Leaky EHA
 

I found the source of my sometimes gas-smell under the hood- I have a leaky EHA valve. Is there a way to tell if it's the valve it'self or the seals? I can't see any cracks but I know they can be hard to spot- the leak seems to come from under the unit near the electrical connector and at the join to the fuel distributor. I'd rather have to spend $2 to fix it than $200 :)

Confirm that the 2 Torx cap screws are tight. If so I'd suspect that the EHA valve is cracked and leaking gas. That was the case with the EHA valve on our 1991 300CE at 120,000 miles. You can try replacing the 2 green O-rings, but I doubt that they're the problem.

I have a used EHA from my car that should be working if you want to try it. Same part number. You would need to replace the o-rings. E-mail me for info.

EHA leak
 

I had that gas smell under the hood and changed out the o-rings on the EHA and it fixed it. Cheaper than replacing the EHA for sure.

It is almost never just the o-rings, but they are cheap and easy to replace, do them and see.