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Ignition On ...
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Discussion Starter #1
Hello all,

Need your help for a problem that is starting to drive me mad.

My R53 has been having a little problem in the last few weeks, to keep it short:

The problem in general: when driving and starting to accelerate, the engine does not respond to the accelerator input and drops into limp mode. If i turn the engine off then on, limp mode is gone and i can drive normally, but it may drop into limp mode again later.

Some details:

1. generally when the engine is cold the problem is worse
2. the problem generally occurs at lower revs and when accelerating gently
3. on average, the problem may happen twice on a 30 minute drive from cold after which it generally doesn't happen.
4. my local garage found a throttle body error code
5. i switched out the throttle body with a second hand one.
6. the problem worsened about 30% and normal driving was less smooth
7. i entered the on board computer and reset the ECU
8. the problem returned to its previous state and normal driving was much improved (to better than before)
9. took it to the local garage again. same error code. they checked all the tubes and signal from the accelerator, but found nothing.

Now, at the same time, the car has another problem that i have tortured myself trying to prove and disprove a connection. Some months ago the fan / serpentine belt start to make a noise due to a split in the belt that was hitting something; very soon after part of the belt was stripped off (about 3 mm of one side of the entire belt). I had the belt replaced and all was well for a very short time, but i started to hear the little screech and broken rumble of a bearing. This worsened over a couple of weeks then i turned on the AC and the belt started to slip under acceleration, then one day smoke started to come out of the bonnet. On checking, i could see the smoke was from the belt and there were lots of small shavings in a few areas around the belt side of the engine. The bearing noise got worse, but is intermittent: sometimes it is rattly, other times a coarse grind but most times silent. The AC now no longer works and i don't think the AC clutch is engaging.

So, obviously i need to get the bearing (whichever it is) sorted, but could it be an excess tension in the belt from the bad bearing that is causing the limp mode too? Could the noise of the rattly bearing (which can be loud) cause some sensor to trigger like the TDC / knock sensors and drop into limp mode? Does it seem like the intermittent bearing noise is related to the AC?

thanks all, and sorry as i said i would make it short, but you kow the way it is with these problems when you start writing about them hahah!

ANyway, lots of thanks for reading and really hope you can offer some advice.

Thanks,

G.
 

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Ignition On ...
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9 Posts
Discussion Starter #2
Hi All, i am still no closer to understanding the issue, any guidance you could provide would be appreciated.
thanks.
 

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7,173 Posts
more likely to be the bottom pulley torsion damper ie the rubber pulley breaks up and slips this looses boost and causes all kinds of related codes and limp modes, below link
 

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Ignition On ...
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9 Posts
Discussion Starter #4
Thanks, Mike, this is an excellent lead. I searched on YT and found a video (not sure the link will be allowed, but
- MINI COOPER S R53 crankshaft pulley problem) and from 10 seconds on, the sound is the exactly same and also intermittent. the difference, however, is that in the video, when the noise stops, the belt does too. mine does not do that, could it still be the same issue?
 

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7,173 Posts
at first the belt still turns sort of but the pulley slips and starts and stops,, pull drivers wheel off and inner plastics and have a look when its running put a white mark on the middle of pulley and white mark next to across the front of the pulley take car for a drive give it hell then recheck the marks,, if if they have moved then things are spinning under load
 
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