Another mechanic question.

[Goldeneagle]

2002 Cadillac Escalde. The fuel tank is building up pressure like it is not venting. Enough pressure to affect the float for the gas gauge. We've replaced the fuel cap, vent valve and purge valve. These have not fixed it. Any idea's?

[toastie]

replace EVAP canister? Is it giving any engine error codes?

[easeup]

we don't know all of the symptoms, so I can only suggest you try a youtube search for Cadillac fuel tank pressure.....there is lots of stuff out there

[Goldeneagle]

replace EVAP canister? Is it giving any engine error codes?

It is throwing a code. I'll get it again today. I forget what it is.

we don't know all of the symptoms, so I can only suggest you try a youtube search for Cadillac fuel tank pressure.....there is lots of stuff out there

It's building up enough pressure to affect the float for the fuel gauge. When you take the gas cap off, it releases a pretty large amount of pressure. Way more than it should. Also throwing a code.

[Goldeneagle]

The code is P0446

[TexasBob]

Code isn’t overly helpful, they usually aren’t. Looked at a evap system diagram online- you should search one for the exact year. Looks like you’ve replaced most key parts. Down to an issue in the rollover valve on top of the tank (makes sense if it failed closed), or one of the lines.

[easeup]

there is nothing left to replace other than the fuel tank pressure sensor. It serves to tell the ECM to open or close the tank vent valve or the purge valve. So without going into a lot of trouble shooting methods you could do that one too.
If that dont clear it out, it would seem there is a electrical wire problem and the hunt begins.

https://themotorguy.com/fuel-tank-pressure-sensor-function-location-and-faqs/

[HTDUCK]

It's a restriction in the vent line not allowing vapor to flow through system or a faulty tank pressure sensor
Take the line off and blow compressed air through it.
Also check the charcoal cannister itself, it may be coming apart internally.

[Goldeneagle]

We pulled the battery cable just for grins to see if maybe it needed to reset after changing the parts. So far it's doing OK except for one thing. It ran out of gas while showing 1/4 of a tank on the gauge. Looks like we'll be dropping the tank to replace the float. Will do the pressure sensor while we're at it just because. These older newer vehicles drive me nuts. I liked it better back when the didn't have all this crap on them.

[Big Lee]

The evap canister and and the vent filter need to be replaced. They ingest dirt and stop up. Likely the new vent valve you installed is already impacted from the dirt and debris and will need to be replaced at the same time. The new evap vent filter will need to be relocated up higher and out of reach of road debris/grime.


Edit..... General Motors World Class Tech. And 25 plus yrs experience on the service side of the industry. With all that and like $10 you can buy a cup of "cheap" cawfee at McDs 😆

[Goldeneagle]

The evap canister and and the vent filter need to be replaced. They ingest dirt and stop up. Likely the new vent valve you installed is already impacted from the dirt and debris and will need to be replaced at the same time. The new evap vent filter will need to be relocated up higher and out of reach of road debris/grime.


Edit..... General Motors World Class Tech. And 25 plus yrs experience on the service side of the industry. With all that and like $10 you can buy a cup of "cheap" cawfee at McDs 😆

Where is the filter located?

[Bill]

FYI, throwing a P0446 code can mean the gas cap was not fully turned closed after refueling- it’s happened to me several times. It’s not your problem- but I mention it for others reading this.

Otherwise- good luck!

[Big Lee]

Where is the filter located?

It attaches near the vent solenoid under the truck. The relocation requires about 6 ft of heater hose and new filter.

You'll need a vent solenoid. Evap canister. Blow out all the lines attaching.

[Goldeneagle]

It attaches near the vent solenoid under the truck. The relocation requires about 6 ft of heater hose and new filter.

You'll need a vent solenoid. Evap canister. Blow out all the lines attaching.

Thanks Lee.