Shell-Nitrogen Enriched Chevron-Techron for GZ250?

[Easy Rider]

Originally Posted by alantf

?????????????? Is this something specific to American/Canadian vehicles? I've driven English/European vehicles, & NEVER seen a "check engine light".

Probably not but they may call it something different on your side of the "pond".

It is there mainly to tell you when the emission control systems are not working right......and loss of the proper presssure in the gas tank is but one of the things it monitors.

[Water Warrior 2]

Originally Posted by alantf

?????????????? Is this something specific to American/Canadian vehicles? I've driven English/European vehicles, & NEVER seen a "check engine light". I've also never seen a detector on the filler cap, to tell me if it's been replaced properly. :??:

I will hazard a guess and suggest it might have something to do with the charcoal cannister and the need for vacumn for proper operation. Loose cap and no vacumn.

[Easy Rider]

Originally Posted by Water Warrior

I will hazard a guess and suggest it might have something to do with the charcoal cannister and the need for vacumn for proper operation. Loose cap and no vacumn.

Vacume is just another kind of pressure.......isn't it ?? :biggrin:

I think you're probably right.

[Water Warrior 2]

[quote=Easy Rider]

Originally Posted by "Water Warrior":1ro439nn

I will hazard a guess and suggest it might have something to do with the charcoal cannister and the need for vacumn for proper operation. Loose cap and no vacumn.

Vacume is just another kind of pressure.......isn't it ?? :biggrin:

I think you're probably right.[/quote:1ro439nn]

A negative pressure or absence of pressure..........take your pick.

[alantf]

On my dashboard there's a little picture of an engine, that lights up when you switch the ignition on, then goes out when the engine's running. We call it the "engine management system", & it comes back on if the engine's not running right (although it doesn't monitor pressure in the fuel tank). It monitors things like timing,fuel, catalyst etc. Is this the same thing you're talking about?

[mrlmd1]

Yes, that's it. And I don't know about over there, but over here it does monitor fuel tank pressure, for many, many years now. That will try and prevent atmospheric leaks from gasoline fumes, prevent spills from a rollover, etc, if the gas cap is not properly attached or is missing. That's probably one of the first things you check if the light's on.

[Easy Rider]

Originally Posted by mrlmd1

if the gas cap is not properly attached or is missing. That's probably one of the first things you check if the light's on.

Apparently leaving the cap off doesn't trigger it right away. I drove a mile home from the gas station yesterday and it didn't come on..... :roll:

[mrlmd1]

It doesn't reset right away either. You might have to disconnect the battery for a few min. if it doesn't go off in a few days.
And if it's on it can be many other problems, vacuum/air leak. faulty sensor (unlikely). and many cars have more than one sensor which can trigger the check engine light to go on. You have to read the codes with a diagnostic meter. I'm having this problem now and the car runs absolutely fine.

[alantf]

A couple of years ago I was about 30 miles from home, when the light suddenly came on, & the car started to run really rough. A friend with a good bit of engine knowledge, who was in the car with me, suggested parking up for half an hour, but this did no good, so I carried on home at under 30 mph and the car got us there, although it was still running very rough. The following morning I got up to take it to the mechanic, & it ran perfectly (& the light was out). Never had a problem with it since, so I still don't know what caused it.

[93CutlassSupreme]

Missing gas caps cause SES warnings when the EVAP system detects atmospheric pressure in the system.


This will only become more common as the EPA toughens emissions standards and EVAP systems become more advanced. Some good has come from this (returnless fuel systems for example) but as ever the cost of new cars increases due to more and more advanced emissions controls.