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Charcoal Canister, Fuel Pressure Regulator, Purge Valve, P0440

xtrattitude4u writes: 

“98 s70 2.4l N/A
I have a clogged charcoal canister. As a result no vacuum makes it through to my fuel pressure regulator. What harm would it do to bypass the canister by connecting the two lines together until I can get a new one?”

EVAP diagram charcoal canister

“I really hope that I don’t still have a rich mixture problem. I did have a CEL of rich mixture a few months ago, but after replacing front O2 sensor and MAF it went away. I have also done a stage 0 tune and just about everything else that could fix a rich mixture problem. The only thing it might be is the injectors, but that sounds unlikely.

Just to minimize confusion, I have made this diagram to show how the system is connected. The hoses circled in purple are the ones I hooked together, providing the FPR with vacuum. I got at LEAST 50-60% better MPG after doing this. The slashed lines are fuel lines. I can’t believe I finally achieved great MPG by accident, only to discover it’s a false hope. Bummer.”

jblackburn asks:

“I’m glad you figured out what the cause of it was. I’m on the path of trying to track down my bad gas mileage – I have already replaced both the ECT sensor and FPR, MAF, and I’m sure something else I’m forgetting all at different points on my car when they crapped out.

Where IS the charcoal canister on your car? Though we have a similar model, I think we may have a different emissions system, which is why I was hesitant to comment on any of your posts before.

But is it safe to run like that?

Permanently, no. The EVAP system serves to let off the fumes from the gas tank that build up. I’m rather surprised you haven’t got a code for it before.

I left a gas can with the caps on once in the summer sun after filling it and deciding I’d mow the lawn the next day, and I guess it swelled up and burst. The charcoal canister/purge valve are to let the fumes out of your gas tank that build up in the heat, or in keeping fuel sealed in there.”

Bypass charcoal canister?

1 Comment

have a problem with my volvo 850 turbo import no fuel coming through, car will start sometimes but wont idel, and the air hoses to the turbo have slight bit of oil coming out of joins. what would the problem be and how to fix

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