Having a strange issue with my R53... periodically, while waiting at stop lights, the car will start chugging. I don't know how else to describe it. It's more consistent than a misfire.

Only code I have is for an evap leak, so my first thought is fuel system (P0442). I recently changed the fuel filter, so I suppose I could have missed a step or broken something in the process. Along with the fuel filter, the following other components have been recently replaced: spark plugs (JCW), spark plug wires (NGK), and tune (GIAC) for the 17% reduction pulley.

Once I get the car back up to speed, and stop again, the problem goes away. I may only see it once while driving, sometimes never.

Thoughts?

 

its just a quirk minis have. almost everyone has asked about it. nothing to worry about. mine does it sometimes at stoplights and quikly stops as soon as it started.


as for the code. could be just as simple as the gas cap not being on tight.

http://www.obd-codes.com/p0442

 

Well that is good to know, thanks for the info!

 

When I had issues with a drop in RPMS too low at lights...and an imperfect idle...progressed to a "stumble/stutter" at about 3200 rpm...worse on warmer days...
it was a sigh of the T-MAP and or MAP sensors going bad....
Might be worth it to yank it and clean it...if you do a Google search...you can find the BMW TIS info on how the system works, and the symptoms of a failure....
The r53 uses a R50 t-map, using only the MAP part as a sensor on the cold side, and a r53 specfic T-Map on the hotside, on the front of the intake....
Just to point out...I did not get that code...but the symptoms matched.....matched EXACTLY what the BMW/MINI TIS sheet describes as the symptoms on the sheet for a failing map/Tmap.....
I found the OEM parts for $77 each from a MINI dealer online...
Eminiparts.com..sister dealer to a vendor MINIpartsmass.com....
Some others also do a 15% discount on websales....
the aftermarket parts were as much as 3X the amount....so watch out!
The two part # are 12-14-0-872-679...hot side r53 tmap...on the intake
and 12-14-0-872-648 ..cold side r53 MAP+r50 t-MAP..next to the head/air-filter area..

 

Cool, thanks! I will do those just for the hell of it too.

 

I had the same exact problem recently. Then I dumped a can of BG44K (engine/injector cleaner - ) in my gas tank (on a full-ish tank, per instructions) and it went away. Not saying it's a magic bullet, but it worked for me.

 

Oops. Actually this is the BG44K product I used...

 

I can try it if the sensors don't fix it, I would hope its not the injectors though... they have less than 1000 miles on them (brand new JCW 380cc).

The car is closing in on 100k so sensors seemed more likely. Thanks for the info though, if sensors don't fix it I will give that a shot too. I'm sure it can't hurt.

 

Any update on this situation? Thanks!

 

Still happens about once every 20-25 starts. Changed out both MAP sensors and checked for loose plugs/plug wires. No codes, doesn't happen enough for me to really be concerned yet. At first I thought it only happened with clutch depressed but recently I was in neutral and it still occurred. Once moving again it was fine and didn't happen again. One other time the idle jumped to about 1k and stayed there.

Going to wait for a code before I worry about it.

 

Irritating.... I noticed that I went all winter without a stumble. Now that it's 80+ I am getting it more frequently, even after fresh plugs.

 

As Adam says:
Perfectly normal, perfectly healthy.

 

Was there ever a good fix for this?
I installed the Detroit Tuning BPV some time ago hoping it would resolve the problem but I still get this from time to time.

 

Anyone?...

 

I have had the same problem.....for years. Done everything I can think of, but it still does it every now and then. Lots of post on here about the problem....seems pretty common for most mini's.

I will pull up to a light, and the motor idles just fine. Then all of a sudden I can feel the idle start to get a little rough, and the AFR's start to lean out on my gauge....and the motor starts doing it's chug-chug-chug thing for a few seconds. The AFR's will go from a normal 15:1 to around 19:1......then after a few seconds, the idle smooths out...and the AFR's go back to 15:1 and all is good. So for some reason....the idle mixture is leaning way out, I think that's what's causing the chug-chug-chug idle. Not sure why the DME doesn't try to correct the problem by adding more fuel....I guess it finally does after 10-15 seconds.

Sometimes it will do it several times a day, but then it might go for weeks without doing it. Just one of those mini quirks I've come to live with.

 

umm.. 15:1 is already lean, even at idle. What are you getting under load?

 

14.7:1 is stoch.......so yes, theoretically it's ever so slightly lean. But every car I have ever checked AFR's on always idles between 14-15:1. More fuel efficient to run a slightly lean idle....with no downside at all. 15:1 is a perfectly good, and fuel efficient idle afr.

My WOT AFRs are in the 11:1 range.

What are you seeing for your Idle AFR??