CEL - Fuel Evap
 

Over the past several months I have noticed a pretty good whistling noise. I have done some searching and found that many people have the same issue and it was coming form the fuel door area.

About 2 months ago my CEL come on. The car didn't change at all how it ran or performed.

Today I was at Advance Auto and remembered that they do free diagnostics. The guy said that there was an error coming up that said something like Fuel Evaporater Circuit.

Any suggestions? I would like to fix myself.

1998 Base 90,xxx miles

Without the actual code(s), any suggestions would be a guess.............

I know, but I am trying to avoid the $100 fee for the shop to do a 2 minute task.

Go find another AZ or national parts store and have them give you the actual code #s (for free as they do). Don't settle for the generic overall code or what they say they think the code means - get the actual P-number(s).

For instance, I had an issue not along ago on another car and the AZ guy just kept trying to tell me I had "multiple cylinder mis-fire" with his explanation "due to cheap gas 'round here". You'll be fine w/ a reset and a bottle of fuel system cleaner". I told him I'd be happy to buy a bottle of Techron even though I'm sure it's not the issue but I want the actual codes not the generic 'multiple cylinder mis-fire' code. See, I was 3/4 thru a tank a gas that day so I was certain in wasn't a 'bad gas' issue or it would have popped up way sooner. Plus a cylinder misfire isn't something you want to just hope it to goes away... especially w/o knowing the real cause.

Finally he gave them to me and as suspected, had nothing to do w/ cheap gas... Without them, I would have gone after a completely different issue looking at all 8 cylinders, the fule system or ? and possibly had the car towed. Instead, I now knew it was only 2 cylinders. So, w/ a better focus point, I started at the coil packs for those two cylinders which looked fine and no leaks. Then followed the hose for that bank and bingo, found it had come loose near the intake. I still bought the Techron b/c I needed it for another car.

As said, it's the only way to start looking in the right direction or you'll get as many guesses as there are posters in your thread.

Good luck :)

These are the likely candidates:

P0440 Fuel Tank Ventilation System - Above Limit
P0441 Fuel Tank Ventilation System - Above Limit
P0442 Fuel Tank Ventilation System (Micro-leak) - Below Lower Limit
P0444 EVAP Canister Purge Valve - Open Circuit
P0445 EVAP Canister Purge Valve - Short to B+/Short to Ground
P0446 EVAP Canister Shutoff Valve (Function) - Below Lower Limit
P0447 EVAP Canister Shutoff Valve (Output Stage) - Open Circuit
P0448 EVAP Canister Shutoff Valve (Output Stage) - Short to B+/Short to Ground
P0450 Tank Pressure Sensor - Signal Implausible
P0452 Tank Pressure Sensor - Short to Ground
P0453 Tank Pressure Sensor - Short to B+
P0455 Fuel Tank Ventilation System (Major Leak) - Below Lower Limit

Really need to know exactly which code you're getting. Might be worth investing in an affordable code reader.

Well, this has been a long time. After that trip I ended up replacing the gas cap with an autozone model. That seemed to do the trick, for a while.

It seems that the cel comes back every once and a while.

The code is P0455.

Should I try a OEM cap? I never hear the rush of air when I take the cap off.

Get an OEM cap, they are the only ones that do not seem to cause the car to throw codes........

Hi , so i keep getting the p0455 code and i replaced the gas cap with the orginial one and still coming back. Any help??

You are going to need to start checking both the fuel system and the EVAP system for leaks. As it is a large leak, you may be able to hear it.

I can only hear it at random times when im driving , i was thinking fuel vent valve because its hard to fill her up now when she gets above half tank it goes slow , so what happens if i ignore this problem? Just low gas milage?

Well, for one, the car won't pass emissions inspection.

Just went through the evap. issue. Mine would get a vary rare 0442. I thought gas cap and I keep clearing. Then at inspection it showed that the evap monitor was not completing and therefore 30 days to fix. I broke for the first time and went to an indie for help. Mine was a canister and purge valves. This is a hard one to diagnose and hard to get at and that's why I figured it would be less stressful to have a pro do it

How do i find this leak ?

So i know its my chacoal canister vapor canister that has leak. Any info about this like how bad is it and i havent got it fixed sonce it started for about 5 months no problem other than gas goes quicker, and thinking about fixing it myself , or would you recommend a professional on this part. Thanks