Throttle position sensor (or whatever BMW calls it)? Could be loose or defective.

I know it's weird but the car does not start unless you pump the gas, trust me I have ran the battery dead many times trying to start it without doing so, maybe because it's letting more air in but it doesn't start unless you pump the gas.

Update, this weekend I removed the fuel rail and took each injector out and cleaned it. I took some brake line hose that fit tightly over the inlet of the injector, then fit the next size hose down inside of it, and kept doing that until I got down to the size of the straw that came with my carb cleaner spray. I put hear shrink between each hose transition to keep a tight seal so I wouldn't lose any pressure. Then I made a circuit with a 555 timer IC to pulse injector like the car would and activated it while spraying the carb cleaner into each injector one at a time. One of them did have a crappy spray pattern at first but it was nice an even when I got done. The others were fine. After I put the injectors back in I put some lucas fuel injector cleaner in the gas tank and filled it with 91 octane gas. It idled slightly better when I started it but still went from around 950rpm to 1150 or so back and forth. I took it for a long drive to let the higher octane fuel and the cleaner circulate through it. I noticed more power and smoother acceleration right away. The bucking when I let off the gas was gone. After 20 minutes of driving it ran not perfect, but passable. I could come to a stop and the idle barely varied, you really had to listen for it and you couldn't feel it in the car at all like before. I drove around town for a while and it was pretty good. After I took the car home and let it sit to cool. It wouldn't even start when I pumped the gas pedal. I ran the battery dead trying, finally I hooked the jumper cables from my truck to the car and worked with it some more. I finally got it to start by holding the gas pedal to the floor but the idle was back to bouncing again. Someone on another forum mentioned something about the thermostat housing, thermostat, or the coolant temp sensor and I know the coolant temp sensor was mentioned on here. If I'm not mistaken there are 2 coolant temp sensors, I unhook one and the hi temp fan won't work with it unplugged but it does function properly with it plugged in so it may be the other coolant temp sensor or that is a different kind of sensor near it, I will have to look at the service manual. I'm leaning towards trying that next since it runs pretty good when the engine is fully warmed up but I can't find the post. If anyone has any more thoughts with this new info I would appreciate it. I still need to check the throttle body as someone on here mentioned but it got dark before I got to mess with it anymore. Thanks for all of the replies. I really appreciate it.

Just like with a SU carb!

Pumping the accelerator pedal does nothing in a fuel injected vehicle but exercise your right leg. You got more issues than the ones you fixed. Follow the Good suggestions from the other posts.

I had a 2008 Clubman with 80-something K miles.

Consumed oil like a sailor on shore leave.

When we added oil, it would misfire badly.

Apparently, valve guides can come loose in the heads and slide up and down rather than just the valve stem sliding within the guide.

This link says that coil packs are a known issue. Perhaps that's what you've got going on??

https://www.mini2.com/threads/n12-n14-n18-common-issues.326570/

I don't have a definite solution based on your description, but:

a. Some other vacuum leak - try a smoke test?

b. Defective temp sensor in the thermostat housing? (may be setting incorrect air/fuel mix due to inaccurate temp readings?)

c. Vanos component failure...

d. Electrical connection failure with one or more of the sensors...

Sorry I don't have anything more definite, but these are my best guesstimates....

Hi,

 

I bought this car to fix up for my daughter. It has 76000 miles on it. When I got it you had to pump the gas like crazy to get it to start then it would idle really bad, rps would go up-down-up-down etc then it would die. The first thing I did is look at the spark plugs and they were very worn. I replaced them and then it would idle a little smoother but will still rev up/down/up/down etc. I did some reading and one person said to check the crankcase breather hose. It was broken completely in two so I thought hey, this will be a cheap fix. I ordered the hose, had to remove the intake manifold to change it so I replaced the intake manifold gaskets and cleaned the throttle body while I had it apart. It didn't have that annoying whistling sound from the crack in the hose anymore but it still idled the same. Next I removed both vanos solenoids and hooked 12volts to each of them, one clicked like it should, the other was more of a soft thunk. I cleaned both of them and put them back, no change. I bought 2 brand new ones and replaced them both, no difference. I tried my innova code scanner and it doesn't work with this car so I went to Oreillys and used theirs. The only codes were 2783-Misfirings several cylinders, 2773-Misfirings cyl 2, 2777-Misfirings Cyl 3, 277B-Misfirings cyl 4, 277F-Misfirings Cyl 2, 2782-Misfirings several cylinders, 2772-Misfirings Cyl 1, 277E- Misifirings Cyl 2, 2781-Misfirings several cylinders, and 2771 Misfirings cyl 1. I drove the car around and it has plenty of power, once in a while when I go to take off it would hesitate then take off really fast, also when I let off the gas at certain speeds it bucks really hard like a manual transmission car does when you slow down without pushing in the clutch (This one is automatic trans) I put some fresh gas in it and changed the oil with a good synthetic 5w30. In my desperation I starting unplugging different things one at a time so see what difference it made and I noticed it makes absolutely no difference if I unplug the mass airflow sensor, plug that goes down to the front o2 sensor, either vanos solenoid (allthough I did hook one up with it out of the car and I'm pretty sure I heard it click once) I tried unhooking the cam and crank sensors one at a time. whichever one is closest to the firewall will occasionally make the car die when I plug it back in. The one in front make no difference. I thought maybe the maf was bad even though I cleaned it so I bought a brand new one and it didn't help. The car is almost driveable if I turn on the AC to keep the idle up a little but I don't feel comfortable letting my daughter drive it this way. It does not have any death rattle from the timing chain tensioner at all. I took it to my mechanic because I thought maybe the timing could be off since these are notorious for that but he checked the compression and it was within spec and he said that should rule out head gasket or timing. I'm not so sure about that because I noticed some smoke coming from the tailpipe this morning when I started it. I had him hook his Snapon Soleus scanner to it and he said in live mode It was misfiring prettu much constantly on Cyl 1, periodically on cyl 2 and 3, he said he didn't see a misfire on 4 but there is a code for it so it must misfire at least once in a while. He did give me the following data from his scanner in case someone on here could make something of it:

VANOS Exhaust Spread Actual Value (cr) 120   Inlet Camshaft position (cr) 691   Exhaust camshaft positon (cr) 281    Adapt Valve inlet Camshaft (cr) 0   Adapt Valve exhaust camshaft (cr) 0 Eccentirc Shaft setpoint value 6526  Eccentric shaft actual value 179  Valvetronic relay - closed

 

 ANOS inlet spread Setpoint value (cr) 115  VANOS inlet spread actual value 116  VANOS exhaust spread setpoint value (cr) 115 VANOS exhaust spread actual value (Cr) 120  Inlet Camshaft position (cr) 102 Adapt Value inlet camshaft (cr) 0 Adapt value exhause camshaft (cr) 0

 

Today I checked the fuel pressure, it was around 52 and as soon as I shut off the car it would slowly drop once it got down to 40 I unhooked the gage so I don't know if it would've kept dropping. 

 

I also replaced that diaphram on top of the valve cover that is common to fail and it made no difference. 

 

I'm hoping with all of this information someone can point me in the right direction. I did check all of the fuses in both fuse boxes and there is voltage to the MAF sensor. 

 

People keep telling me to replace the timing belt kit just to see if it fixes it but I can't afford to spend $300 labor and the cost of the parts if it won't help. All of the other parts I have thrown at it were cheap.