Thanks for the update.

So my most recent attempt was to replace the gas tank breather valve/solenoid. It was suggested that perhaps the hose on it that connect to the intake manifold could be cracked, or the solenoid itself might have failed. The car was really happy, but this wasn't a fix...

I created a little pressure tester to try charging the boost pipes going to the throttle body. I disconnected the turbo outlet and pressurized it then went into the car and turned on accessory mode to check my Ultra Gauge and read the pressure to see if it was constant. Unfortunately it wasn't reading constant (small constant fluctuations) and I was rushed to do it, so I didn't get a fair evaluation. But from what I did see, it seemed as though my intake manifold was reading a lot of pressure, (I pressurized it to about 15-20 PSI) and I'm wondering if my throttle body isn't closing enough, or something along those lines.

I need to figure out which sensor my Ultra gauge is reading the MAP from so I can assess what do do next. 
The hunt continues. When I have a few hours on Tuesday or Wednesday, I will check it again and report back. 

MortyMiniC137,

Any updates on your situation? Originally, I thought I had a similar problem and have been following your progress. My 2012 MCS has HPFP and Fuel Rail Pressure wiring issue that I've been dealing with.

Gotcha! This is something to look into for sure. I know I'll be going to a de-CATed DP and getting a tune in the next month or two, so this may help if that's the issue. The CAT could be caked up with sludge from the engine I assume? Half-burned oils and fuel, as well as anything from my carbon blast/seafoaming. 

A higher than normal backpressure would indicate a potential restriction in the catalytic converter from contamination. This can cause rough running engine and can potentially shorten the life of the turbo.

So is this just to check the back pressure? And if the back-pressure is higher than normal, would having a cat-less downpipe fix this issue? I already have a different 2.5" midpipe installed, so I should have slightly better flow without the secondary Cat. 

I swapped the upstream O2 sensor for a new one and it didn't change anything. 

Generally speaking, more than 1.25 psi of backpressure at idle, or more than 3 psi at 2,000 rpm tells you there's an exhaust restriction.

The exhaust pressure gauge can be used at the upstream O2 sensor port, just above the catalytic converter. Remove the O2 sensor, secure it away from any moving parts, then install the gauge. This will trigger a check engine light, but it should clear itself after the sensor is re-installed and driven a few miles.

That something I'm genuinely not sure about.

Would I hook-up a compression tester for pistons? Or do I need to run the car with some sort of gauge hooked up?

Im concerned measuring the back-pressure may be really hard because flowing exhaust gases should create some sort of positive pressure.


Side note: I replaced all the vacuum lines with some silicone ones and got a performance intercooler installed. Its the borg-wagner coated IC and so far I have hit 21PSI in sport mode. Thats the highest boost pressure I have hit yet, and it didn't throw any codes, CEL, or limp mode. 
It seems like cold starts and until the car is at ideal temps, it wants to do all of the above, but if I clear the codes after stopping and the car is at temp, I can usually drive without any problems, more so in sport mode.

Since you mentioned the O2 sensors, I started to wonder the condition of the catalytic converter? Any way for you to check the back pressure at the upper o2 sensor port? (this would also cause premature wear in the turbo.)

Thanks for the response, it's very helpful as always. 

I replaced the hose with a reinforced rubber one for flexibility. 

Yesterday my new MAF sensor came in and I swapped it on the car, but it made no difference.

I am thinking your valve-lift situation is very plausible, as well as an O2 sensor (top) problem. Something I read said that a faulty or problematic O2 sensor will cause rich conditions. Since I'm no longer seeing misfires consistently (like one or 2 pending, but never fault and never the same cylinder) I feel the valve high-lift issue is less likely. Therefor, I will try changing the O2 sensor first. 

Have you replaced the PCV hose - the one with the sheath covering it? - I have read the sheath hides cracks in the hose....

Here is something I found that might be related:

UPDATE:
Its very hard to tell what disconnecting the MAF did, the car kinda freaked out but then it kinda acted the same. I am going to let the car get to temp driving it for a bit, clear the codes and unplug the battery for a bit, then start the car with the sensor disconnected and drive it, to see what the engine/computer think.

I actually replaced the turbo 2 days ago and while I have more boost and more consistency, I am still getting P1497. I genuinely thought this would be the fix, I was relying pretty heavily on the idea that the waste gate was not sealing properly or operating properly. 

I'm going to upgrade the intercooler and hopefully my oem one is cracked. HOWEVER, I need to understand this code more.


People have stated its an amount of unmetered air after the MAF, but that's very broad. Does this mean positive unmetered air? Like somehow I am taking on more air pre- or post-boost? Or could this be as far as the CAT sensors, like I am seeing more air somewhere post-combustion or is one of those sensors defective? 

If anyone has any insight on this code, it would be greatly appreciated. I have spent over $3k and 95% of my own time and labor on this single problem. Today is a day I am actually discouraged about my outlook on this car. I want to restore and improve it, but if I can't keep spending every bit of my money and free time just fixing my only car.

How did it go?

This, and replacing the turbo or other sensors, are the last things I have to try. I'm going to try this this evening. Thanks for the input!

 Without commenting on all the things you have done and what the problem might be, whenever I have had a problem with any of my  fuel injected engines I have had all sorts of misleading codes, but the first thing I have done is disconnect the mass airflow sensor and let the engine run on default settings. Easy to do . If that solves your problem then just replace the MAF .I have no experience with a direct injection engine but surely it has a MAF. 

So I ended up replacing the VANOS solenoid because of something else I had read. It roughly stated the VANOS system can have adaptations and an intake valve can get stuck in a weird rhythm of high-lifts while the car might be operating at an economic pace with lower lift and fuel levels. Sometimes this came from a failed VANOS solenoid, and the design has been updated so I gave it a swap, and changed oil and filter. 

Last weekend I pulled the vent house that goes to the intake manifold and inspected it for cracks. There may have been a small hairline split, so I actually pulled both quick-connects off each end of the hose and slipped them into the ends of a 3/8" reinforced fuel-safe line. Now the line it a smoother curve in it with no bends and fits nicely. 

I took my hose to the intake manifold off when I pulled out the VANOS solenoid and found a small collection of what seemed to be road-clay and/or rust-dust. It the weirdest thing. I am assuming it could be from a failing turbo or the intercooler itself. 

I still have a check engine light and can trigger lim mode whenever I want. I still get P1497 constantly. I am going to change the turbo next week, butI am worried this may not be the whole problem. Any ideas? 

keep us updated...

I may try that. I changed the diverter valve and it fixed nada, I also swapped out the gasket on the pcv hose on the passenger side in case it was leaking at the connection. I am gonna be throwing a new turbo on it in a week or so, we will see if that fixes to too. But in the mean time I may order that hose with the turbo install parts. 

If the pcv outlet is leaking, would a new pcv hose fix the problem? Conditions are different at idle vs when loading the engine under power. I would eliminate this issue as a possible contributing factor....

So I did a walnut blast on the intake track, replaced the intake manifold gaskets, did the timing chain and guides, replaced the crank seal and my belt. Then I did a little seafoam treatment to clean off any dust and residual gunk. 

I smoke-tested the car again and the pcv outlet (that feeds back into the intake track) was leaking at its connection to the valve cover and a tiny bit on the intake side. I did my best to reseal these and replaced the hose so it would be less stretched out. 

The car idles wonderfully and start-up is pretty quiet. I went for a drive with the Mini mechanic that helped me out, and after we let the car get up to temp, we tried giving it some oomf. It still threw the P1497. I drove it yesterday to and from work and ran the codes, it also showed a misfire in cylinders 2 and 3, as well as a multiple misfires code. 

We smoke-tested the car 3 times and only found the pcv 'exhaust' side that feeds into the intake track, to be the only slight problem. We got it damn close to not leaking anything, and the mechanic assured me that it can't be that, the leak isn't big enough to allow any air in if were under vacuum. 

I have replaced almost all the failure-prone parts I am aware of, aside from the turbo and diverter valve. A Mini specialist suggested I do the DV because even if under inspection, they seem okay, they can often have failures you can't see.

I am considering doing the pressure converter, boost lines, and DV.

Any thoughts? I am bleeding money at this point, my car has a factory tune and does not see any harsh driving conditions. I am kind of disappointed because I haven't pushed the car in months and every part I replace make the car feel even better, but then the limp mode always returns.