Charcoal canister, Gas smell HELP!!
08-22-2011, 03:21 PM
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Charcoal canister, Gas smell HELP!!
hi all,..
recently i noticed a very unusual strong gas smell coming from my 94 runner. just an hour ago as i got home and turned the engine off, i noticed a 'humming' sound coming from the charcoal canister. also noticed that the vent hose coming from the bottom of the canister was dripping gas. today @ a red light a driver pulled next to me and pointed out that she could see and smell the fumes coming out the hose. that scared that crap outta me. luckily i made it home safely and that i live next to fire department. is anyone else having this problem? any help will be greatly appreciated.
recently i noticed a very unusual strong gas smell coming from my 94 runner. just an hour ago as i got home and turned the engine off, i noticed a 'humming' sound coming from the charcoal canister. also noticed that the vent hose coming from the bottom of the canister was dripping gas. today @ a red light a driver pulled next to me and pointed out that she could see and smell the fumes coming out the hose. that scared that crap outta me. luckily i made it home safely and that i live next to fire department. is anyone else having this problem? any help will be greatly appreciated.
08-23-2011, 09:23 AM
#3
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1st, DON'T DRIVE THE VEHICLE IF YOU HAVE A GAS LEAK! There are MANY sources of ignition in the engine compartment. Anyone who has witnessed a fuel-fed vehicle fire would never drive a vehicle with a fuel leak. And fuel smell means there definitely is a fuel leak.
2nd, also check the fuel pulsation damper, which is in that area. Many times people have mistakenly believed the charcoal canister was leaking, when it turned out to be the pulsation damper. See this earlier post from http://www.toyotanation.com/forum/sh...&postcount=23:
3rd, if it IS the charcoal canister, check for hose routing and diagnosis steps here:
http://personal.utulsa.edu/~nathan-b...76evaporat.pdf
2nd, also check the fuel pulsation damper, which is in that area. Many times people have mistakenly believed the charcoal canister was leaking, when it turned out to be the pulsation damper. See this earlier post from http://www.toyotanation.com/forum/sh...&postcount=23:
This is one that's starting to come up more frequently:
Most common fuel leak spot on the 3vze is the fuel pulsation damper, a little disk with a plastic cap stuck on the back end of the passenger side fuel rail. It's dangerous because it drips fuel onto the intake manifold, where it can create some good-size pools, then overflows onto the exhaust crossover which ignites it. Some very nasty fires have started as a result.
Usually manifests as a fuel vapor smell in the cab.
Check for it by jumping +B & FP in the check connector and turn ignition on (but don't start it). That will run the pump and pressurize the fuel rails. Just reach around under the back of the plenum on the passenger side, inboard of the valve cover. About an inch inboard of where the passenger side heater hose comes out the firewall, also a couple inches down and a few forward. Prob a good idea to locate it before pressurizing the fuel lines.
They're pricey for their size - about a hundred bucks. Best price will be from Gary Smith, the parts manager of Toyota of Newnan, GA who offers TN members a 30% discount and actual cost shipping, plus a buck or two for materials cost. Phone is 678-854-9601. Or try 1sttoyotaparts, but I couldn't find the damper in their catalog, so you may have to call them. There are reports of aftermarket parts not fitting, so best to go dealer on this item. (Aftermarket not much cheaper than Gary, anyway.)
Don't forget to get new copper/aluminum crush washers.
EDIT - See this great thread for part numbers and tips on replacing:
https://www.yotatech.com/forums/f116...ner-v6-186626/
It's like a shock absorber for fuel pressure. Evens out the spikes & drops in pressure as injectors open and close, so the fuel metering remains accurate.
Thanks to yotatech members for these photos.
Most or all 22REs have pulsation dampers too, on the underside of the front end of the fuel rail.
Other somewhat common leak spots include injectors (including the cold start injector), the front or rear rubber portion of the fuel return line (front connects to the fuel pressure regulator which is front end of driver side fuel rail on 3vze, back end of fuel rail on 22re; back rubber section connects to fuel pump bracket on top of gas tank - the middle section of the return line is steel). Sometimes the metal fuel or return lines rust and develop leaks on top of the gas tank, which is the fuel pump bracket. If new copper or aluminum crush washers were not used on both sides of a banjo fitting when fuel line segments were disconnected, then the joints can leak. There are rare reports of the fuel vapor recovery canister leaking, but that isn't common.
DO NOT IGNORE GAS SMELLS - FUEL SMELL MEANS FUEL LEAK! There are MANY sources of ignition on a vehicle. No one who has ever witnessed a fuel-fed vehicle fire would ever drive a vehicle with a fuel leak. https://www.yotatech.com/forums/f116...ew-one-222309/
Most common fuel leak spot on the 3vze is the fuel pulsation damper, a little disk with a plastic cap stuck on the back end of the passenger side fuel rail. It's dangerous because it drips fuel onto the intake manifold, where it can create some good-size pools, then overflows onto the exhaust crossover which ignites it. Some very nasty fires have started as a result.
Usually manifests as a fuel vapor smell in the cab.
Check for it by jumping +B & FP in the check connector and turn ignition on (but don't start it). That will run the pump and pressurize the fuel rails. Just reach around under the back of the plenum on the passenger side, inboard of the valve cover. About an inch inboard of where the passenger side heater hose comes out the firewall, also a couple inches down and a few forward. Prob a good idea to locate it before pressurizing the fuel lines.
They're pricey for their size - about a hundred bucks. Best price will be from Gary Smith, the parts manager of Toyota of Newnan, GA who offers TN members a 30% discount and actual cost shipping, plus a buck or two for materials cost. Phone is 678-854-9601. Or try 1sttoyotaparts, but I couldn't find the damper in their catalog, so you may have to call them. There are reports of aftermarket parts not fitting, so best to go dealer on this item. (Aftermarket not much cheaper than Gary, anyway.)
Don't forget to get new copper/aluminum crush washers.
EDIT - See this great thread for part numbers and tips on replacing:
https://www.yotatech.com/forums/f116...ner-v6-186626/
It's like a shock absorber for fuel pressure. Evens out the spikes & drops in pressure as injectors open and close, so the fuel metering remains accurate.
Thanks to yotatech members for these photos.
Most or all 22REs have pulsation dampers too, on the underside of the front end of the fuel rail.
Other somewhat common leak spots include injectors (including the cold start injector), the front or rear rubber portion of the fuel return line (front connects to the fuel pressure regulator which is front end of driver side fuel rail on 3vze, back end of fuel rail on 22re; back rubber section connects to fuel pump bracket on top of gas tank - the middle section of the return line is steel). Sometimes the metal fuel or return lines rust and develop leaks on top of the gas tank, which is the fuel pump bracket. If new copper or aluminum crush washers were not used on both sides of a banjo fitting when fuel line segments were disconnected, then the joints can leak. There are rare reports of the fuel vapor recovery canister leaking, but that isn't common.
DO NOT IGNORE GAS SMELLS - FUEL SMELL MEANS FUEL LEAK! There are MANY sources of ignition on a vehicle. No one who has ever witnessed a fuel-fed vehicle fire would ever drive a vehicle with a fuel leak. https://www.yotatech.com/forums/f116...ew-one-222309/
http://personal.utulsa.edu/~nathan-b...76evaporat.pdf
Last edited by sb5walker; 08-23-2011 at 09:35 AM.
08-23-2011, 11:49 AM
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im sure its not pulsation dampener because i can see the gas dripping out from the hose that comes out from the bottom of the charcoal canister. i inspected the pulsation dampener and it appears to be okay. recently i had taken my runner to get my a/c lines replaced and i remember noticing that the mechanics accidentally broke one of the nipples from the (red) vsv. attatched to the nipple was a hose marked #5 that connected to somewhere below the manifold. i blocked off the end where the hose was attached to so i wouldnt have a vacuum leak. i am not sure if that vsv had anything to do with the canister. thanks for helping sb5walker
02-07-2014, 12:40 PM
#5
Reviving old thread here..
I was getting lots of pressure building up in my fuel tank, and I looked into it today. I ran through the FSM suggested diagnostics to determine if I have a faulty charcoal canister... I think I do. When I blow into the "Tank" line, according to teh fsm I am supposed to get free air flowing out of both of the other two locations, however on my canister the air blown into the tank line only escaped form the bottom fresh air line. However, when I pull air from the 'purge' line, I am able to pull out (mouth pressure) fuel vapors, and when I blow into the purge line the check valve correctly disables the air flow.
So, I ask, do I REALLY have a problem here? I don't really see how this will lead to the tank having so much pressure buildup...
I was getting lots of pressure building up in my fuel tank, and I looked into it today. I ran through the FSM suggested diagnostics to determine if I have a faulty charcoal canister... I think I do. When I blow into the "Tank" line, according to teh fsm I am supposed to get free air flowing out of both of the other two locations, however on my canister the air blown into the tank line only escaped form the bottom fresh air line. However, when I pull air from the 'purge' line, I am able to pull out (mouth pressure) fuel vapors, and when I blow into the purge line the check valve correctly disables the air flow.
So, I ask, do I REALLY have a problem here? I don't really see how this will lead to the tank having so much pressure buildup...
02-07-2014, 04:40 PM
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How much is "lots" of pressure? On a warm day, the vapor pressure in the tank will out-run the evap, so when you remove the cap you should get a "whoosh" of escaping vapor. (more so when warmer, and when tank is emptier).
I've never tested an evap, but consider placing your finger over the bottom drain when blowing into the tank line, to see if air escapes from the purge line. Otherwise, it sure sounds like it passes the test.
I've never tested an evap, but consider placing your finger over the bottom drain when blowing into the tank line, to see if air escapes from the purge line. Otherwise, it sure sounds like it passes the test.
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02-07-2014, 10:49 PM
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If you are getting a lot of pressure when you remove the cap then the there are two area to look at,
One is the vacuum line from the throttle body to the bi-metal valve to the evap canister.
Once the engine temp goes above 90f the bi-metal valve opens and allows a continuous vacuum (about 3 lbs) to the evap canister.
This purges the fumes from the canister and tank.
The line from the top of the tank runs to the evap canister.
The evap canister vent check valve gets plugged and stuck.
If fuel is coming out that it is more then likely that the vacuum from the throttle body is not keeping pressure from building up in the tank, Suggest check that first.
You can bypass the bi-metal valve altogether and run the hose straight from the throttle body to the canister.
One is the vacuum line from the throttle body to the bi-metal valve to the evap canister.
Once the engine temp goes above 90f the bi-metal valve opens and allows a continuous vacuum (about 3 lbs) to the evap canister.
This purges the fumes from the canister and tank.
The line from the top of the tank runs to the evap canister.
The evap canister vent check valve gets plugged and stuck.
If fuel is coming out that it is more then likely that the vacuum from the throttle body is not keeping pressure from building up in the tank, Suggest check that first.
You can bypass the bi-metal valve altogether and run the hose straight from the throttle body to the canister.
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