A couple weeks ago on my way to work I noticed a significant reduction in power when merging onto the highway. At first just thought I was imagining it, so I slowed down some then gunned it..... Sure enough the car is gutless.... And no sound of the turbo spoiling up. It still ran well enough, no missing, no CEL. Eventually the half power icon came up, but still no CEL. Stopped by my friends shop to see if any codes could be pulled, but it had none.

After some research I though it might be the HPFP and knowing that has an extended warranty I scheduled service in Albany (2.5 hours away).

Well it turned out that they say it's not the HPFP but rather the vacuum pump supposedly. The SW claims that the pump isn't producing enough vacuum and for whatever reason there is some oil in the vacuum lines. They want to replace the pump, and all the lines and possibly the vacuum box. Vacuum pump alone, they want $750 installed. They didn't have one in stock and couldn't get me back in for a week so I paid the $118 diagnosis fee and left. (FYI... Car is an 08 S with 71k)

So, being rather mechanically inclined on most cars I figured I'd just do the repair myself, but need help from the Mini brilliant to double check the diagnosis and explain to me some of principles on the vacuum system for this car.

Why don't I get a CEL with this problem?

If its truly a lack of vacuum, why do I notice no difference in the brake pedal as the booster is vacuum powered right?

I understand the wastegate is vacuum actuated so it makes sense that I have no boost if I have reduced vacuum, but other than that and the brake booster..... What other major systems are vacuum operated.

In order to test the pump do I simply remove the mainline off the top of the pump and attach the gauge there? How much vacuum should there be at idle?

Has anyone else had this problem? I know many have had a seized vacuum pumps leading to bigger problems, but what about similar issues to me?

 

OK..... more info..... the service writer had mentioned the vacuum lines had swelled and would just slide off of the fittings..... At first I didn't understand this because the vacuum line coming from the top of the pump (I sure for the brake booster) is clipped on..... but I just discovered the lower fitting from the pump and I see what the dealer was talking about..... the line is very loose on the fitting.... you can easily slip it off with zero effort...... there is some oil in this line.... but more of just a coating. With the car running I can feel pretty good vacuum pressure from this pump fitting. But without a gauge right now I can't measure it. The line is so loose I can imagine this is a significant source of vacuum leakage.... however I can not hear any leaking at idle.

So this answers one question.... why don't i feel a difference in the brake pressure.... well it's a completely different fitting on the pump.... leads me to believe if the pump is bad.... it still produces enough vacuum to operate the brake booster, but not enough to operate the wastegate...... OR..... the pump is fine and there is a leak elsewhere.....

What would be really helpful is a full schematic of the vacuum system.

 

Ok I now have a good understanding of the vacuum system for this car thanks to the linked schematic.

http://www.realoem.com/bmw/showparts...82&hg=11&fg=45

So now it's time to surely diagnose the problem part and where I desperately need input from the groups knowledge base.

I figured I would start by measuring vacuum out of the pump itself... From the nipple on the port what should the vacuum be and at what rpm should it be measured?

I found the following article that suggests the Boost control valve could be the problem.

http://www.etuners.gr/en/index.php?s=12&t=247

Now If the vacuum measures correctly out of the pump.... How do I measure vacuum out of the control valve..... Because I'm guessing the valve only passes on vacuum to the wastegate actuator when the computer tells it to ( under load).

Assuming someone gives me testing direction on that component and the part passes I will move onto the vacuum actuated wastegate.

Your help is appreciated!!!!!!!!

 

Update: the vacuum pump is suckin 25 in./hg at idle..... That's more than enough suck to operate the wastegate. Dealer diagnosis proved incorrect. The wastegate pulls shut when I apply only 15 in./hg using a hand pump and it holds with no bleed off.

So now I know the pump sucks just fine, and turbo actuator is just fine. That leaves the problem to be a vacuum line or the boost control valve that transfers vac to the turbo.

 

bill12s,

Apparently you are the first to have this problem and are in uncharted territory.
I'm interested to hear what you find out.

I just found your thread today, any update yet?

 

Bill12s

I think i'm having a very similar problem. However i can almost re-create my problem at will. Example: on the highway if im going, say, above 40 and i put it to the floor, it will spool up and take off, pulling very hard as expected - then *poof* it will just lose proably 80% of power, and no turbo, no BOV. the way i fix this problem is by shifting into sixth, and massaging the throttle, almost to 100% throttle slowly.. no turbo? let off throttle and start again... eventually after about 5 or 6 throttle pushes it spools up and takes off again. It usually wont happen below 60 mph, so hard off the lines are usually fine. however it almost always will happen if i trigger the "overboost" so usually my passes on the highway or spirited driving are throttle ALMOST to that button, but i avoid it to prevent the problem.

I bought my car used and suspect its chipped but have no way of confirming, has CAI and exhaust. 07 turbo automatic. Denver, CO. Altitude seems to have little effect, i recreated this problem (however not as easily) in Missouri this summer.

Let me know what you come up with. I'm very interested.

Also, not sure if this is related but i'll mention it for discussion - I seem to have inconsistent power on accel... very slight and hard to notice but just seems like im not holding a constant level of boost.. almost feels like a misfire, but i know it isn't ... doesn't feel quite the same. also, ill sometimes get a poof of rich fuel smoke out the exhaust, but this is in no correlation with the aforementioned problems.

Let me know man, we can email if you want.

 

Well one way to tell for sure if it's the control valve would be to hook a vacuum gauge to the line that runs from the control valve up to the turbo and see if it's passing on vacuum to the actuator when it should.

Can you replicate the problem on demand every time you want? I ask because, with vac gauge in place you won't have vac going to the turbo. When you punch it there will definately not be any boost...... Rather you will see on the gauge whether the control valve is attempting to send vacuum to the actuator. You'd need to drive slowly up to the speed you have the problem, then replicate the problem.... If the vacuum gauge suddenly jumps you know the control valve is trying to send vac to the turbo and thus its probably not the problem.

Also, hook a vacuum hand pump directly to the wastegate actuator and pump it closed..... Does the vacuum hold or does it leak off and allow the wastegate to open back up. It should hold closed.

 

where is this fitting?

 

Facing the engine from the front of the car...... Look slightly to the right of the turbo and you will see a vacuum actuator with a rubber line running to it. Pull off that rubber line and hook the vacuum pump there. Mine closes fully with around 12 to 15 hg/in. And holds perfect.

 

hello, I'm new to this site and in desperate need of help. when I'm on the freeway and i floor my 08 mini cooper S the check engine light comes on. from reading your posts I might either have a bad valve or a bad pump all together. I'm really confused because my breaks work great but when i pull off the vacuum line to the turbo's wastegate actuator i feel no vacuum, does it only work at high rpm's or should there be a vacuum at all times and more at boost? please help I've been dealing with this issue for a while and really getting sick of it.

 

You wont have any vac going to the turbo except under harder heavier acceleration when you need the turbo. Vacumn isn't directed to the actuator unless it's "turbo time".

I've since replaced my mini with a 2013 WRX..... but I still recall the exact fix for this problem. Despite all my typing and research above one thing was missed. Remember, when it comes to vehicle mechanics always start with the most simple cure. I skipped the most simple cure...... Turns out it was simply the vacumn lines themselves. I had replaced the above referenced Diverter valve and to my surprise..... It did not cure the problem. I then replaced the vacumn lines from the vacumn pump to the vac box, Diverter valve to turbo.... Basically the few lines that operate this system were all replaced with reg vac lines. Voila ..... That fixed everything. The lines looked fine, however a little swollen and no leaks could be detected prior to replacing them. Turns out one of the lines was collapsing under the vac pressure effectively stoping the entire system from operating.

 

Not sure if anyone has already said this but... You said you have am extended warranty? You shouldn't be paying for any of this or am I just crazy?

 

[QUOTE=bill12s;3708855]You wont have any vac going to the turbo except under harder heavier acceleration when you need the turbo. Vacuum isn't directed to the actuator unless it's "turbo time".

so i tried disconnecting the vacuum line from the pump to the air box? etc but not no vacuum from it, gave it lots of gas and still got no vacuum how can i check if its working properly. when i bought the car it had front end damage on it, so i replaced the turbo. after a while i noticed that the valve was not closing and adjusted it so it is. still get the same code and the valve does not move standing still!!!!!! can you get the valve to close or move without actually driving the car? i would have someone rev the car while i look at the valve on the turbo and nothing!!!

 

i checked the valve to make sure it holds pressure, and i think it closes the air flow not opens it? so there is not a overboost

 

I've been trying to work out a similar problem. Initially, this started with a mysterious oil leak that I assumed was symptomatic of the blown oil pan gasket. After replacing that and the valve cover gasket, a few weeks later, another oil puddle appeared. Upon close inspection, it turns out it was coming from the lines into the vacuum tank, which seemed simple enough to fix. I replaced the rubber fittings with vacuum hose, cleared the rigid lines and tank with compressed air @ 50-60 psi, cleaned it up, and put it back together. The first time I drove it, the "half-engine power" illumined, with the associated lack of boost, leading me to your analysis. I double-checked the lines and swapped the inlet/outlet positions on the vacuum tank (perhaps it has an internal check valve), with no effect. It'll be easiest to replace the lines and tank, but it appears something else is afoot...

There is a significant amount of oil coming from the vacuum pump nipple, and in the two short test drives I've had, that seems abnormal. There was quite a bit of oil in the vacuum tank at the onset of this repair as well, but I've had no CEL, or anything else prior to this. It's not leaking around the pump, but rather from the two vacuum fittings, particularly the one to the vacuum tank. I'm pretty thankful that if this problem is serious, it was caught before the vacuum pump destroyed my valvetrain, judging from other postings. However, before plunking down $300 to replace the lines, tank, and pump, I wanted to verify with others' MINI expertise.

1. Should there be oil coming from the vacuum pump at all, given this is a pneumatic system?
2. If so, how much oil is excessive? I know it's oil-fed, but anything beyond mist indicates blown internals to me, necessitating replacement.

 

My MCS-07 had a similar problem with boost handling.I changed the boost control valve and same time,for sure, tank air vent valve.Broken "vent valve" can leak boost pressure from manifold to tank and get no cel codes.Easy change same time,location under intake manifold.

 

For the past few months I have been having some power loss issues. In the summer, I would actually get the Limp Mode light and CC code, but no check engine light or stored OBD codes. When this occurred, it was usually on days when the ambient temp was 100+°F. Other than on very hot days, It has been so intermittent, that it was proving to be very difficult to diagnose. I am a retired ASE master tech, but rarely dealt with turbo cars when I worked in a shop. A few weeks ago, I noticed a coolant smell and discovered that Thermostat housing was leaking. During disassembly, the air intake pipe (Rubber Boot as Mini calls it) was torn at the clamp on the turbocharger and was soaked with oil. I thought that perhaps this may be the cause of loss of power issue and ordered both parts. After replacing the parts, the coolant smell/leak was gone, but I still get the intermittent power loss. In the past week, I have been smelling a burning oil odor, but only when the car is running. When I shut it off, the smell subsides within a few seconds. On further inspection I noticed a small amount of oil under the vacuum pump and decided to remove it for inspection. When I turned the shaft on the pump, oil spurted out at me which I thought was odd. I opened the pump to inspect inside and the chamber had quite a bit of oil inside. I conferred with another tech friend of mine and he confirmed my suspicion that this is not normal. I ordered a new pump and am hoping that both the burning oil smell and loss of power are cured. If anyone has any input, either supportive or contradictory, please let me know.

 

Just had this same problem recently on my '13 MCS. Was getting the limp mode and then started misfiring on cold mornings, eventually my brake pedal got real hard to press. Had no boost at all either. Family friend that is a mechanic pulled a vacuum hose and told me the pump was bad. We took it out and sure enough, it was broken apart on the inside. Told me to do oil changes more frequently, not the recommended interval.

Bought the pump from a local Mini shop for $200, was the wrong one, went back for a different, was still wrong. The guy got my car year wrong, so had to wait till next day. He could only get the part from the Mini dealer, ended paying $375, at his price. Bought ATF, spark plugs from him as well, super great prices too.

Installed the pump today, running like new again!