I assume the purge valve removes fumes from the tank? I am been having issues getting my economy up and adjusting lambda. I get the duty cycle dialed in while the purge line is disconnected. All is well. Then when hooked up, the car acts like it has a vacuum leak. Even after a long idle, etc.

So now I am driving around with the vac line pugged and the car is very different. The engine runs cooler and overall the car is more responsive. And economy is up, I am already over my usual average milage and counting.

Can I leave the line plugged?

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

Not good for the charcoal canister,

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Well my millage is now up to 18.3 from a 15 at best, usually 13 to 15. Also the issue of warm start up stalls is gone. It would fire up fine, but any load on the system (being in drive, steering, AC) would kill it if I did not baby the throttle.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

I'd suggest figuring out why there is so much vapor/ air going to that line in the first place. It sounds like something upstream isn't working properly.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I am guessing there is damage or breach of the purge line going to the tank. The tank itself seems to seal nice. When I open it, I get a rush of air outwards. Always have.

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car