I am still learning the ins and outs on my 1980 450sl.Less than 50k The first time I start the car in the day,and start to pull away.I get some strange pinging type noises from under the hood.This happens only When the car is moving,and I give it a little extra gas.This only last a few minutes than all is fine.It will not make the noise if I am not moving.If I just give it a little gas at standstill no noise.Is this somehow emmissions related Help.Michael

Could possibly be you smog pump. Mine makes a little noise at start upthen is gone. I have be told it is normal.

start up noise.
 

Thanks for trying to help.Mine does not have a smog pump.It is a tri catalyst with ox sensor.Again thanks