Bob Lang and I have been having an offline discusion about carbon canisters and
the evaporative emissions recovery lines/system. I thought I'd share some of
the discussion since others may have the same problem (blocked evap. line from
the fuel tank to the carbon canister) and like me didn't know it. Appreciate
any feedback too, if anyone else has had this problem and how they addressed it.
Thanks
Bud
71TR6 CC57365
71TR6 CC65446
>>>>Bob,
>>>>The latest is:
RML: If the canister is "full", you might get excessive fumes - after all,
that's the reason for the canister in the first place. Evaporative
emission controls.
>>>>Checked the canister and it didn't seem full to me. No excessive fumes, it
didn't feel heavier than it should (gut feeling, nothing to compare it to), and
since the evap. line from the fuel tank was blocked I don't think it's been
getting vapor laden fumes to fill it up anyhow.
RML: I've heard, but never seen, folks that have a blockage in the can or the
lines to the fuel tank that allow negative pressure to form in the fuel
tank that is strong enough to cause the tank to collapse.
>>>>I do have a blockage in the evap. line to the tank. I took the line off at
the canister, removed the fuel cap on the tank and tried to blow through it.
Couldn't get any flow whatsoever. I didn't have time last night, but I'm going
to try and blow the line out tonight or Friday. Good thing I asked for a
compressor for my BD which I know is sitting in the back of my wife's car and
which I'll get today when we do the open the presents thing with my kids. My
plan is to unhook the line from the tank at the filler neck and maybe below the
tank (I think I remember there's a connection there) and then blow the lines out
with compressed air. Once cleared of the blockage (and assuming it's a
hydrocarbon based blockage) I thought I'd spray some carb cleaner in the lines
and blow that through them to clean them out further. What do you think?
Anything I should be careful about? I think the nylon evap. lines can take some
light pressure...can't they? Hopefully I won't split the line but if I do I
guess replacing them is not such a bad thing.
>>>>I had a fuel pump go out on me a few months ago (lever arm broke at the
pivot point in the pump) and I'm thinking that the blocked line and hence the
vacuum in the tank caused it to be over worked and contributed to it's early
demise. And again I'm keeping my fingers crossed that this is also the source
of my idle drop problem (e.g. the fuel pump can't overcome the vacuum in the
tank at low RPMs and isn't delivering enough fuel to the carbs causing the idle
to drop 100-200 RPMs below the set idle speed (850-900 until it can pump enough
to recover). Please tell me that makes sense. I have my fingers crossed that
clearing the line will solve that problem.
I may pose this to the list too to see what they think.
>>>>Thanks for the help.
>>>>Bud
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