Running Rough on Low Petrol

[shane wescott]

Hi Guys

For the third time when my GTV6 has gone down to the reserve light on around 80% of the time, the car has run rough.

The solution is just to put more fuel in and run it around for 20klms or so. It then clears it's throat and all is well.

So the question is any ideas why. I did notice the pipe out of the top of the fuel tank is squished (flexible pipe, but I am not sure whether this should be flex or not. I am assuming it could be crappy fuel at the bottom of the tank or maybe a filter issue.

Before anyone asks the car is alwasy fueled with SHell Vpower, and I am a fan of Wynns Spitfire so that goes in around once every two months.

Any ideas.

Catch ya

Shane

[Brett]

Water sits on the bottom.

[a sharp]

Guys
All of the above advice is good, rule 1 for all fuel injected cars is never run the tank below 75% empty from there on it picks up the solids in the bottom of the tank, while most of the time these will clear from the injectors, sooner or later something will not and the opitions are replace the injectors or service then, (take a pile of money and hope). Yes feul is lighter then water, 1/2 cup of metho will remove this, this also helps to stop the tank rusting out, 116's are prone to this. For some reason the Classic Alfa V6 runs better on the BP top end fuel, don't ask me why but it is true and I don't know about the current V6 motors. Shell Optimax/Vpower seems to be a bit varible, I know that when Shell Aust up graded there plant that the sucessfull Japaness contractor C____ed up the design of the Cracking towers and this effected the top end products such as Optimax, I know this was a ongoing dispute, but don't know if the these problems in the plant where ever resolved 100%. Rremember drive your V6 hard but treat them with TLC as you own the best sounding motor ever, when Top Gear refer to the classic Italian V6 sound they mean a GTV6 voted the best sounding engine ever by a panel of top motor writer in europe.

[Neil Choi]

Organic Chemistry 101

As an organic chemist, I can tell you water is not lighter than petrol (hydrocarbon).  Given the density of water is 0.998 to 1 g/mL, petrol is less than that, about 0.7-0.8 g/mL, so petrol floats on water.  Here is your chemistry lesson, do this experiment, take a bottle, add some water, then add either petrol or vegetable oil, where is the water layer?  I do this type of experiment pretty much every day.

Metho or methylated spirit which is ethanol with methanol and a fouling agent (to prevent you from drinking it) added, is miscible with water, ie metho dissolves or mixes with water, such as vodka.  So putting metho in your petrol tank will take out the water condensed in there.  At low concentration, metho dissolves water, the metho or ethanol is soluble in petrol (at low concentration), so the tri-mixture is all miscible together.  Basically when you add in metho, you have made up E5 or E10!!!

Neil

[alfagtv58]

Great explanation Neil.....I had always wondered how that actually worked!!

[shane wescott]

You Guys are the font of all knowledge.

Have now filled up with BP Ultimate and will use that from now on and see how it goes.

As for the metho, interesting that they put something in it to stop people drinking it, maybe a liberal application of orange juice would mask that:-)

Anyway I will give it a go after the run down to Mirboo North this weekend.

Tank removal/cleanout is on the list as soon as the 75 is on the road.

Thanks for your help Guys.

Catch ya

Shane

[Sheldon McIntosh]

As for the metho, interesting that they put something in it to stop people drinking it, maybe a liberal application of orange juice would mask that:-)

Anyway I will give it a go after the run down to Mirboo North this weekend.

So, how did it go with the orange juice?  I reckon raspberry cordial is more effective myself.

[shane wescott]

only just got home now.

I had such a great time on the EMR that it has taken a crowbar to get me out of the car of it when i got home. Luckily the Wie needed milk so I got to do one last quick run up to the shops.

Unfortunatly when i got home the cupbboard was bear as far as metho goes:-)  I think the orange juice or the red cordial would be the go, but also maybe even Red Bull - a Red Bull and metho to kick off the night:-)

Anyway I am writing a book about pubs so may also write a book about Metho Cocktails- just need someone the test drive them for me:-)

Catch ya

Shane

[Beatle]

1.  You have a problem.

2.   Fix the problem rather than come up with a variety of ways to work around it 

I'd begin by cleaning out the tank.  I suspect you have a buildup of crud in the tank, and the fuel cleaner has probably made it worse by dislodging years of buildup.   Or there may be a bit of plastic or something loose inside the tank that only blockes the pickup with low fuel.  BTW, the metho trick will only remove so much water.  Above a certain concentration the alcohol won't mix with any more water so you will still get free water in the tank.

I suspect the real issue is a tired fuel pump.  The fuel pipe in the tank is actually a standpipe and the pump has to draw fuel up the pipe.  With a fuller tank it's easy, but with a low tank the pump may be struggling.  Check it out now so you don't end up stranded (with a full tank  )

[shane wescott]

Thanks for the advice Mate.

I have the tank removal/cleanout/replace pipes/replace pump on a list.

Ran the petrol down last week quite low to where it previously had issues, but no prob this time. The only diff was since posting the original Q on this thread I have been 100% on BP Ultimate fuel, and it seems great.

Catch ya

Shane