evap code/ hissing noise from intake

LukesCougar

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Olney Illinois
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1996 Cougar 4.6L v8
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Alright so ive replaced just about every vaccume line in the engine bay/ under airbox, and charcoal canister and the 2 valves wired up beside it. Still getting an evap code (i have yet to drop gas tank and check back there)

Also as of recently the intake noise has gotten loud. Almost like the motor has too much vaccume (originally thought it was a bad vac line hissing but the noise comes from throttlebody/intake manifold.

Im guessing the only thing left for the code would be to replace the vent and vac lines at gas tank? or feul cap? Also would the air intake noise be related to an issue with evap?

Really confused i thought replacing canister/ purge valved and vac tubes up front would get rid of it.
 
You can hear the air going across the throttle blade. Especially if you have removed the intake silencer. That's why I mentioned the cigar trick; find if there are any leaks.
 
I wouldn't jump to the tank lines so fast. "just about every" vacuum line in the engine bay? Since the vacuum noise is coming from the engine have you tried spraying water or carb cleaner in various locations around the intake to try to pinpoint the source of the noise? My guess is most likely your EVAP code comes either from the purge solenoid or the canister. Could it be that the vacuum lines to the purge solenoid got reversed to cause the EVAP code?
 
If you are hearing hissing at the throttle body or manifold, then your leak is up there somewhere that you have not found. Post pictures of what you have already replaced.
 
If Im derailing this thread, feel free to move to a new thread.

I had driven about 20 miles, and when I parked I noticed a hissing before I shut the car off. The area immediately smells like sour gas vapors. The second time I looked under the hood, the problem appears obvious (no snakes). The rubber sleeving is beginning to fail. Luckily, this one is easily accessible.

fuelline_040224.png

Matt had explained to me that I should use straight fuel vapor hoses to replace it, but implied that the rest are bound to fail just as well. So theres other connections along the way to the tank.

How many of these are connections will require tear down of other parts?
Is the diameter of the hose important, or is it industry standard?
I vaguely someone suggesting to use a silicon spray on the connections, is that something you're familiar with?

Thanks for reading

Edit: (This is the tbird)
 
It’s 1/4” (ID) fuel and emissions hose, you can get lengths or even rolls from the parts store, but you’ll only need at most two feet worth in total. The hardest ones to get to are around the canister/purge valve up front, there are a few short sections in succession, remove the tire and splash guard to gain access to get to those, the rest you can easily follow back along the fuel lines under the car, replace each until they neck up to the tank.

The tank one won’t be accessible without dropping it so I’d just leave it until you needed to replace the pump someday. That one tends to be ok most of the time at least since it’s relatively shielded from the elements compared to the rest directly underneath or in the engine compartment
 
Thank you Matt, appreciate that. Took PTO and booked a lift. Time for an oil change anyway. I'm reading more about it, and I see discussion about the hidden connection behind the inner fender of passenger side wheel well. Is that the one you're talking about below? Is removal an obvious nut/bolt connection?

... The hardest ones to get to are around the canister/purge valve up front, there are a few short sections in succession, remove the tire and splash guard to gain access to get to those, the rest you can easily follow back along the fuel lines under the car, replace each until they neck up to the tank. ...

When I first read Splash Guard, I pictured that plate under the bay that nearly fell off the car way back when I got it. I kept it at my fathers place, I have no idea where it is now heh
 
When you remove the wheel well splash guard the connections are pretty obvious. Follow the hard lines and replace every rubber hose you come across.
They’ll probably fall apart as you disconnect, I’d suggest wearing gloves disintegrating rubber is nasty.
 

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