Supousa

2006 SL500/130,000 miles. Owned since 2010. Drove off accidentally without gas cap. Ordered what I thought was OEM gas cap from Amazon. Got the cap and placed on. Gas smell permeated cabin. Most noticeable when sitting and next morning it’s as if someone poured old gas in the car. Smell would dissipate after driving. Gas cap warning light came on, followed by check engine. Brought it to Mercedes, they said it was charcoal filter and purge valve. Both replaced with used part as MBUSA no longer makes. $700. Left dealership and gas light blinks rapidly, then gas cap message, then check engine light on. Brought it back and they said guess that wasn’t it, will have to start from scratch. Asked for refund they denied. Brought it to independent who replaced gas cap via smoke test and said the cap wasn’t oem. Picked up and slight smell in cabin. $370. BUT, unlike last time where smell went away after driving, now it increases - to the point of dizziness and nausea. What’s next? Mercedes says the codes are just general, not specific. The independent said nothing about codes. How can I help? I feel like everything is an experiment and a guess.

ldeem

If I had this the next thing I would look at is the purge valve and charcoal connections, especially to the tank which may be inside the cabin. Its possible something is not installed correctly or the used part are bad. The smoke test should have found that.

Before anything get someone with proper STAR system to look at codes and see if there are any checks or readings to verify the fuel vapor system is working correctly.

One more - is it possible fuel spilled inside the inside the cabin when you drove without gas cap? Maybe just need to cleaning where fuel spilled?

6_Myles

If you are getting dizzy...I'd imagine you have a pretty significant leak somewhere....I'd pull some carpet panels in the trunk or interior panels on the inside and start looking around with a flashlight.