It started as a breif hesitation when accellerating, generally in 3-5th grear from around 2500-3000 rpm. I Seafoam'ed the car and changed the plugs. The issue continued to slowly worsen and an additional Seafoam treatment didn't make a difference. Under the same circulstances there is now a very noticable engine rattle and a loss of power for a second or two before recovering. I've read the threads regarding the timing chain "death rattle" and this doesn't seen to fit the descriptions. I have a 2008 MCS with approximately 50,000 miles running nothing but Shell Premium fuel. It has a JCW CAI, a Miltek exhaust and a "Jan" tune, along with a mess of suspension changes. Any suggestions?

 

It almost sounds like the problem I had. I have a 07 mcs and it seemed like it would cut out for a second under hard acceleration, I took it in and it turned out to be the fuel pump.

 

Thanks. Any engine rattle in your case? The other odd thing is there are not engine codes display on the OBD2.

 

No, I didn't have any rattle, also I didn't have any error codes either.

 

I recently had a similar experience. Hesitation upon accelleration and the rattling/growling sound mostly in the first 2-3 miles of driving. I had an oil change and the sound has not reoccurred, but the hesitation has. 08 MCS- 67,000 miles. I suspect fuel pump issues.

 

Thats strange as when my wifes 09 MCS HPFP went out there were all types codes

 

Could be carbon buildup leading to hesitation and ping at lower rpms.

 

HPFP or carbon, seems like every MINI that isn't a 2011 need that pump replaced, thats my bet (mine has at the dealer now a week for similar problems getting it's HPFP replaced)

 

This is a good statement in my opinion.

My dealer would not replace my HPFP because I do not have the symptoms. With carbon, you may have to pay because they would likely blame bad fuel.

I wish they just did a recall for the HPFP and the chain tensioner but they are real cheap.

 

Do be careful - that rattle does not sound encouraging at all. Whether it has a mechanical origin, or is detonation, the consequences could be severe.

Can you temporarily revert to the OEM map, and see if that changes the symptoms?

Sorry to preach to the choir.

Kind regards,

Charlie

 

my 09 is doing the same thing. rattles at start up, goes away after warming up then in 3 or 4 thru 6th gear if i lay into the throttle it seems like it coughs once in a while. ideas?

 

Thanks for all the suggestions. I dropped it off at the dealer this morning. The Service Manager, whom I know and trust, suspected the timing chain. Thankfully it's just under the 50k mile drivetrain warranty. I'll let you know how it goes.

 

Good news! Turns out that sometimes it is the simple stuff. The tube/hose that goes from the air box to the Mass Airflow Sensor was loose. The large hose-clamp was loose so when the engine was experiencing a lot of torque during hard acceleration, a gap in the connection would open up causing a sudden loss of vacuum. The engine would run really lean for a few seconds causing some bad knocking. This settled the engine which closed the gap and everything was fine.

 

Well, now I'm hearing a slight rattle at btw 2000 and 3000 RPM when accelerating on my '07 S R56.

I've had the timing chain rattle before, with the subsequent replacement of the tightener, and whatever else was called for.

That sound was different.

I've also had the HPFP replaced about a year ago, and this seems more similar to that. Although previously it threw a code, and so far at least that has not happened. Maybe I'm just more attuned to it and sensing it before the code goes.

Last time this happened I recall it was one of the first really cold days of the year. It so happens that we've had our first frost. Although I see that everyone above was writing in May, so I assume that is coincidental, if indeed that's what's going on.

I am no longer under the original warranty, so I've been taking it to another shop. They are going to look at it tomorrow for me. However, when the HPFP was replaced last time I was told that they had put a special ten-year warranty on this part because it is a known issue. So I may be back at the dealer depending on what my shop finds.