Black Smoke and runs rough after refuel

[SilverAU]

Hi All,
I have a 2000 series 1 AU Wagon I6 that runs rough and blows black smoke after I completely fill it up. Do you think the car has a sensor problem or have I just overfilled it? The car runs fine after about 20 k's from when it was last refueled.

Great forum ! Lots of valuable info.

[svo347]

If the fuel is overflowing into the charcoal canister that'd be the problem mate.....Theres no room for the fuel to expand and pushes the fuel to the c/c
Welcome to the boards buddy

[b2tf]

What sort of fuel are you putting into it, is it regular unleaded, premium etc?

How many kms, when was last oil change?

[SilverAU]

Thanks for the welcome and the quick reply's.

SVO347: Thanks for the info. How could I check to see if the charcoal canister has fuel in it?

B2tf: Hope this helps. The car is run on V power and Optimax before that. Its been serviced regularly and has 212000 K's on the clock. Most of my driving is freeway cycle.

[b2tf]

Originally Posted by SilverAU

The car is run on V power and Optimax

well if you ask me that is your problem right there :hihi:

[SilverAU]

V power no good ?

[b2tf]

Originally Posted by SilverAU

V power no good ?

not really a fan myself but my car is a bit different to yours (see sig).

Getting back to your problem, try an oil change, change fuel filter too.

[SilverAU]

b2tf: Thanks for the info. I've just done a service, Oil change and filter etc.
I'll top the car up in the morning and see how it goes.

[Stav]

I think you arer overfilling it mate. What happens is the the return hose from the rail blocks up with fuel and has problems returning it to the tank.The result is black smoke,hesitation on acceleration .This normally clears when you use a bit of fuel

[robbo_yobbo]

sureley overfilling wouldnt be the cause. I couldnt see how the pressure in the tank could increase so much as to have the result of increasing fuel rail pressure over the fuel reg, especialy before it overflows from the filler nozzle.

The carbon canister theory makes sence, but I would have thought any increase in richness from here would be combatted by lower fuel injection as a result of the oxy sensors signal, and was under the impression the carbon canistor only cycled under certain revs/conditions.

Having said that, if it does only do it after a re-fill, those 2 theories seem like the only possibilitys, even though to me they also seem impossible.
you have an annomoly!

could it be gunk in the tank thats getting stirred up when you refill?? - no that doesnt make sence either........hmmmm

[SilverAU]

Thanks Stav. I think you and SVO347 are right as it clears itself after I've done a few K's.

It can be a bit of a buggar to fill. The pump at the petrol station clicks off when the tanks a little over three quarters full. So I keep filling it as you don't realy know when it is full. So its easy to over fill it then.

Thanks for everyones input.

[SilverAU]

I've just remembered a bit more info. It starts to play up after I've travelled about half a K from the petrol station after the refill.

[GK]

Is it possible that your fuel gauge is out and the click off when filling is actually when it's full?

I guess the answer to that question lies in how many litres does it take at the click off point and how low was the tank when you were filling.

All the best with it.

GK

[Stav]

Originally Posted by robbo_yobbo

sureley overfilling wouldnt be the cause. I couldnt see how the pressure in the tank could increase so much as to have the result of increasing fuel rail pressure over the fuel reg, especialy before it overflows from the filler nozzle.

The carbon canister theory makes sence, but I would have thought any increase in richness from here would be combatted by lower fuel injection as a result of the oxy sensors signal, and was under the impression the carbon canistor only cycled under certain revs/conditions.

Having said that, if it does only do it after a re-fill, those 2 theories seem like the only possibilitys, even though to me they also seem impossible.
you have an annomoly!

could it be gunk in the tank thats getting stirred up when you refill?? - no that doesnt make sence either........hmmmm

Try filling your car right up ok? Then slowly feed fuel into the neck until the fuel is actually right to the top of the neck and stays there without bubbles.This is where mines has the same problem with running the car.Try it.It will go away as fuel level goes lower

[EvilChief]

O2 sensor? map sensor? FPR?

[SilverAU]

Hi GK,

I do over a 100 k's a day to work and back so I tend to run the tank down to the 80 k's to go (or lower) on the trip computer. So the cars normally filled every seven days with about 80 Litres. The Pump can click off at about 45 litres so I keep filling it. So I dont think its a gauge issue.
Thanks for your input.

Hi Stav,

Yes thats exactly what happens. If I dont fill up during the normal cycle (earlier then the normal weekly fill up) and I have inadvertantly filled it up to the neck thats when it does it.

[SilverAU]

Sorry Guys I should have said 60 Litres not 80 Litres to refuel the car.

[robbo_yobbo]

Originally Posted by Stav

Try filling your car right up ok? Then slowly feed fuel into the neck until the fuel is actually right to the top of the neck and stays there without bubbles.This is where mines has the same problem with running the car.Try it.It will go away as fuel level goes lower

Im deffiniteley not nocking the theory, its one of the only 2 that seemed possible to me.

The part I just cant get my head around though is why the pressure wouldnt be released, and how it could be so great that the return line pressure is increased greater than the fuel rail as a result of it

I just figured as the fuel pump pumps fuel out of the tank into the fuel line, there would now be a negative (reduced) pressure in the tank, and would almost go so far as to create a vacuum making it easier for the excess fuel to return to the tank, and would have expected the return lines to be pretty full all the time anyway.

to me that seemed impossible, but on the other hand, its also seems like the only plausible explanation to fit the symptoms, so it tripped me out.

[SilverAU]

EviLchief, PLease explain O2 sensor ?, Map sensor ? The Fuel Pump Relay works fine !

[SilverAU]

Hi robbo_yobbo,

Yes I know what you mean
the symptoms are unreal. I was wondering if I can check the charcoal canister some how ?

[EvilChief]

Originally Posted by SilverAU

EviLchief, PLease explain O2 sensor ?, Map sensor ? The Fuel Pump Relay works fine !

any of those sensors or "fuel pressure regulator" would explain your symtoms if any of them is malfunctioning.

If the O2 sensor in your exhaust is malfunction, the ecu will be able to enter close loop cycle, which pulls down the fuel injection cycle to match as close to 14:1 AFR as possible, hence excessive fuel consumption and excessive black smoke.

If the map sensor malfunctions, the ecu is unable to determine the absolute manifold pressure and is unable to corectly caluclate the correct amount of air require for current acceleration, decelaration or cruise status, once again resulting in excessive fuel injection cycles, hence poor fuel economy and black smoke.

if the diaphrame in the fuel pressure regulator is stuffed, or vac hose fallen off, fuel pressure increases automatically to max preset pressure (around 50 to 55 psi), instead of being alternating dependant on manifold vacuume

at work i would retrieve error codes from the ecu, in order to possibly get an indication if any of the sensors is malfunctioning, i can also check of current readouts of all sensors at the time.

[robbo_yobbo]

Originally Posted by EvilChief

any of those sensors or "fuel pressure regulator" would explain your symtoms if any of them is malfunctioning..

Only problem being it doesnt explain why it only does it after a refill, or why it stops again after 20 odd k's

[EvilChief]

oh ... i thought it was permanent ... ah well

which reminds me, there is a little pressure relief solonoid close to the carbon cannister. just check if its plugged in or wires are damaged

[SilverAU]

Hi EvilChief,

I had a look at the pressure relief solenoid near the carbon cannister and the plug and wiring this afternoon. All looks OK.

Any way of testing the system?

Regards,

SilverAU.