Rock Auto in three days which is amazing during these Pandemic days. Once installed I cleared the misfire codes and she's running mint again. Quick easy fix which is very odd for Mini.
