98 v70 NA P0455 - my most loyal friend

[kahl]

Found another hose that was bad. This is up under the top turbo hose.

[98v70dad]

So today I built my smoker box. I decided to use my $35 harbor freight air compressor to push the smoke. Be careful if you do this. Even though the output is regulated air pressure, its not that accurate in the 1 psi range. To verify the pressure I set up a u-tube manometer and found that the pressure on the air compressor regulator was way off. I adjusted the the pressure accordingly and now should be good to go. We'll see what happens tomorrow.

[98v70dad]

Heres what I found withe the cheap pancake 3 gallon air compressor. I think the same results would occur with a more expensive or bigger compressor. With the pressure set as low as 1 psi the airflow is so slight that it wont blow much smoke. The needle on the regulated air pressure gauge stays pegged on zero until the pressure is at least several psi. I thought I would pass this info on so others wouldn't waste their time repeating it to learn the same thing. I also learned that a good aquarium pump is capable of producing several psi which is more than I want to use. My smoker box needs some work so I'll save that for another time.

While I had the purge valve disconnected and a long hose connected to the charcoal canister I decided to blow through the hose and see if I could learn anything. No amount of air ever met any sort of resistance and I could hear air escaping with each exhale. The hose was long enough to get down close to the back side of drivers side wheel wheel and that is where the air sound was coming from. I did this with the engine off and no key in the ignition. The air valve should have been in the closed position.

So, there's a problem there. I haven't suspected that part because it is less than 2 years old. I believe it was a part from the volvo dealer which made me even less suspicious of it. Its either failed or the wire harness fell off of it. I doubt that the hose came off, but I suppose that's also possible. I'm pretty sure I used hose clamps on it. I do remember that I had a tough time getting the connector back on due to its location. I remember that valve was a real PAIN to get on/off. I wish I didn't have to do it again.

[sleddriver]

Heres what I found withe the cheap pancake 3 gallon air compressor. I think the same results would occur with a more expensive or bigger compressor. With the pressure set as low as 1 psi the airflow is so slight that it wont blow much smoke. The needle on the regulated air pressure gauge stays pegged on zero until the pressure is at least several psi. I thought I would pass this info on so others wouldn't waste their time repeating it to learn the same thing. I also learned that a good aquarium pump is capable of producing several psi which is more than I want to use. My smoker box needs some work so I'll save that for another time.

While I had the purge valve disconnected and a long hose connected to the charcoal canister I decided to blow through the hose and see if I could learn anything. No amount of air ever met any sort of resistance and I could hear air escaping with each exhale. The hose was long enough to get down close to the back side of drivers side wheel wheel and that is where the air sound was coming from. I did this with the engine off and no key in the ignition. The air valve should have been in the closed position.

So, there's a problem there. I haven't suspected that part because it is less than 2 years old. I believe it was a part from the volvo dealer which made me even less suspicious of it. Its either failed or the wire harness fell off of it. I doubt that the hose came off, but I suppose that's also possible. I'm pretty sure I used hose clamps on it. I do remember that I had a tough time getting the connector back on due to its location. I remember that valve was a real PAIN to get on/off. I wish I didn't have to do it again.

You're safe with an aquarium pump. Even using an air brush compressor caused no damage in my testing. Remember the smoke machines the shops use.

The shut-off valve will be open with the key off. I had to plug the air vent connected to it so the tank would pressurize and I could fill the system with smoke. The only time the SO valve is closed is when the control unit calls for an EVAP test, I believe.

The small, PITA connector on my charcan was suspect so I cut it off and replaced with silicone hose. The large charcan hose is the infamous "J-hose". It was fine.

[98v70dad]

You're safe with an aquarium pump. Even using an air brush compressor caused no damage in my testing. Remember the smoke machines the shops use.

The shut-off valve will be open with the key off. I had to plug the air vent connected to it so the tank would pressurize and I could fill the system with smoke. The only time the SO valve is closed is when the control unit calls for an EVAP test, I believe.

The small, PITA connector on my charcan was suspect so I cut it off and replaced with silicone hose. The large charcan hose is the infamous "J-hose". It was fine.[/quote]


I found on another website that the industry standard for smoke box tester is less than 1 psi. I have no way to verify that but it feels right to me so that's what I was wanting to stick to. You need a high flow rate and a moderately low pressure, I agree that an aquarium pump or a air brush compressor is better suited for the task because they are designed to push some air even at low pressures.

Check the my latest thread on the shut off valve. CN90 explained with a great illustration that at least for my car the shut off valve has a check valve in it that does not allow air out of the system. It will allow air to be drawn in or shut off for the leak down test but it never lets air out. I believe there are other configurations where the check valve may be a separate part. So, in my case, I should never be able to blow air through the shut off valve and I am able to do that ... I can hear it flowing out (it actually quite loud if the engine is shut off). Its buried, as you know, so I can't see it but I'll dig into it this weekend when I have some time and find out what is wrong.

I'm toying with mounting it in a more convenient location under the hood if there is space. I don't have a turbo so there should be some open space I could use. I don't like having to work in the space they picked for it. I have neck problems and it aggravates that.

[sleddriver]

CN90 explained with a great illustration that at least for my car the shut off valve has a check valve in it that does not allow air out of the system. It will allow air to be drawn in or shut off for the leak down test but it never lets air out. I believe there are other configurations where the check valve may be a separate part. So, in my case, I should never be able to blow air through the shut off valve and I am able to do that ... I can hear it flowing out (it actually quite loud if the engine is shut off).

I posted a detailed diagram + thorough system description previously. I also thoroughly described the methods I used to slay this dragon.

Not sure about CN90, but there is no check-valve in or near my SHUT-OFF valve, located next to the CharCan. With the key off, the valve is OPEN and you can blow right through it. That's why I needed to plug it to pressurize my tank + CharCan. Though liquids are incompressible, they do expand and contract with temperture, gasoline included.

Here in the Tx Summer, it'll be around 105°F in the shade. In the Sun, it'll be more like 130°F (Solar Heat Index). The asphalt will be close to that same temperture. You go to fill up. The gas is stored in huge tanks buried in the ground where it's about 72°F. So you pump 17ga. of cool gas into your hot tank, and it begins to expand. As its temp. rises, the more it expands. So where's the pressure going to go if there IS a check valve, preventing it's escape? When the vehicle is running, engine vacuum is pulling vapors from the tank, into the intake.

So what happens when you pull into a HOT garage, with a full tank of expanding gasoline, and turn off the motor? That liquid gas is still expanding. Will it pressurize the tank? No. The SHUT-OFF valve is OPEN when the motor is off. So the expanding vapor rises through the vent line, into the Charcan and out the VENT, into the atmosphere.

It'll take HOURS for the tempertures to equalize because now your car in inside an already HOT garage, with the door closed, The exhaust pipe is one very long heat pipe slowly drawing heat away from both the CAT and exhaust manifold and engine block. Part of that exhaust pipe will be radiating heat to the drvr side of the tank, increasing the temp of the gasoline there.

Further, the temperture inside of your now-closed-garage will also increase for several hours, due to the above.

Should the SHUT-OFF valve become stuck closed for some reason, and pressure continued to build, the safety vent on the gas cap would open if a hose hadn't already split or popped off somewhere.

So my recommendation is to re-read my earlier posts, and pinch off that vent line. Remove the gas cap and start feeding pressure/smoke into the PURGE line. When you see/hear/smell the smoke coming out of the tank. Put the gas cap back on and let the system pressurize. THEN you can begin looking for smoke and leaks.

Good Luck!

Up North, they don't have this problem. Gasoline in the ground may be at 60°F...or colder. It may be that same temp outside. Say it's a high of 80°F, so the dT ~ 20°F max. In my example above, dT is more like 33°F and rapidly rising. This is why it's not a good idea to over fill any fuel tank.

[erikv11]

Ive got the nice turbo adjustment gauge which runs off tire pressure which would be perfect for this app. I keep promising it to Matt when Denver wins the SB.

Holy cow, have the chickens (or is it, to involve all of the farm animals, the Broncos?) now come home to roost???!!

Apologies, now back to our regularly scheduled programming ...

[abscate]

Ill cough it up after I get back from this trip...

[98v70dad]

My P0455 code eventually stopped. I'm not sure why. When the overnight temperatures got above about 50F it quit coming back. Also about that time I replaced the gas cap gasket and put the original OEM cap back on. The dealership sold me the cap from a much newer volvo because I wanted one with a lanyard and it worked (at least for 2 years). The new cap was more complicated and it had internal moving parts and springs, etc. So, I decided to go back to what' supposed to be on there. I dont know if the weather change or the cap change stopped the code from coming back, but its gone for now and July is when I have my emissions test so I'm good for another year. I replaced and/or inspected everything in the system (except the rollover valve). What a PAIN.

This has been a long thread. Thanks to everyone for the comments and help. We'll see if it comes back with the cold weather.

As promised here is my poem, Throwing Codes, which expresses my feels about P0455. I'm sure all of you can relate......

Throwing Codes

P0455, my most loyal friend
You never leave me
You're here to the end
I've known you for years now
Your loyalty shines
It takes a great effort to leave you behind
Some glorious day in the future, it seems
I'll change out a part
And you'll be in my dreams

98V70dad - 2015

[theWIFES_S70]

Throwing Codes

P0455, my most loyal friend
You never leave me
You're here to the end
I've known you for years now
Your loyalty shines
It takes a great effort to leave you behind
Some glorious day in the future, it seems
I'll change out a part
And you'll be in my dreams

98V70dad - 2015

Anyone know how to get this put on a sticker, like a high heat, long lasting timing belt sticker? I think we should all (well, those of us with the dreaded P0455) put this on our... carbon canisters?

Thank you for this. And congrats on your victory!