Gas Fumes 1989 300SE
 

The car will not be used for a number of days and when it is put in the garage after even a small trip it has a very strong odor of fuel. The odor can also be detected inside the car while driving. No obvious leaks or drips and has been to the shop twice and no problem found.

Dave,
The EHA, electro-hydraulic actuator on the fuel distributor is often overlooked. It will seep enough gas to bug you but not enough to reach the ground. Remove you air cleaner and see if your fuel dist. has a pinkish/yellowish hue. If so the EHA could be the culprit. (EHA, black box on side of fuel dist. with a two wire connector)

if the injectors are leaking, they leak into the intake and run downhill to the plenum under the airflow meter. it's very common for the eha, fuel dist and injectors ALL to be leaking. good luck, chuck.

The EHA is made from Bakelite, I believe, and can develop hairline cracks from years of heat. You cannot detect them sometimes, but the fuel seeps out nonetheless. I had a particularly difficult time finding the source of a persistent fuel odor in my 190e many years ago. The EHA appeared OK, but when I changed it, the smell was gone and the car ran better.

Thank you for your help. The EHA unit was wet with gas. This looks like something I can replace myself. Two torx screws and a plug.

Yes, it is easy, but be aware the fuel you will release is under some pressure. Have a good rag handy. Also, make sure you use ONLY the correct MB O-rings to seal the 2 passages. No other O-ring I was able to find from any other source was quite the same. I had some last for a few weeks, but ultimately the MB ones are best. Don't lose them. Leave a clean rag underneath during reassembly to catch the errant one.