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| My 1988 LFX F40 build. (Page 46/68) |
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pmbrunelle
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AUG 01, 11:18 AM
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Since the introduction of OBD-II, you can't just vent the canister with a simple hole.
OBD-II requires the system be regularly pressure-tested to detect any leaks, which could allow for fuel vapour to escape.
Now there's normally a solenoid inline with the canister vent. When the ECU decides to test the system for leaks, it will (temporarily) close the vent solenoid, and see if pressure builds up.
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Daryl M
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AUG 01, 05:44 PM
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| quote | Originally posted by pmbrunelle:
Since the introduction of OBD-II, you can't just vent the canister with a simple hole.
OBD-II requires the system be regularly pressure-tested to detect any leaks, which could allow for fuel vapour to escape.
Now there's normally a solenoid inline with the canister vent. When the ECU decides to test the system for leaks, it will (temporarily) close the vent solenoid, and see if pressure builds up. |
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So how does the vapor get vented? Isn't the whole idea to prevent pressure build up in the fuel tank when the ignition is off? Is vapor routed through the canister, removing fuel vapor from air, then allowed into the atmosphere? Isn't that how the Fiero canister works?
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qwikgta
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AUG 01, 08:01 PM
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not wanting to start a fight, but, I have an LS3 in my 88 coupe. I went to Archies to have it installed and even helped out with the install a little. One thing I remember is that we removed the expansion tank that sits above the pass rear wheel and the charcoal canister that was in the engine bay. The gas tank now vents thru the metal line/hose that led to the charcoal canister and i put a small air cleaner on it. I smell no "excess" gas coming out of it and have had no issues driving the car this way for 7 years. Yes I understand its not helping the environment venting the gas tank to the air, but from a driving point of view removing it does not seem to have effected the engine at all. Another guy in my local club has the same setup and he routed the line on his to a homemade charcoal tank made from some lawn sprinkler parts. It seems to work and it looks really cool.
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Daryl M
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AUG 01, 08:38 PM
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For me, this is more a learning thing. The original Fiero setup is different from the setup on the 2013 impala. Making a hybrid of the two is interesting to me. It would be easier if I had a sketch of the Impala system.
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pmbrunelle
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AUG 01, 09:34 PM
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| quote | Originally posted by Daryl M:
Isn't the whole idea to prevent pressure build up in the fuel tank when the ignition is off? |
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Yes, we don't want the tank to become inflated.
| quote | Originally posted by Daryl M:
Is vapor routed through the canister, removing fuel vapor from air, then allowed into the atmosphere? |
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Yes
| quote | Originally posted by Daryl M:
Isn't that how the Fiero canister works? |
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Yes again.
With OBD-II, I suppose that vent solenoid is closed only long enough for the leak test to be performed. I don't think the pressure is held in long enough to cause problems. I don't know the specifics.
Sometimes, on an OBD-II car, when you unscrew the gas cap, you can hear a hiss.[This message has been edited by pmbrunelle (edited 08-01-2020).]
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Daryl M
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AUG 01, 10:08 PM
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| quote | Originally posted by pmbrunelle:
Yes again.
With OBD-II, I suppose that vent solenoid is closed only long enough for the leak test to be performed. I don't think the pressure is held in long enough to cause problems. I don't know the specifics.
Sometimes, on an OBD-II car, when you unscrew the gas cap, you can hear a hiss.
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Thanks for all of the good info. I'm learning a lot.
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Daryl M
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AUG 02, 11:33 PM
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After more research I found a vapor canister that has a vent solenoid incorporated in the canister. It fits several 2012-2015 GM cars like the Buick Verano and Chevy Cruze, etc . Does anyone know if the vent solenoid is normally open or normally closed?
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Rickady88GT
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AUG 03, 09:23 PM
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| quote | Originally posted by Daryl M:
After more research I found a vapor canister that has a vent solenoid incorporated in the canister. It fits several 2012-2015 GM cars like the Buick Verano and Chevy Cruze, etc . Does anyone know if the vent solenoid is normally open or normally closed? |
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They should be failsafe. On the newer cars they have a purge and vent solenoid. If the battery goes dead, or the car is not run for extended times, the tank must still be allowed to let the gas expand and contract. The solenoids work to suck the fuel vapor out of the canister.
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Will
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AUG 03, 09:23 PM
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Daryl M
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AUG 04, 02:03 AM
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| quote | Originally posted by Will:
Part number? |
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GM 13413447 22740537
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