Does anyone know if, on the M52 engine (2.8l single vanos version: M52B28), outside temperature is one of the inputs the ecu takes along with pedal position, engine temp, revs, maf, etc in order to control the spark, fuel and vanos?
The reason I ask is my temp sensor is knackered and reads a constant -40 degC, and being a yorkshireman I won't fork out for a new one unless I absolutely have to (personally I don't care how cold it is outside, but if the car does then, yeah).
Now the car doesn't run perfectly. I wouldn't call it lumpy, but the idle does give the odd "blum..... blum" about every 5 seconds or so, and at full throttle it occasionally seems to be rapidly coming on and off power between 4k and redline, as if it's missing or something. The dyno located in my pants would draw a slightly jagged torque curve rather than a nice smooth line. It only does this occasionally though, most of the time it's solid power right to the redline. By the way it's had the M50 mani treatment, but before you ask no there's no vac leak it was done properly.
I was thinking maybe the ecu thinks it's receiving extremely cold (and so, extremely dense!) air, and is misadjusting the mixture or something?