hello all !
i have a mini cooper s year 2006 and it has a weird problem.
the engine will kind of jerks like not enough fuel supplying for like 3-5 second and it stops then it will come back in another 5 minutes and so on.
so far what i confirmed and checked was : -

1.fuel rail (cleaned)
2.fuel regulator (tested with another same working mini with a working regulator)
3.injector ( cleaned and no leaking )
4.fuel pump ( i replaced it and it doesnt fix the problem )


P/S this only happens when i turn on the air cond ! and it happens on hot and cold temperature.

anyone out there experience the same problem or experts who knows how to fix or any infos please do help!

Thanks in advance!

 

I don't have this problem on my car. But it may not be a fuel issue. Check to see that none of the hoses or tubes aren't cracked or leaking. This could be happening if there is air escaping through an EGR tube or any of the other hoses running around your engine.

also, when you turn on your A/C, there is more stress on the accessory belt. Check to see that isn't slipping.

Not sure what else to look at without more detail.

Hope you find the problem and it's easy to solve.

 

It could be a "brain fart". Maybe your ECU needs to be refreshed...just a thought.

 

thanks for replying my thread ! will try it tomorrow first thing in the morning !

 

Did you put >91 octane gas in the tank from a reliable source? Around here, every once in a blue moon, a gas station gets caught watering down the gasoline... "bad gas" -- of course once caught, said dogs go to jail.

 

I think is bad gas too it alredy hapen to me after and new tank of fresh new gas it went and never came back

 

A/C clutch and/or compressor "locking up".

 

It happens to my car too. If I'm just sitting there at a stop light or something with the A/C on it go down and buckle then go back to idle every bout two minutes or so. I just learned to deal with it. Its a small car, small motor. I mean you can feel the difference when you drive with the A/C on so when the engine is idling it will have a big effect

 

My car used to do this as well. Solution was to put the car in a garage. I would also bring the revs up a bit in the morning, this smoothed out the car a bit. Its a cold start thing, nothing is broken with the car. Best remedy is buy good quality 91 oct fuel or higher. During the winter I buy 103 oct VP fuel in a 5gal drum and mix that in with the crappy pump fuel to raise the octane. Its not cheap but the car stays happy.

 

You didn't mention if this happens only at idle or if this is felt while travelling down the road. Have you noticed any corresponding issues with gas mileage ? It may not even be fuel related. Especially since it appears that you covered most bases, and have no other issues.

In cases like this, I usually begin with the most simplest, and inexpensive diagnosis/part replacement. Then go to dealer when all else fails.

You could inspect your plug wires (and plugs too). When additional voltage is pushed through a bad wire, or slightly cracked ceramic on a broken plug it will have similar sporadic beahvior. Check each wire all around from end to end for any fine black streaks. Or if you know someone with a MINI, swap them out for a quick test.

Absent those items having already been checked, I would refer to Robbybee's post. ECU may not be properly adjusting fuel/air mix for added load to motor when A/C kicks in. Dealer can re-flash to clear out any bugs.

 

alright thanks for everyone's attetion and helping me !

i diagnosed it with a scanner[OBD II] and it does not give any fault codes.
so what i did was i swapped everything i could from a same MINI right next to it. what i swapped was :-

1)fuel rail
2)fuel regulator
3)injectors
4)spark plugs
5)coil and also wires.
6)throttle body

everything i do still fails on me.
what i havent tried was the ECU reflash thingy and there is no vacuum or pressure leak.
i will try inspecting the a/c clutch or compressor and the belting like "hegira" posted befpre

P/S this happens when the car is idle with the a/c on !

again sorry for the LONG POST and thanks for those who posted and willing to help!
will update soon with any more good or bad results!!
Thanks All!