[Shotimes] Fuel vapor line issues (from TechSho)

[Carl Prochilo]

I thought this thread might be useful to post here.
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Mission complete. Here are some pics.

http://tinyurl.com/59x2u

One is a little blurry, but you can get the idea. The last picture
shows a cleaned hose coupler. The vapor flow back to the TB is clearly
metered by the small hole both at the coupler connection and then again
at the input to the CANP solenoid via a red inline coupler (no picture
of this one). In my case I have the solenoid removed. I still plan to
test the electrical connection to make sure the PCM driver is really
dead, but I have no reason to believe it is working. Bruce, you really
need to make sure your solenoid is working. And I don't mean to just
run to AZ and buy a new part. Test to make sure the 12V signal is
present in the connector when the car is warmed up.

Basically my situation is the same as Sergio's in that some white crusty
substance (no, I did not try to smoke it) clogged the inlet to the
T-coupling that you can see in the first picture. I chose that
particular connection, then tried to blow into the connector expecting
that to be fine but the hose back to the tank blocked. In fact it was
the opposite. The connection back to the tank was fine but the inlet to
the coupler was quite clogged. My little idea of putting a while
plastic baggy fastened by a rubberband over the fuel filler is adequate
to test blowing into the hose that goes back to the fuel tank to verify
that adequate flow exists with a second person.

Once I freed that restriction, no more fuel smell sensed using the
closed garage door test. Interestingly, there is still a good bit of
pressure in the tank even with the restriction removed.

Gary Morrell, do you know if this gas tank pressurization is correct
with say about 5 gallons in the tank, that opening the gas cap should
still produce some hissing in 80 degree weather. It would be good to
know how much pressure is normal under this situation. I'd love to be
able to meter this somehow.

Cheers,
Carl Prochilo
92 Ultra Red Crimson

Bruce Malachuk wrote:

Please take pictures when you do this if you can. I have a horrible gas
smell in my car anytime my car gets below 1/3 to 1/2 a tank of gas. Worse
now with the 155lph pump. My valve on the top or the tank works fine as I
checked it when I had the tank down. I sooooo want to fix that fuel smell
over the winter. Hopefully that will also fix the problem wioth MAX A/C
making the car smell like fuel too. Funny that my old 94 and 95 SLO's never
had that problem, just my 94 SHO.


Bruce Malachuk

-----Original Message-----
From: Carl Prochilo [mailto:gr8-@adelphia.net]
Sent: Saturday, December 04, 2004 6:29 PM
To: Tech-@topica.com
Subject: RE: Fuel vapor line question

Sergio, I'm almost ready to do the same procedure. The white residue be
typical for fuel evaporation. I have a feeling this situation is more
typical in older cars.

The one thing that should give you good indication besides the smell being
gone is how much pressure the tank has after the car has been running for
about 10 minutes. Also, I would assume that disconnecting the hose at the
TB should allow you to detect if the fumes are being pulled from the tank
into the intake.

BTW, the Ford factory service manual says that if you apply 4 psi into the
vapor hose going back the tank, and you have a pressure tester on the fuel
filler, you should be able to detect that same pressure reading.
Basically as you said it should be free flowing.

BTW, according the pics I saw in the manual, there is another 90 degree
bend by the right strut tower where all 3 hoses come into the engine bay.
Not sure if that spot will also be plugged with the residue.

Carl

Sergio Perfetti wrote:

I did some vapor line testing today. Checked vacuum from the TB to the
canister, good.

To check the lines from the canister to the tank, the Helms says to
use a hand pump to pressurize to 2.5psi. I blew into a gauge and it
was not much trouble to blow 2.5psi. So I skipped the hand pump. I
blew into the line from the canister to the tank and found it was
clogged. About 2 inches from the canister end of the line is a purple
plastic connector, rubber hose on both ends. Pulled the hoses off and
found some white powdery paste kind stuff in the purple connector.
Cleaned it with a Q-tip and some brake clean. Inside is a small
orifice that was still blocked. I found a small paper clip that fit
the hole, .028". I have no idea what the white stuff is. I tried to burn
it, but it didn't light.


Took the tank down enough to take the vapor hose off and plug it. Blew
into the hose from the front and found no leaks. Hooked the tank end
back up and blew into the hose and there's flow. So according to the
Helms all is good.

Now I just have to wait til the tank gets empty to see if the gas
smell is gone.