2004 GT EVAP Questions

[SSgt Dan]

I recently bought a 2004 Mustang GT, which has thus far been an amazing machine, minus one small annoyance. When I bought it, it had a CE light with a fault code of P0442 (Evaporative Emission Control System Leak Detected (small leak)), and me, being the genius that I am (not), decided to not bother with having the seller fix it before I bought the vehicle, thinking its probably just the gas cap or something silly like that. Unfortunately that's not the case, seeing as how I've changed the cap twice now and the code still pops up. I've visually checked all the lines in the system, and as far as I can tell are in good shape. I also haven't seen or smelled any raw fuel anywhere around said lines. So long story short, my questions are: What component is most likely causing this fault code to trip? And MUCH more importantly (lol), where are the main EVAP components located? (I have a Haynes Repair Manual, but the pictures and location descriptions in that book are almost impossible for a budding car enthusiast like me to figure out )

Some other small tidbits of information. I am experiencing absolutely no drivability issues, the fault code tripping interval seems to be slightly erratic (averaging about once a week), and from what I've noticed, the code doesn't seem to be dependent on how much gas is in the tank. However I haven't been able to get more than one fill-up in before the fault code trips. Not sure if it's just coincidence.

Any and all help/suggestions/advice would be GREATLY appreciated!

Dan

[OsirisGuy]

I would also like to know about this (the EVAP system). I posted up just the other day how I was getting the same code and have even seen P0456.

I could probably check on a few things first, but haven't gotten the chance yet. If anyone here knows first hand that would be great.

Saw this on the bottom of the page:
Evap leak Small

[CopNaStang]

I have heard on the Mustang about a EGR downtube that cracks. Maybe one of the guys on here can answer that one. I know on the Vics it was always the purge valve or the charcoal canister, located in the black box in front of the rear bumper. I had to replace both in my vic due to fill up issues. The gas pump would shut off as you would try to fill it. It got so bad I couldnt get much gas in it.

[Scut95]

If the fuel cap is good, it could be the filler neck. Unfortunately the evap codes are a nightmare to diagnose even for experienced techs. I don't have my service manual handy so unfortunately I can't help with the canister location. It might be up in one of the front fenders but don't hold me to that. When you do find it, inspect all the hoses and the canister itself. If it was the canister I would assume you would be having driveability issues though. It sounds more like a fuel filler neck or a pin hole in one of the lines.

[OsirisGuy]

After going through OPLIN and Haynes I am not much further in solving the problem, I basically have to check everything it seems. Both the canister and the purge valve should be in the engine bay. Haynes points the purge valve on the passenger side near the firewall or just above and off of the valve cover (it looks like). However a lot of the info for the SN95 in Haynes only applies to the first couple of years i.e. the photo for the 4.6 engine shows a Cobra plenum for what looks like the '95 Cobra.

[CopNaStang]

I looked under my hood and dont see it. Its hard to see under my car right now, but looking and the EVAP sticker under my hood, and from what I looked at under the car, I believe on the new cars they are in the rear. It shows it near the passenger side. I thought I saw what looked like it on the drivers side rear near the back of the drivers side wheel well. On the EVAP chart, I would also look on the passenger side of the car, straight across from the gas tank (Maybe in front of the rear tire). I would call Ford and verify location and then it should be easy to spot. In the Vic, it was a plastic looking square box. The purge valve was located right by it, connected to one of the lines. All the new cars I have worked on, including my nieces Blazer, its in the rear of the vehicle.

[OsirisGuy]

I confirmed the location for the valve which is on the passenger side just above the valve cover towards the firewall. See included attachment. I can't tell where the canister is though.

However I now have another very suspect-able cause. I just stopped to get gas tonight and looked under my car and saw a very unpleasing site, I was leaking some fuel.

It looked like it was leaking from the bottom of the filler tube near the tank itself and ran down the bottom of the fuel tank. However the drip was only prominent when I was actually filling the car and not when it was sitting itself. This could mean it ran down the filler tube as well.

But at 11:30 at night, with an 8:30am class and plenty of work to do for the week finding this pinhole wasn't my immediate concern. I'll be home tomorrow afternoon when I can look at it.

Also using the (trip meter/gallons of fuel) fuel economy method I showed a MPG of over 22MPG with a 60/40 HWY/City driving! Pretty impressive.

So now the current big fixes are this and a horrible squeak coming from the driver wheel well, which might be related to the steering. (Which is another common problem for Mustangs).

My friend's girlfriend's sister drove a New Edge V6 and she had a similar fuel leak problem FWIW..

[CopNaStang]

I wonder if the vent valve(not sure if that is the proper name) and canister are in back though? The purge is under the hood, sorry I get the two confused. I ordered all 3 from rockauto and replaced them. I did the purge first and it didnt fix it, but after replacing the rear vent valve and canister it was perfect.

[Scut95]

There is a gasket between the filler neck and the tank and it goes bad on mustangs all the time. My dad's 2000 gt had it leak and my 95 went bad too. I don't remember if he had a CEL light though. The creeking noise is most likely the rack. It's easy to replace and it's not that expensive. Ford doesn't make the rack anymore so you will have to get a reman (i recommend Napa) and they will want the old one back as a core.

[OsirisGuy]

I figured it had to be a gasket and the ethanol eating away at it.

I'm really hoping it's not the steering rack but rather just some bushings or it just needs a good greasing and I know the Mustang rack tends to make that noise for one reason or another.

[CopNaStang]

Good info about the gasket on Mustang filler necks. Never heard that before.

[CrzyBeautiful]

Quote: Originally Posted by OsirisGuy I confirmed the location for the valve which is on the passenger side just above the valve cover towards the firewall. See included attachment. I can't tell where the canister is though. However I now have another very suspect-able cause. I just stopped to get gas tonight and looked under my car and saw a very unpleasing site, I was leaking some fuel. It looked like it was leaking from the bottom of the filler tube near the tank itself and ran down the bottom of the fuel tank. However the drip was only prominent when I was actually filling the car and not when it was sitting itself. This could mean it ran down the filler tube as well. So now the current big fixes are this and a horrible squeak coming from the driver wheel well, which might be related to the steering. (Which is another common problem for Mustangs).

Our our cars siblings? Because my car is doing the EXACT same thing! Including the squeak from the driver's side wheel!

I had the CEL checked out and was given the following codes:

P0442
P0445
P0457

I did have a quick question for those of you who have an 99-04 Mustang. Did these cars originally have a locking cap? My cap locks & I have been reading around that the locking cap can cause these codes to go off.

Before the CEL light came on I would randomly get the "Check Fuel Cap" light. I would make sure it was on tight get back in the car & after a few drive cycles it went off. But the other day, after pumping gas I noticed that there was fuel leaking from the bottom of the car - but *someone* told me that it was just the overflow... After a few drives not only was the "Check Fuel Cap" back on but now the CEL light...

At times I have smelled fuel in the cabin - so I definately think that this is a leaking hose issue & not just the gas cap...

How much should I expect to pay for the hoses to be replaced?

[OsirisGuy]

Quote: Originally Posted by CrzyBeautiful Our our cars siblings? Because my car is doing the EXACT same thing! Including the squeak from the driver's side wheel! I had the CEL checked out and was given the following codes: P0442 P0445 P0457 I did have a quick question for those of you who have an 99-04 Mustang. Did these cars originally have a locking cap? My cap locks & I have been reading around that the locking cap can cause these codes to go off. Before the CEL light came on I would randomly get the "Check Fuel Cap" light. I would make sure it was on tight get back in the car & after a few drive cycles it went off. But the other day, after pumping gas I noticed that there was fuel leaking from the bottom of the car - but *someone* told me that it was just the overflow... After a few drives not only was the "Check Fuel Cap" back on but now the CEL light... At times I have smelled fuel in the cabin - so I definately think that this is a leaking hose issue & not just the gas cap... How much should I expect to pay for the hoses to be replaced?

I'm convinced that Mustangs come off the assembly line with a driver side squeak. I took a bottle of WD-40 and tried to get into every bushing and pivot, just to see if it would curb the squeal, which it did not. I knew it wasn't my power steering since the car wasn't running and when I turned the wheel it still squealed. Although I should probably still check the power steering fluid to be sure.

Anyway I was able to locate where the sound was coming from and it sounded like the steering knuckle right behind the disc brake. Unfortunately my lug nut key seems to be stripped in one direction so I could not take off my rims and find the exact spot.

Good news is that I think I narrowed down where along the fuel line I am leaking. Right where the fill tube and the tank connect. Bad news is now I will have to drop the exhaust, and I don't know what else.

As per your problems CB, what kind of locking cap do you have? Is it just the general twist until it clicks which is from the factory? Or do you have one that locks with the key? I do not know if the key version came from the factory, however if that's what you have and it's a third party manufacturer or perhaps even a different model year it would explain a lot for the "gas cap" light.

As for the codes - P0442 is a small leak detected, P0445 is the PCV has a short circuit somewhere. P0457 is a loose/off gas cap. I'd say you have two problems and one is being caused by your gas cap. A new one should get rid of the gas cap light as well as the P0457. Hopefully it will clear the P0442. P0445 you will have to check, it's possible a ground is loose or the PCV is just malfunctioning. Could of even had a squirrel nibble on the wire. Hopefully this is the other cause for the P0442 code (and probably more likely). Getting rid of that electrical short should clear the P0445 code too.

I doubt the overflow over flows onto the ground. Like I said before, I think that the ethanol eats away at the fuel line and especially the gaskets.

I don't know how much the new fuel lines will cost, probably shouldn't be too much just make sure they are rated for fuel. I wouldn't know the price from a shop. Then again I haven't priced fuel lines so it could be more than I'm thinking.

[CrzyBeautiful]

Quote: Originally Posted by OsirisGuy As for the codes - P0442 is a small leak detected, P0445 is the PCV has a short circuit somewhere. P0457 is a loose/off gas cap. I'd say you have two problems and one is being caused by your gas cap. A new one should get rid of the gas cap light as well as the P0457. Hopefully it will clear the P0442. P0445 you will have to check, it's possible a ground is loose or the PCV is just malfunctioning. Could of even had a squirrel nibble on the wire. Hopefully this is the other cause for the P0442 code (and probably more likely). Getting rid of that electrical short should clear the P0445 code too. I doubt the overflow over flows onto the ground. Like I said before, I think that the ethanol eats away at the fuel line and especially the gaskets.

I think you may be right. I looked under the car today and the coils around the fuel lines were wet - not to mention that the gas mileage I have been getting recently is HORRIBLE. I take it into the shop tomorrow so hopefully I will have some answers by Thursday - I will def come back & post my findings - hopefully they will be able to tell me something that I can pass along. From the searches I have done - it looks like this is a very common issues with not alot of feedback to go off of....

[OsirisGuy]

If your gas mileage is that bad perhaps you have a bigger leak than expected, either through the gasket, through the PCV system, or just another leak somewhere, or a combination of.

Of course I am only saying this because my gas mileage hasn't been affected, so I can't vouch for the decrease in MPGs

[CrzyBeautiful]

*Update*

Dropped SwtChryPi off at the mechanic. He hasn't called yet, but when he does I will post results here. I am also having him look into the squeak coming from the wheel well...

[CrzyBeautiful]

*Update*

Cleaned the O2 Sensor, HVAC was re-wired & seals replaced. The hoses were fine.

As for my Wheels, well there was a little bit more fixin' for them:

Rotors Resurfaced
Spring Adjustment
Master Cylinder Replacement
Brakes

Alot of the above issues stemed from one problem which of course caused a chain reaction. So today's lesson kids is get *it* fixed as soon as you possibly can.
I also went ahead and ordered my wheels today from american muscle...