Hello everyone! This is my first real post on NAM, and after trying to revive some dead threads, I've decided to make my own. Please bear with me if this has been covered, I'm new to this forum and my search skills aren't great. Before I start, please note the car is a 2006 Cooper S R53 Manual trans with about 86k miles. Engine mods are 15% pulley, Helix CAI, and Cat-Back.

The Problem: Basically, about two months ago I installed a Marshall boost gauge using a tap off the horn of the supercharger before the intercooler. About four days later, I was on the highway trying to pass someone in 6th gear. When I put my foot down, I got a pulsing hesitation, and since then nothing I do has gotten rid of it. The hesitation only happens under 3k rpms, but after that the car seems normal, albeit slow. Shortly after that I got my first "check gas cap" light, and a day or two later a code for "high barometric pressure in the manifold." After some research, I ordered a new gas cap (the gasket on mine was bad) and a TMAP sensor. Neither of these things helped. So then, I decided to change the supercharger oil, and to inspect every inch of vacuum line while I had the car apart. I did find some lines that needed replacing, and also changed the MAP sensor as well. Again, still had the problem. After yesterday, I finally realized that whenever I get the code for the gas cap (which also sometimes triggers a CEL for "fuel system vapor leak") the car is exposed to water. The first time i got the "fuel cap" light, I had just washed my car using a self service bay at a local car wash, and every other time it has been raining outside. However, if it is just wet on the roads, I only get the "gas cap" light, but if it is actually raining I also get the "fuel system vapor leak" CEL. On top of this, every now and then it would stall if i hit the accelerator right after a cold start for a few seconds. This went from being once or twice to every cold start now.

If anyone has any possible ideas, please let me know. I really don't like going to shops, but at this point I think a smoke test at my local Euro mechanic is probably in my future. However, I will do all I can to avoid this without just throwing money at it until it goes away. The car is also much slower now, which only makes me more upset. Thank you to everyone for your help!! I just want Mini Mouse to be normal again!

 

can you show where you installed the tap for the boost gauge? since you have done lots if work since then....it really muddies the water....
what codes are you getting now?

 

The 'gas cap' warning should not be limited to just the gas cap. The fuel system is a high pressure system and if there's a leak anywhere it will show as poor performance all the way from the pump to the intake.


Also, next time you pull around to pass try downshifting a couple of slots to get into a higher torque curve. That puppy will do 70 in 3rd gear no sweat.

 

The only codes thrown now are the "check fuel cap" light, and the "fuel system leak" CEL. Both only throw when it rains. I have disconnected the boost gauge with no difference made. Today i pulled the cover off where the fuel filter is located, and I heard a inconsistent hissing noise with the car running. I learned the previous owner did the filter, and I'm now wondering if the noise I'm hearing is fuel going into the filter housing, or in fact an actual pressure leak from the gasket around the housing. Should I hear any noise from the housing at all? Thanks for the quick replies!

I do not typically downshift on the highway because this car as it was pulled well enough in 6th that changing gear was only needed in a quick maneuver.

 

You just might have located the culprit at the filter.


You also might have a lot of fun if the Phil Wicks driving academy comes thru your area sometime. They specialize in MINI driving. What you can learn on the track will go a long ways in raising the comfort level dealing with local traffic. Track driving doesn't just mean 'fast'.

 

I would love to get her on the track when she's all normal again. By far one of the best driver's cars ever made. Although the nice PA backroads have been keeping me content for now

 

We spent a few days in G-burg last year then meandered up into NY then over East a bit then back across Northern PA heading West on our way home. Fan-dang-tastic roads and beautiful countryside.

 

There is a vacuum valve at the engine on right side near the motor mount. Undo the hoses coat the nipple with Vaseline or dielectic grease and reinstall. If that doesn't do it there is an awful air pump diagnostic thing in the rear near the gas tank on right wheel well. It leaks internally and causes the CEL. Have fun with that one.

 

... Three MINI clubs are going up to Watkins Glen on the 18th for Opening Day, it be great if you get this sorted out and can join us. Check it out at: http://www.meetup.com/CarlisleMINI/events/220891437/

Now for your issue... There is another thing you can try to check to see if you have an air leak in your fuel system/ventilation system.. take an air hose with a air nozzle wrapped in rags to seal off the tank and inject air into the tank and listen for leaks, you may need an assistance to search as you hold the seal and air flow..and to swap with you so you can listen to any suspected leaks they hear.

There are a couple vent pipes (Items# 2, 9 ) and a charcoal canister back there... (see image)

Best of luck sorting it out...

Motor on!

 

Thank you so much everyone. I will try the air hose thing to see if I can find anything. I read a thread about that canister thing in the rear wheel well and some people have pulled it apart and greased the gaskets, however I will probably just get a new one for fear of it coming back in the near future. I might not have any garage time until this weekend (grrr) but I will update as soon as I get in there! Thanks again!