Updated: I finally got my supercharge belt replace today, and I am happy to report the problem seems resolve. It has been almost been another 18K on my card and the problem never really seems go aways, does not really matter what I did to the car until I finally decide to change the belt.
I just pick up the car and driving back to work, the car seems pull a little bit harder and a little bit more response after the belt replace.
I am keeping my finger cross that is the solution for my problem.

 

Updated: it has been a week since I replaced the supercharge belt and the car still run fine - almost like new, pulling strong after 2000rpm - the sluggish problem now is gone. Happy motoring again.

 

Enough time for the placebo effect to have worn off (I've had a few fixes that I was sure fixed it turn out to be just my imagination).
Thanks!
I'll do this asap.

 

Could it had been that the belt was slipping and this caused the poor performance ?

Can you confirm the mileage that you had the belt changed.

Thanks.

MiniKar

 

the MPG is almost identical 26.7 (before and after it start to have the sluggish problem). It has been two weeks after the belt changed and it still get the same mpg 26.7.

 

Spring and fall, many mini's have temporary performance issues....they seem to be assocated with the yearly changeover in fuel from winter to sumer+ visversa (done for vapor pressure). After 2-3 tanks, the computers seem to adapt....and return to normal.
Since some non daily driver mini's take 2 months to use up a tank of gas...some folks have the issue for a long time....

 

That happens to a lot of people, but this particular thead deals with a longer term issue.

A select group of us have had this problem for a very very long time.
Every day for years in some cases - I myself have spent lots of $ going back more than a year...this is not your average bad fuel issue...or "dip at 3000 rpm that all mini's have"...it is an extremely annoying problem that gets worse as time goes by.

 

I bought some Prestone Belt Dressing and gave the belt a nice working over yesterday.

Today the problem is gone. I'll give it a week for the placebo effect to wear off and then report back.

I checked my maintenance log - I started replacing fuel filters, coil, spark-plug wires, plugs, doing Seafoam, BG44K, PCV valve etc etc...2 months after replacing my serpentine belt!

I used a Dunlop replacement belt, not an OEM one...and yes, looks like my troubles started shortly after...

 

it has been more than three weeks now after i replace the belt and it still running good- and it get better mgp now - 28.3 so far.

 

I think I am having this same problem. More details and hopefully a video to come, but how do you differentiate between an issue with the bypass valve (BPV) and the supercharger belt in terms of symptoms? Any technical explanation someone can provide would be greatly appreciated.

 

Yes I am having the same problems mentioned in this thread. My car is a 2002 and has 176xxx miles, so I'm sure some of the problems are from age on the engine internals. I just spent $420 to replace the oxygen sensor and I still notice my car hesitating from 1000rpm-3500rpm (along with a strange high pitched whistling noise coming from the engine). I will try to zip tie the BPV today and I plan on buying some BG 44K to see if that does anything. I dont really have the money to replace the supercharger belt so hopefully so hopefully that is not it.

 

So I am experiencing low-end sluggishness.

I don't know where the MAP sensor is to clean it, but here's what happened.

This weekend, on my 03 Mini S, I added a 15% pulley, TSW upper motor mount and BSH lower motor mount. I get significant NVH, which I expected from the new mounts, but I get some major sluggishness on takeoff and when cruising at low RPM. This JUST started happening after I made the changes.

I did replace the serpentine belt with the supercharger pulley install, so it's not that. My car is leaking oil on the passenger side, but I can't tell from where. The bypass valve IS a Detroit Tuned BPV that I just replaced last year.

I have 112,000 on the ODO. Don't have a clue what it could be. Another member suggested that I look at resetting the "adaptives" so I am looking into that.

I have also reset the ECU and reseated the plug wires. Happy to report still no corrosion on the original coil pack.

I'm clueless and open to suggestions. Cannot afford to take her to a dealership.

Some pics of the oil leak and new parts.....

 

Thanks Dave. I did what you said (at least checked) and took a look at the MAP and TMAP sensors. I had to pull out the old Bentley...

Here are some pix:

MAP Sensor - spotless and perfect. So if it's bad, it's bad and not something I can see visually.





TMAP sensor had a little bit of oil. I tried to clean it...



Oil residue in there mean anything?



Put the sensors back in and there is maybe a hint of improvement, of course that just could be in my head. If the oil leak is related, it might all just be a coincidence. I changed the oil about 1.2K miles ago and I was half a quart low...

PS Dave, although I am in PhillyMini, the two little boys I have keep me from attending any rallies! I hope to get to at least a few this year but not looking good! So I don't think we've met.

That said I appreciate the offer. I may need to take my car into someone. Hate to do it, but the coincidence of me messing with stuff and having these issues is bothering me.

 

OK so a quick update this morning after I took the car on its normal 25 mile commute this morning. The NVH I am experiencing is (at least in my opinion) NOT from the new motor mounts.

It almost feels like something - maybe a pulley, a camshaft or something that is rotating inside the engine is loose or out of balance and THAT is what's causing the vibration. Once the car warms up there is barely ANY NVH while sitting. It is only when the car is cold.

Next, putting my foot on the clutch COMPLETELY eliminates the NVH while the car is moving at low RPMs.

Finally, when coasting with foot off the clutch from the 3,000 RPM range down to 1,500-2,500 RPM range you can feel the vibration pick up massively and then quiet down right before I put my foot on the clutch. It is almost like something is spinning out of balance or something. I just cannot put my finger on it. But putting my foot on the clutch does alleviate the symptom completely.

 

A lot must be waiting for clear defined fix to the symptoms in this old thread. Some say BPV, tune, plugs, wires, belt, fuel filter, MAP & TMAP, ethanol gas blend, electronic pedal, etc. Has anyone clearly fixed this codeless quirk?
We all know it's acquired & seems to be fuel supply related as it seems to run lean @ pre 3krpm.
Calling out all MINI gurus to chime in & help. What exactly is causing this? Hope to put a fitting conclusion to this topic. Thanks!

 

From what I can see of those pics that MINI was leaking more oil than a 30 yr old Harley.


~ Main bearing seal
~ Oil filter housing and "O" rings for the cooler.
~ I would put $ on him having a crank seal leak and oil pan gasket leak as well.

What belt is he using ? Is it the original or smaller one ?


He didn't have the problem until changing the right top and lower engine mounts with much stiffer aftermarket ones.

The original soft and worn out upper and lower engine mounts he just replaced could have been compensating for another undiagnosed rotational problem due to lack of lubrication and oil pressure......

Now only coming to light since there is nothing to absorb those rotational vibrations.

 

As this thread shows, cars are a complex combination of parts, and different parts can fail, resulting similat problems.......problematic yes. But that is why a good mechanic is a true artist. Cars are not like a computer where issue a=solution b.
simply trying to fix a car without basic knowledge or troubleshooting from any internet thread is a rescipie for a $$ time.
simply put, if doing y fixed problem z for a person, it may/maynot apply to person b. It may be someting to look into, but no 2 cars have the same history, and modding a car can change everything!!
Sorry to go off on a rant, but sometimes folks look at car repairs in an overly simplistic way....kinda like home renovations....and anybody knows when you tear into a wall in an old hose, you NEVER know when you will stop....that it why some contractors ONLY do new vs renovations......impredicibility.

 

Totally agree w/ your "rant", Zip.
Just been reading too much about this issue w/ no definite solution. Too many suspects for a single symptom.

 

While I agree with you on your rant, what is a mini owner to do when you have been to the dealer twice, and 2 other independent mechanics... That is what happened to me. I was annoyed for about 2 years with this, did lots of the things on this forum. For me, in the end it was the tensioner or belt. My dampener was blown, so I changed the assembly (I wish someone made just the dampener) and the belt. Ahh, much better (I believe the belt slipping a little bit upsets the system).
A few months later, I changed the exhaust (due to a leak) and wow, the car runs better than ever. I believe that the internals of the stock exhaust can rust and get loose, blocking flow and having something to do with this. I wish I would have sawn my exhaust open to look into this more, but there was definitely a real problem there. Also, I am not sure how to diagnose this problem (please don't change your exhaust just to fix this problem without a good reason), it is just another thing to keep in mind. I don't believe that the remus exhaust that I put on could be that magical- there must have been something internally wrong with the stock one.

 

I have an R53 with a 17% pulley and the one-ball mod. I have a similar issue with low torque from 2700-3000 RPM. The car has 98k miles. I will be looking into this issue and start with an engine computer scan. I may also try new plugs and a supercharger belt replacement. I guess the best we can do is all report on what fixes the problem for us and take it from there, because it could be anything.

 

R53's aren't any different than any other cars out there.......you need to keep them in good running condition if you want the best power out of the motors. Keep the SC belt in good shape, make sure the air filter is clean, if you have a bunch of miles on the plugs and wires...change them. Bypass valve....make sure it's working properly.

Also...keep in mind that these little motors aren't torque monsters under 3000rpms....they are pretty doggy. When you have a small displacement motor with a big heavy flywheel that also has to turn a supercharger.....at low rpms with not much boost they are going to be pretty weak. Installing a simple boost gauge is nice also...it lets you see how much boost you are making at what rpm......

 

Ian is spot on and correct about the boost gauge as a "health/trouble shooting" indicator for vac/boost issues.

I would also add to regular maintenance an intercooler cleaning, spray out all that shellac blow by buildup using a can of CRC non chlorinated brake cleaner ( the green can) and replacing the rubber couplers every 70K miles. They blow up like a balloon when engine under load, develop cracks and can rob the system of boost pressure.

 

I'd like to report that new plugs and wires made a huge difference for me. There's still a dip in that RPM range, but not as pronounced as before. No more low RPM stutters and big loss of power from 2700-3000. The wire connections had some rust on them, which makes me think that water can get in there when it rains from the inter cooler hood scoop.

 

It seems that all Mini S supercharger models have this 3,000 RPM dip. Check this out: https://www.northamericanmotoring.com/forums/general-mini-talk/114843-mach-v-mini-dyno-test.html

 

I have a very similar set up. 2003 r53, 16% pulley, one-ball mod, madness CAI. Makes you wonder if all the mods are the reason why. Tune could help but at the same time, mine has 109k on it. Haven't done a fuel filter yet, pulley belt is about 6 months old, haven't done 02 sensor(no codes yet) Haven't done a super charger service.... So who knows. I have the dip issue as well, 3rd gear doesn't pull hard till about 4k.

After reading this , it seems like it will cost me a ton of cash to find the issue