1992 mercedes 190E stalls when coming to stop and changing into second?

Question

Car stalls when coming up to a roundabout if i come down through the gears. if i go from 4th to neutral it doesn't always stall. If i accelarate hard then slow down it stalls. Removing the gas / petrol cap seems to fix the problem. There is a lot of suction whoosh when i undo the gas cap. My brother thinks i may have the wrong gas cap and need a ventilated cap not the one i have. Has anyone heard of this before?

Answer 1

There should be an evaporative emissions system on this car. It consists of a carbon cannister that absorbs fuel vapors from the tank. When the car is running, the canister is flushed with air into the intake manifold, where the vapors are burned with the fuel charge. If a vacuum forms in the tank, air is supposed to be drawn back in through the carbpm cannister. It sounds like there is a blockage between the tank and carbon cannister, or perhaps the cannister itself is clogged. You certainly can circumvent this problem by drilling a tiny hole in the gas cap, but that's illegal depending on where you are.

The most likely cause of this problem is a blocked vent valve. You can find this valve under the car, behind the left rear wheel. It's designed to open when there is a vacuum in the fuel tank, allowing air to be drawn into the tank through the charcoal cannister. If it's stuck, you will have a vacuum in the tank as fuel is pumped out. Do not eliminate this valve: if it's eliminated, then gas will be drawn directly into the charcoal cannister whenever the tank is full, causing flooding.

Answer 2

yes i used to have a car like this, try running without the petrol
cap off see if this is the problem.take your time round roundabouts etc, or the petrol will swill out.OR look if the breather pipe is blocked that could be it.

Answer 3

There should be a breather pipe on your tank, I'd bet it's blocked.