MINI Cooper Forum banner

Acceleration Chirp

3K views 2 replies 2 participants last post by  Richard of the Hills 
#1 ·
Hey Guys....so. Randomly when I accelerate at higher gears, primarily 2nd to 3rd, 3rd to 4th, and 4th to 5th....i hear a series of "chirps" on the right side of my vehicle, more prominent with the windows rolled down. This does not happen every time I accelerate and seems to only happen when I need a burst of immediate acceleration, it's a quick few chirps that do not hinder my ability to accelerate, but are noticeable if you are listening for them.

ideas?

Thanks! -jazz
 
#3 ·
More Context/BG info re: my R56 2009 JCW

Okay...so in December 2017 my car only had 68k miles and was determined to have *complete engine teardown failure* as a result of oil getting into the engine and creating a sludge that was causing smoke to come out of my tailpipes (initially discovered during a smog certification check I had to get for vehicle registration purposes). Luckily, I had an extended warranty when I purchased the car in 2013 that covered powertrain and bumper to bumper up to 92k miles or 5 years. So this engine failure also caused the turbo to need replacement, along with a recommended new clutch assembly given it was at about 15% at the time. All said and done the repairs totaled more than $15k and the car, at the time, was only worth $11k...so my warranty was paid out and I was able to talk the dealer down to $1,200 for the repairs.

Prior to this, I had six months prior a need to replace the head gaskets and a leaky oil reservoir, in addition to a second timing chain replacement along with a recalled fuel pump. Again, my warranty came to the rescue.

Just a side note: I do not drive my JCW like a maniac and in fact I baby the heck out of my car and only push it when necessary, yet it has been quite the problem child journey, to-date.

As a result of the last YUGE set of repairs (took 3 weeks!!!) I now have the aforementioned acceleration *chirp* or could also be a loose part that only reacts at higher gear shifting speeds (odd), and I also have a rattle in front of my steering wheel on the dash when my car is engaging the clutch and going into first gear.

I'm hoping to bring these two issues up to the dealer with some clarity and help from you guys...I have a folder that is nearly 1/2" THICK of repair history...I'm starting to think they feel bad for me, lol.

But alas, I do love driving my car....when it is now broken :)

-jazz
 
#3 ·
Hi hi_jazz
The way you have described it, the "Chirp" noise when changing gears could be the diverter valve, which is perfectly normal. When at half to full throttle and you suddenly lift off the throttle to change gear, the turbo is still spinning and generating pressure. This pressure has nowhere to go as the throttle is closed (unless you keep your foot planted when changing gears, a VERY bad habit) and so the diverter valve (or blow-off valve) opens and lets this excess pressure escape back into the air intake, which makes a chirping or choofing sound. Without this diverter valve, the sudden excess pressure stalls the turbocharger, effectively braking it so that it slows right down. When you hit the accelerator again, it takes a second or two for the turbo to spin back up again- this is called turbo lag. This is exaggerated on bigger turbochargers- more spinning mass takes longer to slow down (so keeps producing pressure) but then takes longer to spin back up.
If you bought the car used, a previous owner may have fitted a vent-to-atmosphere diverter valve, which would give a very distinct (and loud) choof with each gear change when accelerating hard.

That's my thought.
Richard
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top