Hi everyone. I am the new owner of a 2003 Mini Cooper S that I purchased from my father. There are a couple of issues I am trying to track down that I am hoping I can get some help with.

Specifics
- 2003 Mini Cooper S
- 65k miles
- Rebuilt "Race" engine with oversized cams, pistons, 550 fuel injectors
- No Exhaust mods
- Pulleys- A 5 on the crank and 14 on the suoercharger
- Intercooler
- Catalytic converter...just a note here that I am receiving the 0420 error. From what I have read, this means the catalytic convertor may be going bad.
- New A/C compressor. The dealership thought the old one was causing a draw on the engine and it was binding. They replaced it with a new one and while it helped some, it did not solve the issue. See issue 1.
- New ignition coil and wires

Issue 1:
The damn thing won't idle...sometimes. This one is real hit or miss. But when I pull to a light and try and let the car idle, it dies. The boost gauge, when it does idle, rest right around -10 on the vacuum side. When it dies, it drops to -15 or -20. I can start it back up and keep pressure on the gas pedal and keep it going but it won't idle and then it will. So, it is hit or miss.

Issue 2:
Supercharger stall out when under heavy load.
I can reproduce this one consistently. When I really put my foot in it the boost gauge jumps up to 15 on the boost, then it absolutely craps out. It will jump down to 10, back to 15 then craps all the way down to zero. If I let my foot off, it will reset and I can jump back in it but when it hits 15 it craps again. The supercharger is a rebuilt one that was put on 300 to 5000 miles ago. It is making a bit of a rattling noise and the dealership said it is something I will need to replace in the future but it is ok for the near term.

Issue 3 - may not be an issue
A bit of oil in the intercooler. When I pulled the intercooler there is a little oil there. Mostly residue. Not sure if this is normal or not.

So, with all that said. I am looking forward to getting to know this little beast and thanks for any insight you can provide.

 

Oil residue in limited amounts are normal in the intercooler....the pcv gasses condense...and form liquid.
Not sure what a "stalling sc is"...frankly it sounds like you are over your head....making up explanations is usually a sign of this...
My guess is it is running too rich and needs a tune...would account for a dying catalytic converter....

 

No doubt I am over my head. While I am mechanically inclined, I have never had a supercharger and have a bit of a learning curve

 

Supercharger looses boost, and it doesn't idle sometimes, sounds like a vacuum leak somewhere.

The belt could just be slipping too.. You say it's also rattling so it could be the tensioner pulley and not the sc.

If you just had the sc rebuilt and it's making noise what do they say about it?

Is the dealer doing all the maintenance on this car?

 

Unfortunately, my dad had several people work on the car and didn't keep great records so I am piecing it all together. The supercharger was a rebuilt but was put on 5 or 6 years ago. My dad didn't drive it much after the repair. I spoke with Jan at Revolution Mini's, who did the engine upgrade, and he also mentioned a vacuum issue. Maybe that is where I need to start. I will also look at the belt for slippage. I didn't think of that.

 

The belt is the most likly culprit...
Check for which pulley you have...crank damper too...
Look for any reduction amounts (would be oversized for the crank), as this will change the belt used...
A 17% typically works well with a 532length belt, but a 535 works fine too...but in my experience the 532 means the damper doesn't Do much...so becomes a non-issue.
We see all types of folks here....some live in their own little world...so pointing out you are over you if head, and finding you have talked to JAN/RMW is a good start...knowing you need to learn is a first step.

 

Thank you. I have a ton to learn. I'm pretty good with my 88 VW Vanagon but this is a whole new beast lol

 

One thought...who put the SC on?
The sc gasket can be a bit of a pain...and us a one-time use item (sometimes called a green or orange gasket)...if it was done at home, it could be leaking...causing the vac/boost leak.

 

Just like VW, be careful with parts...but many parts can be had for a fraction of the OEM...the tensioner is about $100 on Amazon...just has the OEM name ground off...
On tdi forums? Or was your VW a gasser?

 

The VW Van is a gasser but I also have a TDI Touareg that is diesel. Not on the forum but I may need to be

 

A bit more info. My dad tells me that the pulleys were swapped. A 5 on the crank and a 14 on the supercharger. I put a screwdriver on the belt and it flexed fairly easily. I also used the screwdriver as a listening device and it sounds like the noise is coming from the bracket that the tensioner pully rest on. This leads me to believe that the belt and/or pully may very well be the issue.

 

How many holes do you see in the pullley tensioner tab? That would indicate the state of belt wear, or having a belt that wasn't small enough to begin with.

I'm wondering why the primary suspect wouldn't be the bypass valve. See:


Detroit Tuned says you need their stiffer aftermarket bypass valve to avoid the yo-yo power flutter form the bypass opening, but the above ModMini video says it's more a matter of just not having a broken one. Both quick and easy, and more involved, tests of the valve are in the video above.

 

Thank you for the reply.

I checked my tensioner pulley and I have NO holes showing. Does that seem right? When I place the tensioner tool on the tensioner, I can pull it back to reveal the two holes to put a pin in. Can you confirm?

Regarding the bypass. I dug into the car today and pressed the lever on the side of the bypass. It seems sound but I don't have anything to compare it with so I am not sure. There does seem to be tension and unlike the video, I would suspect no busted spring.

 

well the stalling could be the engine idle isn't high enough, which means theres no proper tune for the cam that you have.


for your belt tension, you want a hole showing, nothing showing mean that the belt it not small enough, the tensioner is almost maxed out.


oil in the intercooler is normal, the pcv system puts the oil in at near the front of the intake system.... which means it goes in the intercooler!


you could have had a tune, but the dealership could have reflashed the stock tune in the car. the 550cc injectors cannot be scaled by the stock ECU and require a tune. youll also run stupid rich on accel and have a hard time idling. stock injectors are 320 or 330cc
your cat could be gutted or ruined, hard to tell

 

Thank you. I am now trying to determine what pulley's my dad had installed. Looks like an ATI on the crank and an Alta on the Supercharger. Time to send some emails

 

Sounds like WAY TOO MUCH SLACK IN THE BELT...
Should have very little compression possible on the tensioner...
Not sure what size belt to tell you to use...
Neither of the sizes you mention for pullies are really common, even available?
USUALLY the crank damper is a 0-2+%
SC is a 15, 16, or 17%
A +4 was sold if I recall on the crank...but the alternator is ally needed a bigger pulley to prevent voltage issues there.... similar for the AC compressor....
A general rule of thumb...if you are the oversized. Crank to the reduced sc, the max should be about 17.....running closer to 19 is possible, but needs a custom tune and injectors....might be possible, but since a "race motor" is usually made to run at high rpms and a car setup beyong ax17% would do best at cruising withower rpms (water pump is getting overspun, since it's run off the sc, and a few other issues)....makes me wonder...
You can ZIPTIE the bypass valve open or shut to test it ..
Open...car will have less power than a r50...closed will always begin boost..

The valve does wear...2005+ cars had a stiffer spring from the factory that was "about right"but it also has a vacuum line and a spring internally...both can fail..leading to unusualness in operation.

 

The alta should have a % stamped on it....they tend to be 15%
The ati should be a 0% or a +2% unless another 3rd party was selling a larger one...
I would suggest that you swap the belt out as a first step...
At about $20 and 15-20 minutes, it's darn simple....even if you buy 3 belts to test fit them.
A 535, and maybe a 539 belt would likely be a good start if you cannot read the number on the current belt.

 

Can we back up again and have the chronology?

Was it running well before the cam, pulleys and 550cc injectors were installed? Was this car running well with all these parts installed? How long was it running with the new parts? Was it left sitting for a while? Or had something else done to it? When did it stop running well?

Also did the head and piston work raise the compression, requiring race gas? Above the common 91-92 octane premium you typically find? And if so was it driven much with normal premium?

It sounds plausible that it was tuned for the parts, the belt started to wear out, the dealership replaced the AC pump and reflashed the ecu while they were at it, and now here we are. Is that what happened?

Besides a correct sized belt, a quick and easy stopgap might be to put in some stock injectors, either the old ones or someone eles's take-offs, until a proper tune can be done to account for the cam, pistons and 550cc injectors.

 

UPDATE:

First, thank you guys, assuming it is guys as no one has put a kiss face emoticon on their post, for all you input and help. It has been great getting much needed feedback and education.

Second, I changed the belt. As it turns out my dad had one in the back of the mini that he had meant to get put on. IT is a K060530 and is 1379 mm in length. I can now see just over 1 hole on the tensioner tab. While this is nice it didn't fix the problem.

With the above said, I spoke with my dad and asked him if the dealership had flashed the car. He said yes but they told him that they only flashed their portion and the stuff Jan at Revolution Mini had done should still be intact. This sounded fishy to me so I called Jan and he said that is not likely. So I am ordering a flash tool form him and should know for sure by the end of the week what has been done on that front. I also ordered a vacuum leak tester from turboboostleaktesters.com so I can see if there are any vacuum leaks.

The two above test should at least get me closer to the issues at hand.

Dennis: to answer your questions, I am not sure nor is my father. The pulley's were put on ten years ago and the engine was done 5 or 6. HE doesn't remember the timeline of when things started to go awry. When I obtained the car from my dad, it had the stock injectors in it but I was instructed by Jan to put the 550's back in as the car would run poorly without them. So that swap was performed this week. It is definitely running rich now as I can smell it after driving.

Zippy: Unfortunately, neither the ATI nor the Alta pulley's have any sized nor product codes not them I can see. I spoke with them both and they said that without pulling the pulley's off and looking at the back of them, I won't be able to tell. What is odd is that in the case of the ATI crank pulley, the size that is on there, 5.375, is not one that is recommended for the Mini nor one they even carry. It was done so long ago they don't have a record and can't tell what was put on. You are correct when you say it is an easy swap though. While I had to enlist the help of my son-in-law, I was able to change the belt in about 30 minutes.

So, with luck I'll have some more information later in the week and be able to track down what is causing the trouble. I am hoping that all works out and they I just need to worry about it passing inspection in Texas.

Thanks again folks.

 

Can someone confirm that the stock crank pulley is 5.51 inches? If so, then I have a reduction pulley on mine that comes in at 5.35 inches. ~3% reduction.

Thank you!