My 1990 190E 2.6 failed the California smog exam. Actually, the tech said the emissions were okay, but that the vacuum was not. He pointed out a tiny hose that comes off the top of the air cleaner and--he said--should run into the back side of the tube holding the dipstick for checking engine oil. There is a small, almost pin prick sized hole here where something might once have been inserted.

This seemed strange to me, so I contacted the local MB dealership, who told me the hose connects to something under the air filter assembly. I removed the air filter assembly, but could not find anyplace missing its hose!

Where does this hose go? I first noticed it off just after I bought the car a year and a half ago, when I removed the air filter to reattach the throttle cable. Is this enough to throw off the vacuum readings? Or is it a vacuum hose at all?

The car runs fine; it misses a little upon first being started, but soon settles in (new plugs needed soon). Any ideas? Need to get that new sticker on the liscense plate before someone with a ticket book notices!

Thanks.

That hose is only there in the event that the fuel pressure regulator fails. If it does, the fuel goes from the back of the diaphram into the oil system via that hose.

In short, it will not change the emissions at all.

You may want to post the readings...This will give us an idea of what is wrong.