Emissions leak/gas cap issue

[Randy Hinebaugh 2]

I've been battling this over the last several years, hopefully someone here will have a solution for me. A few years ago I started getting the small code emissions leak warning light. I got it scanned at Autozone, they told me what it was, and told me to check the gas cap. Did this several times, each time it was reset the light would stay off for weeks at a time before it would come on again. That series of fault codes has different values depending on the size of the perceived leak. the codes kept progressing in leak size until eventually the 'Check Fuel Cap' warning came on. So I buy a new cap from Autozone and put on, same thing. I've read on here since then that the Autozone design is different than stock and doesen't work. So, now I've bought a Motorcraft replacement and put on. I've wiped off the sealing surface where the cap goes on and installed the new cap. Unplugged the battery to reset the computer, and drove it daily for two weeks with three or four starts per day without the light or warning coming on, then all of the sudden the warning pops up. I'm at a loss now, seems like if it was really a leak it would come up much sooner than that, like after three or four startups. Any ideas?



I should probably add that the problem started shortly after changing the rear shocks, I had to take the 'shelf' over the spare loose that has some emissions canisters on it. I've zip tied all the barbed fittings, and applied a light coat of grease to the push in fittings to make sure everything is sealed up.

 

[Mark Keefer]

Check the evap system above the spare tire. If u got a hose off it will trip the engine light next if left go

 

[EddieS'04]

Time to take it to a shop that can run a smoke test. So the leak can be found.

IMO, that will be better than chasing your tail, and parts swaping

 

[Bob Floyd]

The evap self test takes a long time and several different drive cycles to run, hi way, Idles and city driving and the vehicle needs to be fully warmed up so that explains why it takes so long to pop up also it needs to fail more then once to set the light. My guess is when you change the shocks you created a leak in the evap canisters or a hose from the engine back to the evapcanisters. Make sure everything is connected all hoses and the electical connections at the cansister vent. If the vent valve is stuck it will never quit showing the code. When the test runs it closes the canister vent and opens the canister purge to create a vacumme on the fuel tank and canister. If it wont hold or get up to the set ammount of vacumme it will set a code. Hope this helps

 

[POJ Irving]

Randy H, If you can smell petrol / gas fumes at some point whether while driving or not, but while the engine is running it might be the Evap canister purge valve. The hole may be very small, the size of a pin head. Check the entire connection, take off the Evap canister purge valve and the pipe that leads from the fuel tank in order to find it. Part # 9G271 AA which incidentally is no longer available from Ford as this part is now obsolete according to local dealer. This hose should not be examined unless you have disconnected it from the two sources after you have disconnected the battery of course. Feeling it or looking at it with light will not help in its present location. This was my cause for the code.



Anyway, since Ford no longer supplies this part I had to be inventive so this is where Goop sealant and adhesive came into play along with black electrical tape. I believe the photo my still be in my library. It starts with the hose with the green cap.