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Re: Check Valve Progress, tank pressure Posted by Gary Stottler [Email]  (#1463) [Profile/Gallery]
(more from Gary Stottler) on Tue, 18 Dec 2012 04:29:49
In Reply to: Check Valve Progress, Terry, Sun, 16 Dec 2012 09:26:12 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Hi Terry,
Thanks for the update! I haven't made much progress since last week, I'm in the middle of changing job assignments, so in that fun space of doing two jobs at once for a while, not to mention the holidays! :-)
I still haven't gotten the check valve barb out of the rubber extension of the plastic fuel line as I need to stabilize the kink in the plastic line with a sleeve to prevent further damage. I got the rubber hose off the tank's nipple, but it's still attached to the barb on the check valve - when I started pulling on that, the check valve housing separated into two pieces. I think it was just a glue joint that failed, which makes me think it might be repairable, but the metal diesel ones still sound like the best bet.
With regard to the pressure, all 99s I've ever had build high pressure in the tank (probably only 1 psi or less in reality, but enough to make the "hiss" when you open the cap). This is related to their way of controlling evaporative emissions - it's not until the pressure relief opens (not sure what pressure that is) the the fuel vapor in the tank can flow into the charcoal canister and then be drawn into the engine. The original evap rules in the EPA SHED test ("Sealed Housing Evaporative Determination") were pretty basic, and you could pass the test by just sealing off all the vapors for 24 hours or so, so I think that's what they did. You could probably either remove the pressure relief valve entirely and just let vapor flow to the canister all the time (which might shortly saturate the canister leading to fuel vapor smell from the canister), or a better bet would be to install a very small (0.010"?) orifice bypassing the relief valve (don't want to remove the valve completely, still need it to open if there's really a high pressure) so that the pressure bleeds down when the car is parked. A lower pressure valve would also be an alternative if you can find one.
Best,
Gary
posted by 50.48.10...
_______________________________________ Gary Stottler
, Sat, 8 Dec 2012 06:30:56, Wed, 12 Dec 2012 19:22:57, Tue, 18 Dec 2012 04:29:49 <-- Viewing This Message, Sat, 8 Dec 2012 06:19:20, Sun, 27 Oct 2013 11:30:32
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