Can a bad VSS cause poor mileage ?

[California98Civic]

Sounds like it might be the evap system leaking little. It is for emissions. I'm not super experienced but I have spent probably scores of hours wort of time under my Civic and I have never yet smelled gasoline unless I was disconnecting fuel lines... so I don't think the gas smell you encountered today is normal. Suspect evaporative emissions system.

[user removed]

The charcoal cannister has a filter on the bottom. When the engine is running it purges the fuel vapors from the cannister. If the vehicle has been frequently over filled liquid fuel can get into the cannister. I let the pump click off once and quit filling the tank.

If a different fill procedure produced a change in the gas smell then try not filling completely and stopping sooner as you have done and see if the long tern results are positive.

The noise you heard is probably normal, vapors will fill the cannister and be absorbed into the charcoal, to be purged by engine vacuum when the engine is started the next time.

regards
mech

[Cd]

Thanks guys. Just to clear up something, the noise is coming from the gas tank itself.

Regarding the charcoal canister, there is no gasoline odor coming from it that i can detect.

It's been ages ago, but i asked you guys about the charcoal canister, and how often it need replacing. I think it was you Mech that replied that in years of mechanic work you only had to replace one or two, and that a faulty one is extremely rare.

Yet another puzzling thing is that I pass my emissions test ( due for another soon ) with no issues.

[California98Civic]

It does not have to be the canister itself. It could be the vacuum lines to the engine that flush the vapors once the engine starts. Engine vacuum draws out vapor. If the line has a leak, it will hiss for a while after you park, as air gets sucked into the line--seems to me.

EDIT: I wonder too if the hissing would be more common, longer, and louder when the tank is full as opposed to empty, because gasoline is "heavier" than air.

[Cd]

Here is a super quick 6 second video with the 'hiss' sound i was talking about.



http://s877.photobucket.com/user/mon.../hiss.mp4.html

I will check all of the lines again for any cracking.

[Cd]

What do you guys make of the exhaust smell i mentioned earlirer - just after i change my oil, the exhaust has a just a hint of that sweet smell of oil. It is similar to taking a whiff of an opened oil jug.

If oil is being burned into the exhaust, then i would have thought that it would show later in ways, such as my emissions test, a drop in the level over time on the dipstick, and a darkened color in the oil.
Instead, the oil has remained at the same level for a several months now ( nearly a year ), the color is a normal deep honey color, and i pass my emissions test fine.

[Cd]

I purchased a ( $ 17 generic ) VSS and will install it this weekend. Is there some test to check these things out with a voltmeter ?

I had a question about the oxygen sensor. I got a CEL signal that said that the oxygen sensor was bad.

If i drive the car and the CEL stays off for a good portion of the drive, does this mean that the oxygen sensor is working, but not functioning sporadically ?
I'll watch the CEL and see if it comes on again, and what it takes for it to go on ( like a fully warm engine )

1993 Civic DX automatic - around 125-130,000 miles.

[Cd]

bump

[Cd]

bum, ba bump, bump...BUMP.

Just to reiterate the question :I had a question about the oxygen sensor. I got a CEL signal that said that the oxygen sensor was bad.

If i drive the car and the CEL stays off for a good portion of the drive, does this mean that the oxygen sensor is working, but just functioning sporadically ?

Thanks !

[Cd]

Looking online, I get different answers regarding the Check Engine Light and how severe a problem it is when it come on then goes off again.

One of my codes was for the speed sensor, but what worries me is that there was another code for the oxygen sensor at the same time.

If I drive the car and the CEL does not come on, does this mean that the part is working ? ( electrical issue etc )

It's an emissions part, so i suspect the part will trigger a CEL when the engine is hot. I'll let you guys know. But if it does not, does this mean the part is good ?

The oxygen sensor part is a Bosch, with probably less than 10,000 miles on it. It's a real pain to take off too, so i'm hoping it's still good.