After reading Greg’s discussion of cleaning his vacuum control valves on the
evaporative emission control system, I pulled all three off my US '86 SIII
the other day to do the same. After soaking and cleaning I couldn’t get the
powered one (found on the engine side of the fender well below the air
cleaner) to work. You can hear and feel it clicking when power’s applied to
it. Peeled the rubber boot off and found one of the wires was cleanly
broken from its terminal, even though it wouldn’t pull out of the boot. If
you’re suffering from the dreaded whoosh on opening your tanks, particularly
check out the action of this valve by making sure you have power to both
terminals and can feel or hear it operating.
you’re suffering from the dreaded whoosh on opening your tanks,
particularly
check out the action of this valve by making sure you have power to both
terminals and can feel or hear it operating.
My whoosh is vapor ESCAPING from the tanks. The tanks are pressurized. Is
this normal???
Dr.Michael E. Rothman
'87 January build Series III USA
Princess Margaret
Tom: this must be a US spec. part; I don’t believe that either of my cars
have such a valve; can you describe it more exactly?
Gregory----- Original Message -----
From: Tom Golodik tgolodik@cybernex.net
To: xj@jag-lovers.org
Sent: Thursday, September 09, 1999 6:39 PM
Subject: [xj] Gas Tank Whoosh
After reading Greg’s discussion of cleaning his vacuum control valves on
the
evaporative emission control system, I pulled all three off my US '86 SIII
the other day to do the same. After soaking and cleaning I couldn’t get
the
powered one (found on the engine side of the fender well below the air
cleaner) to work. You can hear and feel it clicking when power’s applied
to
it. Peeled the rubber boot off and found one of the wires was cleanly
broken from its terminal, even though it wouldn’t pull out of the boot.
If
you’re suffering from the dreaded whoosh on opening your tanks,
particularly
check out the action of this valve by making sure you have power to both
terminals and can feel or hear it operating.
No. See the thread about cleaning the valves. There should be no sound
whatever on opening the caps.
Gregory----- Original Message -----
From: Dr. Michael E. Rothman mrothman@megsinet.net
To: xj@jag-lovers.org
Sent: Friday, September 10, 1999 6:05 AM
Subject: RE: [xj] Gas Tank Whoosh
you’re suffering from the dreaded whoosh on opening your tanks,
particularly
check out the action of this valve by making sure you have power to both
terminals and can feel or hear it operating.
My whoosh is vapor ESCAPING from the tanks. The tanks are pressurized.
Is
this normal???
Dr.Michael E. Rothman
'87 January build Series III USA
Princess Margaret
No. See the thread about cleaning the valves. There should be no sound
whatever on opening the caps.
Gregory"Dr. Gregory Andrachuk" MGB@UVVM.UVIC.CA wrote …
Gregory -
Beg to differ with you on this one. The whoosh perhaps may be part of
the US spec. The way things are together on the SIII US cars no vapors
are allowed to vent directly to the atmosphere and the burn off of
collected vapors is timed so as not to interfere with cold start up
emissions. Having a 2 lb. rated check valve in the vapor collection
system guarantees at some point there will be pressure ( whoosh value )
in the tank(s) but if all is well 2 lbs or less. As to whether the check
valve operation is affected by pressure on the tank side and suction
from the intake side I don’t know, it has always been assumed (
dangerous ) to simply be tank pressure, but one of our fellow listers
claimed he got rid of all whooshing by drilling out the electronically
controlled purge valve on the inner right fender. This would create a
positive flow whenever the motor was running. Perhaps he removed the
check valve as well ? Others have sworn, and as Tom Golodnik is posting,
to have three valves while both my '83’s only have two. The parts book
does show an earlier cars vacuum controlled valve on the intake side
that seemingly serves the same function as the electronically controlled
valve. Why there would be both on a car is a mystery. The electronic
unit would have replaced the vacuum controlled one, yes ?
Whooshing here seems more temperature dependent than anything else.
Changes in ambient air temp from cool garage to sunny streets seems to
cause it. Overall it is probably a 50-50 split to have whoosh or not
when popping open a fuel cap. Slings and arrows aside thought this might
be of interest.
Paul, I think I agree because all US-spec cars I’ve owned whoosh, with a
force that would fit a 2lb or so pressure. They do this more as their
tanks approach empty. These cars are 3 Hondas and 1 Volvo. I know the
systems for Calif must not allow vapor release, which is why our 76
Volvo was sealed so tight we had to stop and open the gas cap upon
reaching 7000ft elevation.
Our Jag has not been driven enough for me to comment on its whooshing,
and judging from the cracks in the gas-cap rubber seals, I wouldn’t be
surprised if it leaked like a sieve.
No. See the thread about cleaning the valves. There should be no sound
whatever on opening the caps.
Gregory
Gregory -
Beg to differ with you on this one. The whoosh perhaps may be part of
the US spec. The way things are together on the SIII US cars no vapors
are allowed to vent directly to the atmosphere and the burn off of
collected vapors is timed so as not to interfere with cold start up
emissions. Having a 2 lb. rated check valve in the vapor collection
system guarantees at some point there will be pressure ( whoosh value )
in the tank(s) but if all is well 2 lbs or less. As to whether the check
valve operation is affected by pressure on the tank side and suction
from the intake side I don’t know, it has always been assumed (
dangerous ) to simply be tank pressure, but one of our fellow listers
claimed he got rid of all whooshing by drilling out the electronically
controlled purge valve on the inner right fender. This would create a
positive flow whenever the motor was running. Perhaps he removed the
check valve as well ? Others have sworn, and as Tom Golodnik is posting,
to have three valves while both my '83’s only have two. The parts book
does show an earlier cars vacuum controlled valve on the intake side
that seemingly serves the same function as the electronically controlled
valve. Why there would be both on a car is a mystery. The electronic
unit would have replaced the vacuum controlled one, yes ?
Whooshing here seems more temperature dependent than anything else.
Changes in ambient air temp from cool garage to sunny streets seems to
cause it. Overall it is probably a 50-50 split to have whoosh or not
when popping open a fuel cap. Slings and arrows aside thought this might
be of interest.
This may sound like blashemy, but I just pulled the canister check valve off
and drilled it straight through. Closed system, no big deal.
Now, for another “All comments requested”!
My car has a sort of acrid smell, kinda like exhaust smell but not quite. I
don’t think I’ve smelled it around any other car. Certainly not around my
'85 XJ6.
Any takers?
BTW, has the Bell stainless exhaust system, no middle cat, and a functioning
(i’m pretty sure!) front cat.
In reply to a message from Bob Hudson sent Sat 9 Nov 2002:
there was a whole dicussion on this recently. You can blow through
the valve with a small amount of effort one way, and can suck the
other way.
this is a link to the discussion. http://forums.jag-lovers.org/tv.php3?
eNolyDEOgDAIRuHbdFb4odiEw5joUAdNdOnxDXT68t7zdu/3cY6y+7jK5wCIqAXCAaMm
NZEFiclEA7WchihZYYlOtpxM3H7ImhkD–
Russell Barnes
Mississauga, Ontario, Canada
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
Right, and I’'ll just add that every emissions-controlled car I’ve owned
whosshes when the gas cap is opened – the more empty, the more whoosh. If it
whooshes a lot when full, well there may be a problem.–
Alex
79xj6L SII (BRG + wires)
86xj6 SIII (Black)
61 Sprite MkII (Red)
Menlo Park, Calif.
In reply to a message from Bob Hudson sent Sat 9 Nov 2002:
there was a whole dicussion on this recently. You can blow through
the valve with a small amount of effort one way, and can suck the
other way.
Thank you, Russel. This is the ideal description on how the valve should
work.
Blowing, with some resistance would simulate slight overpressure in the
tanks as fuel expands (thank you, John!), while sucking simulates
underpressure in the tanks as fuel is consumed. Allowing air to be
sucked from the vacume source (crankcase ventillation tube) through
cannister to tanks. Voila, very little whoosh, either way.
Bear in mind that the engine vacume through cannister is rather low, and
should be easily overcome by tank vacume. That said, nobody has actually
mentioned measuring vacume at the valve, or at the relecant cannister
opening. So there I’m sort of guessing. But the way everything is hooked
up, and with a 3mm restriction in the vacume line to cannister at the
crankcase vent pipe… A restriction which, BTW, must be easily
clogged??
What beats me every time I think about it: How do they make the valve
work that way??