Cleaning throttle body and ''funny'' RPM when starting

smetol

I had disconnected the battery for a while and connected again just to realized i had some problems with start up my car.The car was starting at 500 RPM and dying,I had to really push the accelerator pedal to keep the car alive.I think also the fuel consumption was higher. Somebody advised to me the throttle body may be dirty so the proper cleaning is necessary.
So I did,to my surprise the throttle body was really black,full of sediment(it looked liked burned oil).
I reconnected the battery again and started the engine.The RPM's jumped to 1500 and after 10-15 seconds dropped to 1100 and stayed at this level.I drove for a test drive for about 2 miles and turn on/off the engine. The RPM dropped to satisfied 800RPM.
My question is:
Is it normal the throttle body is so dirty(the car is 2006,mileage 80 000 miles),what may cause the dirt.

The car is Suzuki Grand Vitara

biko

It's not normal but it's also not unheard of.
I did a write up on an old Volvo years ago and the TB was manky.
Then another write up for BMW and the TB was pretty fine to start with.

Make sure your oil is at correct level and the air filter is changed and the TB should stay pretty clean.

hi5

For emissions reasons the fumes from the crankcase, etc, are recirculated back in to the engine for combustion, over time some will settle on the throttle body.
As regards the jump in revs, when the battery is disconnected, it can sometimes take a few seconds for the computer to re learn.

walus

I recently cleaned a TB in my car (04, 90k miles) and it was very dirty. After such procedure the ECU needs to lern to control the TB again and it is best to start the engine and leave it idle until the radiator fan kicks in - you know for certain that the engine has reached its optimum temperature.