Hi,

Just 2 days ago I completed the break in on Dinah...there was much rejoicing as I experienced spirited acceleration.

Just 1 day ago I was driving to the MVA office (DMV everywhere but MD) to register Dinah and the ride gets really rough. I wasn't doing anything funky, just cruising along on 695 with the top down. My first thought was "tire". I look at the speedo and see the DSC light is solid yellow (no, I didn't turn it off). The SES light was on too. The car is running but it's surging. I felt like I was losing power, then it would catch and go, then run normally, just lurching along. I pull off at the next exit and whip out the manual, which advises me to "get thee to a dealer". The car was idling fine.

I detour to MINI Towson and they send me on my way with a MCSCa. I call later and they were still trying to figure out what all the error codes meant, and my SA tells me they may have to e-mail MINI North America for advice. Great...

Today he tells me the problem is a bad MAP sensor. I looked online but I still don't understand what it does or how it caused my problem. Can someone enlighten me please?

This is the 2nd time in the shop for Dinah...she's not even registered and I haven't even made the first payment. At least I'm getting used to driving the auto-stick (that's what they gave me last time too).


Paul

 

Sorry to hear about your problems

 

the MAP sensor is the 'manifold absolute pressure' sensor. On turbo cars it measures the amount of pressure and/or vacuum in the intake stream and turns that analog measurement into a digital output for the computer. On a turbo car you could get the car to make more boost (sometimes, depending on the car) by simply putting a resistor orifice inline. on our cars it more than likely is just used to calculate the amount of fuel needed... which would cause the stumbling and everything if it was messed up. I wouldn't worry too much... they are a sensitive sensor and can be missed when faulty. Most likely once this is fixed you'll never have the problem again.

 

The MAP sensor is used to measure the amount of air being pulled into the engine in order to determine the amount of fuel needed. A MC has one, a MCS has two. these are also used to measure barometric pressure, and each also has a temperature sensor measuring the temperature of the incoming air. The engine computer is able to calculate the density of the air from these inputs, and meter in the proper amount of fuel. A set of oxygen sensors sit in the exhaust stream after combustion to measure remaining oxygen, then this information is also used by the engine computer to precisely trim the amount of fuel. When the MAP (or TMAP, for temperature and manifold absolute pressure) sensor fails, the computer has to make a determination if the sensor is giving false information. If it is, the computer will 'ignore' that sensor and make calculations based on other sensor inputs to best approximate how to deliver fuel. This is not always perfect, and in the case of intermittent sensors, the computer will switch from reading the sensor to ignoring it with an attending hiccupping in performance. Either way, the ECU will shine the check engine light and store a code or two to alert the driver and the tech as to what is going wrong.

 

Yah, give them time to get it right. If it happened this soon then you probaly got a dud of a sesor to start with.

 

What was the first reason you had the car in?

 

The "boot open" switch was bad. It would show the boot open even when it was closed.

Paul

 

Thanks for the thorough explanation. I wonder why the DSC light came on too. I'll be sure to ask about this when I pick her up.

Paul

 

The DSC light will come on in instances where an engine fault can impair the DSC. Since the DSC not only involves the braking system but the engine throttle as well (it's called torque management in the DSC's case), a problem that effect driveability can muck around with the DSC. In addition to cutting back on the throttle during wheelspin (which everyone eventually complains about ), the DSC can actually increase throttle opening (engine torque) in some cases. For example, if you hit a slippery patch while decelerating and braking, the DSC will release the brake on the slipping wheel. However, if you are in a lower gear and the engine is also contributing to the braking ('engine braking') to the point where it's preventing that particular front wheel from rotating again and regaining traction and control, the DSC can actually 'step on the gas' enough for this to occur and modulate the various braking forces to help save your bacon. When you have a problem that can interfere with the smooth application of engine torque (say electronic throttle control, misfiring, etc), the DSC is disabled in order to, well, save your bacon.

 

Cool...thanks!

 

Mine went in at 200 miles with an SES light, they claimed it was a MAP sensor so they replaced it. Then the light came on 50 miles later. After taking it back again it was a fuel pressure regulator that was putting out too much pressure (70 psi vs 55 psi). Mine ran poorly as well but didn't do the surging as you describe it.

Good luck

 

Here's the diagnosis, straight off the invoice. I don't understand it all, but someone may find it interesting.

1330 DSC LIGHT AND SES LIGHT ARE ON WARR FAUL CLT P0107 MAP SENSOR INTAKE, AND 5E19 CAN DATA FAULT INTAKE MAP SENSOR IS NOT READING RIGHT MAP SENSOR ON SIDE ON CLY HEAD IS BRING CAN LIN DOWN, REPLACE BOTH MAP SENSORS

They replaced the intake pressure sensor and the coolant temperature sensor. MINI US says it's not a common problem so hopefully it was just a fluke and stays fixed.

Paul

 

Fixed. Motor on!

 

Fixed!! Good, chalk it up to experiance and keep going sounds like you're on you way to happy days, the breaking was not entirely coincedane in my opinion. my be it is this sensitive sensor needed to be pushed before it failed, now its fixed, its a rare issue but you should be running smoothly here on out, glad to hear everything worked out.

 

at least you have warranty