EDIT: Hey I probably don't have this difficult pipe. The picture shows that it is connected to the air pipe that goes from the throttle body to the MAF sensor. I've been running non-stock air intake since the warranty went out (2014). Don't remember having to disconnect a separate pipe down there. Been through two K&N Typhoon kits and both came with a smooth rubber elbow from throttle body.

Thank you! It seems to be next to the @#$& fuel tank vent valve. It is really tight back there and out of view from the top. 😭

 

So the PCV valve "lid with diaphragm" that I removed was slightly dirty but intact. I broke two lower clips off the new one while trying to get it seated right. In the end I used the old lid (with two broken clips too) with new diaphragm since it used to fit right. The valve itself is embedded in the valve cover with no opening that I can peek into.

The lid doesn't look like something that could impact the engine performance much, but the reviews suggest that it solves the problem for some lucky folks.

 

Started the car with the new membrane and can't say I felt a lot better. Is the PCV membrane/spring designed to lift and allow extra air/pressure to exist when there's too much? It is at the top of the cover and above the hose to the intake. It doesn't seem to take away from whatever is going into the main PVC hose.

Also tried to read from the obdii with a generic app for fuel info, still with limited sensors available. Will take her out around the block tomorrow to see if the membrane made any difference at all.

 

S Minis have a high pressure fuel pump (HPFP) and a sensor that reports fuel pressure to a scan tool.
Non-S Minis don't have a HPFP, and I believe they lack a sensor for reporting fuel pressure to a scan tool.
If you think that low fuel pressure may be causing the engine misfires, you can either check the fuel pressure at the fuel rail with a gauge or first try replacing the fuel filter.
With regard to the engine misfiring, I would be more inclined to chase out the cause of the cylinder 2 misfiring (BMW fault codes 27BC & 277D in post #6).

 

IF your misfire is isolated to a single cylinder, it's a relatively straight forward issue.

First check compression. If you have low compression, then you have to decide whether it's worth investing in the vehicle at all. If compression is good (>130 psi, and even across all cylinders), then proceed to check for spark/fuel.

Spark can be eliminated by swapping coil pack. If it still misfires on the same cylinder, it's not a spark issue.

Next culprit is fuel supply. Fuel pressure issues generally don't manifest/present as single cylinder misfires; rather, they cause misfires randomly in all cylinders. For an isolated misfire, it's possible that you have a bad injector. This too can be swapped to isolate, but injectors aren't extremely expensive so I'd probably swap the culprit with a new one. Be advised that removing the fuel rail will require injector seals on all four injectors.

I thought you were dealing with a random misfire across all cylinders, which is either a fuel supply issue or vacuum/intake issue. Apparently that's not the case.

 

Thank you! The codes were cleared properly for the first time using BimmerLink last Saturday. Haven't driven it since and will try today. Will confirm if the battery and PCV valve made any difference. Already ordered a fuel filter and locking ring.

 

Thank you! Compression was last checked in 2023 when the plugs were replaced. The numbers were good, as I was told. Could things have gone downhill since then with infrequent driving and no major disasters? 😨

At her age/mileage and current condition, she is only good as a mechanic's special. 😂 This is probably the point where folks leave her at a shop or arrange for a donation pickup. Now that my newer daily driver started needing repair (2017 CX-3 with 155K miles), I realize that I need a reliable backup car.

 

I'm curious how the reading is that high. N16 motor is 11:1 compression ratio; 14.2 (atmospheric pressure) * 11 = 156.2. That dial is indicating 195 psi.

If you're not able to manage the compression test yourself, you can certainly check the spark/fuel delivery issues first. I have a compression tester and usually proceed with that first if I suspect the other items are 'good' - i.e., I know the service history and have been driving the car consistently with no issues.

 

Thank you! I can't find/feel that hose from the top. If it is not connected to the pipe between throttle body and MAF, it must be sitting much lower. I will check from underneath when the car is on a lift for the water pump job. 😅

 

🤣 She must be a super Base. Will have it checked again. These are really more advanced items that I didn't even try to understand before. 🤦

This last test was done by the last MINI/euro specialist mechanic I knew in April 2023.

#1

#2

#3

#4

 

FYI, that's not how compression ratio works. Compression ratio is a physical measurement of volume, not ratio of compression pressure. So, an engine with 11:1 compression ratio will have a single cylinder volume of 11 units with piston at bottom dead center, and cylinder volume of 1 unit at piston top dead center.

 

Great! Once you are able to drive the Mini around town, recheck for BMW fault codes to see if 27BC & 277D return.

 

It will take me a few more days to fully understand what you two mean, but a quick search confirmed that a reading above 130 is good and 120 is acceptable. 195 is too good to be accurate. 🤦

 

She wouldn't start, just a click when the button is pushed, no crank at all. Tried several time. The door unlocked with the key fob and some dash lights came on with the click, but that's all. Could the BT obdii device drain this much overnight? The voltage reading is low 11.5 control module and 12.3 battery. Can't keep steady connection with the device either, it kept getting disconnected.

The last thing I did yesterday was trying to read the sensors with apps while the engine was idling in the driveway. Didn't touch anything after that.

The new battery is now connected to the maintainer.

 

Make sure the battery connectors are clean and tight. Then measure battery voltage directly between the two connectors using a multimeter.

 

They connectors were clean and tight when I put the battery in on Monday. Will check again this evening. The maintainer was still charging after two hours, when done, it would blink green. The ring connectors for the SAE battery connector were on the terminal cables and routed through the cabin air filter port so I can connect the maintainer quickly from the hatchback the power source.

 

What's the output voltage from the battery maintainer? Is the battery now showing a higher voltage?
Is the coolant leak now fixed?

 

No, that is how it works. You're taking the volume of air and compressing it to be 11 times smaller. I'll confess to having an old person brain fart and not remembering atmospheric pressure is 14.7 psi, but still....this is 30 psi over what I'd expect to see.

See linked from compression ratio calculator.

https://ngcalculator.com/compression-ratio-calculator

 

And just so you don't think I grabbed the first thing I found that supports my argument....here's more:

https://www.reference.com/science-te...5aedc74e6b59d7

 

The maintainer is now in maintenance mode. She still won't start. Last time I had a no-start surprise was when I put the MAF on backwards (air flow --> ) I just checked and that's not the problem.

I booked a lift/tools/help for the water pump job next Monday and have to postpone it. I was there this afternoon working on my Mazda.

MINI's Registration is due in August so I am just going to pay the renewal fee and try to fix everything by the end of the month. Won't be able to pass smog (and get the sticker) with the misfires and coolant leak. Hopefully I can at least get her to start moving again, then I can get a special pass to drive to the mechanic's shop with an expired tag.

 

Thank you!! I don't remember the mechanic saying that his gauge was off or that the numbers were too high. I wasn't familiar enough with the range of numbers to know otherwise, until you pointed it out. Safe to say that result was not valid indication of the true condition?

 

The compression tester gauge is possibly out of calibration.

Ideally, cylinder compression numbers (PSI) should not differ by more than 10%.
My gauge readings of the 4 cylinders:
#1 200 PSI
#2 191 PSI
#3 215 PSI (highest)
#4 188 PSI (lowest)

Cylinder 4 is 14.4% lower than cylinder 3.
Cylinder 3 is 12.6% higher than cylinder 4.

These differences are not ideal, but obviously permit the engine to start and run. Whether the differences contribute to the engine misfiring is up for debate.