Diesel starting problem - update

I always welcome updates. Yes, you have had a lift pump replaced; being in the tank (not attached to the engine) means that it's an electric one.

Sylvain.

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What is it with this fitting of fuel pumps in the tank?

I have a petrol Rover 45 and my in tank pump failed just before Rover collapsed. The problem occurred when the temperature increased during the summer of

2003. Twice I had a problem with the pump, but I was gob smacked to learn that it sat in a pool of petrol.

I am used to working on fast jets that have their pumps suspended in AVTAG, but that is a hell of a lot less inflammable than petrol.

Are we going in the right direction here? Dave

Probably. Its a less harsh environment than outside the tank, where mud salt and water combine to corrode the shit out of it.

There are also issues about leakages and suchlike that I forget.

It's not a particularly big deal. Unless you suck the tank totally dry, the pump is totally immersed in fuel and it can't ignite anything because there's no oxygen. Even if you do expose the pump, gasoline is so volatile that the vapour space in a gas tank is almost guaranteed to be above the upper explosive limit.

The dangerous part is near the opening to gasoline containers where the vapour can mingle with air...in the fuel tank is pretty much a non-event.

Tom.

Reducing the length of the inlet pipe (or doing away with altogether?) is always a good thing. It reduces the load on the pump, and allows it to be made smaller.

Sylvain.

I think Dave is concerned that a spark from the pump could result in a big hole where the tank used to be! I too have wondered about this and assume the pump motor is a brushless design ?

Pete

Not at all. Diesel is a good spark quencher. So is petrol.

You need a very critical mixture of air and fuel to ignite. That is found ABOVE the fuel level... sometimes - but rarely. Mostly its solid vapour..but not below it. See reports on the aircraft that crashed in new york. Despite the problem being a feature of that particular aircraft, its only ever happened ONCE.

Very few cars have petrol tanks explode on impact. You can toss a cigarette into a poll of petrol and it won't ignite.

Don't believe everything you see in Hollywood films...

At what altitude?

For a good demonstration of this try pouring diesel fuel on a bonfire you're trying to light. It's really really hard to get it to burn. Chances are you won't be able to light it even if it's on paper. Forget about getting wood to light that's soaked in this stuff.

Gasoline on the other hand, when poured on a (unlit) pile of wood is downright dangerous as the vapours creep quite a long way. You drop a match on this and suddenly you find yourself in a 30' circle of instantaneous flame.

Ask me how I know.

Richard "singed eyebrows" Sexton

The message from The Natural Philosopher contains these words:

If you take the sender out of a petrol tank and supply it with 12V you can get quite noticeable sparks if you waggle the arm up and down. Doesn't matter a toss in a petrol tank as there's no appreciable amount of oxygen in there.

Is that all? I ended up with a wrecked anorak, the fire brigade and synthetic skin all over me after a dash to A & E....

There is no doubt that whilst petrol is actually very hard to light in liquid form - as is diesel - once vaporised in a nice heavy cloud with a decent concentration gradient, a match will certainly set it off many feet away. I was about 15 feet from the petrol soaked bonfire, squatting down lighting a paper dart to throw at it from what I thought was a safe distance.....

Keep in mind that 30' circle of fire that a second later was a 20' tall mushroom cloud of flames came from one cup (about 300 ml) of gasoline.

Apparantly it would have been one helluva photograph, me walking away with this giant fireball behind me.

The stuff is unbelievably potent.

Oh - I tipped a couple of pints on. MY ball was bigger than YOUR ball.

I didn't actually see it. I was covering what was left of my face with my hands and rolling around on the ground to put myself out, then into the neighbors kitchen to get hosed down.

Zero to about 50 foot, depending on the tide. It was my job to recommission them, ready for flight.

Having read other posts to my original one, I can see where I went wrong in assuming that there could be a huge explosion in a petrol tank now. The first thing that gets done to an aircraft, when it lands and taxies in, (and I had forgotten this) is it gets fully fuelled up. Thus reducing the fuel laden air in the tanks.

Many thanks to all

Dave

In article , Dave writes

It's petrol vapour that is a real problem/danger not liquid petrol.

In article , The Natural Philosopher writes

What kind of complete idiot does this?

No doubt there were children standing around...

You should be locked up to protect the public.

One hwo ws fully aware of te anegrs, or so he thought.

No, there was no one withing 50 yards

You should shove your finger up your arse and wiggle it about.

15', you were lucky! I used a bit of burning paper on the end of a broomstick and laid down flat. Quite a loud bang considering the lack of space confinement. Like the paper dart idea though - much more elegant than a broomstick :o)

In article , Bob Mannix writes

You think it is a joking matter?

It seems to be the case that the more time there is between the dispensing of the petrol and its ignition, the greater the hazard (and yes, I do understand why this might be).