So last week I started having problems with my R56. It wasn't delivering power, the engine shuddered when you start driving etc, but it was still drivable. I took it into the dealer (Alexander MINI) and they diagnosed that I had excessive carbon buildup and that my thermostat was bad. They wanted to charge me $1145 and $723. Cool. I looked up the thermostat fix and decided it was something I could try myself. I finished up a few minutes ago, and now my car won't stay. It turns over, idles for a few seconds, and then just dies. I was thinking maybe i plugged in one of the connectors in the wrong spot, but during the process, i noticed they had notches that only let you plug em in to one spot so I kind of ruled that out. I was wondering, now that the car detects that the thermostat is working, the carbon buildup issue became very major. I would pull the codes, but unfortunately I don't have a code reader and I don't have a ride to a parts store to get one atm.. I was wondering if anyone had run into this before and what the solution ended up being.

Thanks in advance for the help guys.

 

I just had my thermostat replaced on mine. The carbon buildup thing I keep hearing about on our cars and its new to me. Reminds me of 2 stroke dirt bikes when I did those. But Probably something simple for your solution and I want a code reader too because I refuse to pay BMW dealer shop fees if I can avoid it too

 

http://youtu.be/p3mIIO7K1KU
Here's a video of what's going on. Also sorry if a similar issue has been posted, I just couldnt find it through the search or on google.

 

Tomorrow you will be getting info from guys that know way more than me...

But this seems electrical and something resettable, like the CPU is "telling" the car to shut down

 

Thats what I'm hoping. I'm gonna pull the plugs on the harness and check em, maybe I did plug em in wrong.

 

I also noticed you have the "light bulb out warning" immediately when you try to start the car. I had those when I started doing the LED experiments with a friends Mini. Thats another story an im still learning the right way to do that. Hopefully something really easy for your fix. They're amazing cars, almost too smart... Haha

 

If i had to guess, you prob have a plug wrong. I did when i did my thermostat. Even tho the plugs have tabs, its easy to over power the tab and connect the plug. They should be color coded. Green plug to green socket, brown to brown.

 

I'm gonna go check my connections again right now.

Edit: just got done checking my connections. The brown connector doesn't fit onto the connector on the thermostat. And that brown one was actually connected to one of the o2 sensors that goes into the turbo inlet. The light blue one when into the engine block. They dummy proofed those connectors. The tab sizes are specific to where they go. I tried stuffing the brown one into the brown connector on the housing and it would not go in. I had read on another post where a gentleman did his thermostat swap and plugged in the wrong connectors, but his car just went into limp mode. Mine won't stay on.

 

Update: so car turns over but doesnt even fire anymore. Something tells me this is some sort of fuel/pump fueling issue...

 

Gonna have to dig back into it and make sure all connections done. Check the fuses first. Maybe u popped a fuse

 

i checked the connectors this morning, if you see my above update. I'm about to go check fuses right now.

 

Car started up. Didnt do anything except try to start it back up.

 

strange....Any CEL?

 

I have had/am having similar-ish issues on and off after a replaced temperature sensor followed by a replaced thermostat. I've found out a little about it here and there.

It seems like the car is misreading its engine temperature, and will not start to prevent damage it thinks it will cause. You might notice that it runs rough until it warms up or that it cranks a little more than usual, and that your MPG is down a little because it's running too rich.

Did you ever get an overheat alert on the tach while trying to start? I saw that once or twice - but again not reliably.

Do you have anything like a scangauge or accessport you can plug in and pull the coolant temperature or error codes? Mine currently has a code indicating an invalid signal from the coolant temperature sensor, and occasionally claims that the coolant (immediately following a cold start in -20 weather) is at 270+ degrees(!).

My current theory (since I've gone through effectively 3 sensors now) is corrosion on the plug increasing the resistance... or possibly a misplugged wire (although like you I'm not sure how that's even possible - they're colour coded, specific sizes, and don't seem to reach beyond their specific sockets). I'm just waiting on a free day to take a closer look on it.

Be warned - even if your car runs, it can at complete random decide it doesn't want to anymore. I had my car stall out while backing into a space at work and then pull the "crank but not turn over" thing. I had to push it back into the space. If this ever happens to you and you're in trouble, try and unplug the temperature sensor. Without a signal, the engine assumes default values. It'll throw a CEL, and may go into limp mode, and it'll run very rough, but it will at least start and get you out of an intersection / to a dealer.

 

Update:

The plugs were in the wrong way round - in my case the MAF and ECT sensors. This obviously doesn't help you - but I would still suspect it's ECT sensor related given your symptoms and the work you've done. Have you tried swapping the ECTS for the one from the old housing to see if you just have a faulty one? I'm sure I read somewhere that they actually had a fairly bad failure rate.

[For others who stumble onto this with similar issues: The three plugs on that harness are all more or less identical, and are coloured green, brown and grey. Two of the three sockets are colour coded grey and brown. Your assumption would be that they all match up by colour.

You would be wrong.

If you look at the plugs themselves they all have a tiny ridge on them that "keys" them to the right socket - in the case of the MAF and ECT, the ridge for one is between the pins, and on the other it's outside of them. However the ridge is tiny, and the sockets are flexible, meaning that you can fairly easily plug them in the wrong way without any resistance.

In my case the green plug went into the (brown) ECT sensor, and the brown plug went into the (black) MAF sensor. CEL cleared, car starts better, etc etc etc.]

 

yeah, mine were plugged right for the get go. I dont think i ran the heater long enough to get everything running so the motor just kept dying. As far as the "carbon buildup" issue; I got that looked at an independent shop and the tech said that wasnt the issue. He did a compression and leakdown test and everything checked out. He said it might be something minor like a warped intake or a blown hose somewhere as the engine misfires are random.

 

Are you experiecing same running/not running issues as you were when dealership diagnosed it as Carbon buildup or did these issues only manafest after your recent repairs ?

 

the thermostat issue(fan would run after my car was off and would kill the battery) started a few months back. The lack of power issue was what got me to take it to the dealer and get it checked. The thermostat replacement did what it's supposed to (stop running the fan because it thought the engine was too hot). The power issue is separate from the thermostat replacement.

 

Update: So I took it to a mechanic and he did full compression and leakdown tests and the motor is actually fine. As to random misfiring, he said the car is giving him a headache as everything seems to be in order. Could this potentially be some sort of ECU issue? The car is bone stock.