Hi Seed,

The dual striped line is Volvo OEM for vapor (vacuum) line in different diameters. Vapor being caustic to non vapor vacuum line. The blue striped line is made more resilient to caustic petroleum vapors.

The line you describe connects between the larger port on the dual vapor valve (Dunno hhhhwut to call it) atop the EVAP charcoal canister and routed from there to a port on the throttle body. The larger line is for when the throttle is open (engine not at idle) to draw fuel tank vapor using engine air intake vacuum. Though the fuel tank builds pressure about any time. More so when it is warmer and when the gasoline volume moves around as your drive your 1991 Volvo 240.

There exists a second, smaller diameter, vacuum line that connects to that same valve atop the EVAP canister that connects to a smaller diameter throttle body port that (I guess) draws vapor from the EVAP canister and into the engine air intake.

The EVAP system is something similar to how engine oil sump vapors are drawn through the PCV system, yet PCV routes more vapor volume using engine air intake vacuum. Though like EVAP, when the engine is on, oil sump vapors push outward with the PCV and engine air intake vacuum to guide the oil sump vapor to escape through the PCV and consumed by the engine.

The valve atop the EVAP canister can get a little stuck. It is sort of a tough valve. I used some brake parts cleaner to ensure vapor would pass through the small and large vacuum line ports at idle and engine run (not at idle).

Hope that helps. Thank you for the writer warm-up. Though nothing to write today.

Enjoy the images and you and Phil Machine Man and everyone enjoy a wonderful happy Friday and an even better weekend!


EVAP Canister. Had to remove to replace the 30+ year old factory installed plastic zip tie straps.
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EVAP Canister. Another view.
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Dual blue striped vapor line (or hose) section between PCV Oil separator breather box and the flame arrestor (trap) housing. This vacuum line as they all do becomes brittle. Other auto line or hose makers also make vapor line for PCV and EVAP yet myay not be as durable as what Volvo sells by the foot or centimeter.

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Now it's utter regrets leaving WA-state every single moment since OCT2015. Harassed there or here? Rather there.
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MO-state is awful. And here come the malodorous summertime. Cold temps here tamps down the odor. Driving through the St. Louis 'burbs, you can smell the many dog owners and their yards needing a cleanup. Awful. For about seven months or so.

Hope that halps.

Buttermilk Boy likes Buttermilk. Dairygold brand in WA is way better than Prairie Farms brand here.
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