evap code/ hissing noise from intake

LukesCougar

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.

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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?

XR7-4.6 said:
... 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. ...
Click to expand...

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.
 
Yeah it's one of those things I can't really describe unless I'm right there, you just follow the path of the lines and replace each rubber junction as you go
 
Replacing just that one line did wonders, and I havent seen CEL since. Not sure if I've driven it enough to complete checking. But yea, still theres the burden of the other lines.

Time at the lift last week wasn't as productive as I'd hoped. It ended up as time being spent identifying the locations and whether or not I can fix them without lifting the car. I should have done some of that beforehand.

Starting from the front, looks like all of those can be done without lifting, until it gets to the charcoal can in the wheel well. Placing in/out that splash guard is challenging. I found the entombed can pictured below, but I was running out of time.

When I was looking at 96PRLBRD's article for the locations, I see that he took these components out before swapping out the lines, which makes sense. Theres no clearance, especially for the red indicated line. Do you guys also remove the plastic plate below the nose of the car? (Its the one that has a billion clips) It looks like if I dropped that too, I would actually be able to see how I can unmount the components. I see two connections (purple), but that can't be everything. I wonder if someone replaced the blue line already. Looks better, or a different material.

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Now, this has me thinking about the LSC because I have 1 evap code there, and every once and a while the car will smell like sulfur inside. Very different smell than what the bird was shooting out. Reading on other forums, people were speculating that it tends to be a line in the passenger side fender. If the charcoal can is there scrubbing the vapors, it might make sense that a leak up stream of the can would smell different

Does anyone remember where, or how many, hoses live in the direction from the can to the tank?
 
I was able to access all that with removing the wheel and plastic wheel well liner.
 
Ok. Did you go from the top of the bay down?
 
You work thru the wheel opening. There are 8 pieces about 2" long in the line, from the intake to the top of the gas tank. The piece between the solenoid and canister is different sizes on each end. I ended up with one short piece inside another to fit both ends.
 
I just replaced all the vac/emissions lines in my '97 Sport 4.6L, according to that long-standing PDF on TCCOA, plus a couple others I found.
Never had any codes prior to that or after...but prior to that, she developed a slight tremor while in gear that I can't track down...so went for the hoses first to eliminate possible vac leaks.

I had to remove the front fascia/clip to get in there to replace the hoses connected to the evap components. I tried for an hour or two to get in there through the wheel well after removing the wheel & fender liner only, but could only manage to get one arm in there, which was useless (I'm tall & broad, so tight spaces don't work with me). Once I removed the front clip, the evap components were totally exposed and became very easy to access & replace those hoses.

Below are 'before & during' photos...but I dumbass'd and forgot to take 'after' photos.

NOTE: One of the 2" hoses from the canister to the solenoid is two different sizes on both ends: One end is 5/16" (or 1/4") and the other end is 3/8". Good luck finding that part, but you can buy a little Dorman kit of various hose connectors for a few bucks that will work to splice those different size lines together.

In the end, my Bird's tremor still exists...don't know why, so I'll be posting for advice on that shortly.

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Last edited:
Which one had the atypical size? Was it this one, centered in picture?

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