Testing Evap Canister and Pump

[AndyA]

I am getting evap DTCs so I am checking the system as well as fixing the gas tank burping problem as the check valve is now stuck closed.

The canister doesn't feel like it has gasoline in it and isn't leaking charcoal. How do I test the pump and make sure the vent is functional?

It seems our vehicles don't have a vent valve solenoid to test so it is always open to atmosphere?

Do I need to disassemble part of this and clean it?

Thanks, Andy

 

[macleanflood]

Smoke testing the system will show you if has any leaks.

Alternatively you could plug hoses and see if it holds vacuum...but if it doesn't then you don't know where the leak is...

-Mac

 

[AndyA]

Thanks. I am thinking that air cannot get out of the tank during filling. How can I confirm that the vent after the charcoal canister is not blocked? Is it possible to disassemble it?

Andy

 

[macleanflood]

Thanks. I am thinking that air cannot get out of the tank during filling. How can I confirm that the vent after the charcoal canister is not blocked? Is it possible to disassemble it?

Andy

Could be as simple as hooking up a blow gun to the evap line and pushing compressed air into the tank.

If there is a blockage it might blow it into the tank. If not you'll hear it coming through at the fill neck.

Fysa areated gas is highly explosive.

-Mac

 

[AndyA]

Well that sounds a bit...scary. I wish DC would have put how to test everything in the FSM like Ford does. I've reinstalled it for now to see how it goes. Andy

 

[Rickyd]

Well that sounds a bit...scary. I wish DC would have put how to test everything in the FSM like Ford does. I've reinstalled it for now to see how it goes. Andy

Yeah the ford evtm's are really nice. Pinouts for every connector,connector locations.nice pictures.

Chrysler doesn't even know how some of their circuits are wired...

What codes? A smoke machine would be a good start if it is a leak. After trying a known good gas cap.

 

[AndyA]

Yes, I am going to try the smoke machine, but I had the hard start after filling up today. For $40 I'm just going to throw a new purge valve on there even though it appeared to be working when I tested it a couple of days ago.

However my understanding is a smoke test won't show issues with the evap canister, pump or any of that gubbins because there is a valve in the tank that closes off access to the evap canister except when refuelling or the PCM is leak testing. So I guess that part has to be smoke tested separately.

Andy

 

[Rickyd]

Yes, I am going to try the smoke machine, but I had the hard start after filling up today. For $40 I'm just going to throw a new purge valve on there even though it appeared to be working when I tested it a couple of days ago.

However my understanding is a smoke test won't show issues with the evap canister, pump or any of that gubbins because there is a valve in the tank that closes off access to the evap canister except when refuelling or the PCM is leak testing. So I guess that part has to be smoke tested separately.

Andy

That is why i asked what codes it has? Is it saying a leak? Or that it won't try to test?

 

[AndyA]

P0440 Evaporative Emission System
P0441 Incorrect Purge Flow

My understaning of P0441 is that the tank is failing to hold pressure long enough during the test.

Andy

 

[Rickyd]

The hoses and fittings on the top of the tank like to crack. Hopefully that isn't where it is.

 

[AndyA]

The hoses and fittings on the top of the tank like to crack. Hopefully that isn't where it is.

Thanks. They looked OK to me but if the system can reliably detect a 0.5mm hole then my eyes are not that good! Andy