2005 Expedition P1450 EVAP leak

[71hotrodpinto]

Hey there, I know this is an old topic, however I am still fighting this issue with my 2005 Expedition since about June 2022. I'm Still getting a p1450 Evap leak/plugged with a strong gas smell when I start it up and for a while after it warms up.
Replaced the entire EVAP canister assembly that sits above the spare tire. Brand New Ford unit from the dealer
Replaced the gas cap of course, new Motorcraft unit.
Replaced the EVAP Purge Valve on the firewall. New Motorcraft
Replaced the Hose that goes to the Intake manifold from the EVAP valve. New Ford unit (Old one was like a sponge)
I've replaced my gas tank with a unit that didn't have cracked fittings on it. Good Used.

Of note: there is, and always has been, a hose that runs up along the Fuel filler tube to the top by the gas cap that doesn't connect to anything yet comes from the EVAP assembly. very weird. The truck passed smog with no issues when I got it in Nov 2021.

I bought a cheaper smoke machine on amazon, but haven't used it yet, I have a brand-new pressure transducer with lines that I'm about to install. But I figured I'd try the smoke machine first pumping through the gas cap adapter I bought. Did anyone ever try that? if so, what were your leak down results?
I'm a very meticulous person and usually fix more things than is "needed" but everything I've touched hasn't changed anything.
Anyone ever find an elusive leak?
Thanks in advance!

 

[S20Workstation4]

My 2010 Expedition had the CEL Lit for a EVAP Leak for about 9 years
I had the same problem: strong gas smell, especially on first startup. I never did a smoke test on it, but I kept also getting a "Check Fuel Fill Inlet Message".

I figured out that because It has the "Capless Fuel System", the little flap inside was actually not engaging with the 2 clips on the side. I could press on the flap and open it, without pressing the 2 clips on the side like the gas nozzle would do for you at the pump. It was allowing a leak through there, enough to trigger a code.
I ended up pushing the flap all the way in, and then releasing it fast so that it would engage quickly with the 2 Clips.

It seemed to have worked, the Code eventually went away. It still comes up as "Pending" every once and a while, but the computer clears it before it even can throw a CEL.

You said that you replaced the gas cap; do you have the "Capless Fuel System"?. If you do, this could be your problem...

 

[71hotrodpinto]

No , thank you for the reply, but it’s the older capped style

 

[MesaGuy]

Assuming that replacing the Evap Purge Valve doesn't/Didn't help and/or the canister. You need to check all of the interconnection hoses between the canister, the purge control valve, and the gas tank. 1450 usually means "too much" vacuum, meaning the vacuum is not bleeding off fast enough. That usually happens because it cannot bleed to the canister because the canister is flooded with fuel (or clogged, or shot), the evap purge valve is not opening at all (stuck/failed) so no over-vacuum bleeding at all through that bleed valve, or one of the hoses or tubes is clogged. For the hoses/tubes, what usually happens is part of one of the rubber hoses crumbles inside, and jams up the rubber hose with a crumbled rubber bit (just replace the hose, detect by blowing through it, or use a vacuum guage). Or (worse), a rubber crumble bit has broken off, but then moved into a metal line. Detected the same way, blow through it, or use a vacuum gauage. To fix on the metal line, on metal line disconnect hoses from both ends, and try using compressed air to blow the blockage out.

You typically get a different code for a lose gas cap or (on new models) gas "flap" that is not sealing correctly.

 

[MesaGuy]

Much less often.... Wiring problem is preventing the purge valve from being powered. (When it happens, 80% of the time its a bad ground, find the nearest ground straps, pull the bolt sand, remount bolt/strap, repeat. The other 20% of the time, the wire between the ECM and purge valve has a problem. You can buy on eBay an ECM breakout box, and check the line from ECM to the purge valve, but that is a major hassle. Last possibility is that the ECM itself is having a problem (rare, but occasionally does happen on older vehicles.)

Most common: Canister, Purge Valve, Hose-clog, Hard-Line Clog>
Ground, Purge Control Activation Power, Purge Control Activation Control.
ECM-side sensor input, or purge vavle control outputs troubled (bad ECM).

In that order.

 

[71hotrodpinto]

Well you did touch on one thing , and that’s rubber crumbling and clogging up the lines. There was the one line I replaced coming off the intake that was collapsing and falling apart. If I’m lucky it is in the valve on the firewall. Although I already replaced that valve, maybe it’s got crap in it now. Will check. I hope it didn’t go to the assembly at the back , that was a pain to remove and replace!
With that I may just blow out all the hoses/lines just to be sure!
Great thoughts and help thank you !