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Location:
Perth
Registered:
December 2003
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Spark in fuel tank possible?
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Fri, 22 July 2005 03:56
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I was thinking about an in tank fuel pump setup that people use when doing efi conversion. The question is, is it safe?
I know millions of modern car have this setup from the factory, but it just make me feel nervous at the thought having wires with electricity running through it hanging inside a tank full of petrol. I must admit that my knowledge of electricity is somewhat limited, is it possible to have a spark for whatever reason in a fuel tank and cause the whole setup to go KA-BOOM.
That is why I am considering the idea of external fuel pump instead, that way the only thing inside the tank is the fuel pickup with filter on the end. Also is the original steel fuel pipe ok to use in a sprinter 4age conversion.
Thanks
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Location:
Brisbane
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 04:00
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You could set up a spark plug inside a fuel tank and nothing would happen. Combustion requires fuel and air, and in the case of petrol the fuel:air ratio must in in a very specific window or nothing will happen. There is little or no air inside a fuel tank (just liquid fuel and gaseous fuel vapour) so no chance of combustion. You couldn't even light a match inside there.
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Location:
brisbane
Registered:
October 2004
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 04:18
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exactly, that is why some fuel pumps are not sealed against the petrol, it runs inside the motor. it cant burn/explode because there is no air.
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Location:
Perth
Registered:
December 2003
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 04:34
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| Quote: |
There is little or no air inside a fuel tank (just liquid fuel and gaseous fuel vapour) so no chance of combustion.
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I was thinking something along that line as well, so how about if I forgot to put the fuel cap back on when I fill up the car, would there be enough air fuel to ignite?
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Location:
Brisbane
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 04:38
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Just outside the filler, maybe. Inside the tank, no.
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Toymods member
I supported Toymods
Location:
Rydalmere, NSW
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 07:14
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Inside the fuel tank is like a pressurised chamber, which the gas is let out instantaneously if you've run your car, shut it off at a fuel station (for example), and opened the filler cap. Dump in the fuel amongst the fuel pump, sender and all associated gauge wires, etc. which reside inside of most modern car's fuel tanks, and when you put the fuel cap back on and start the car, it takes no time at all for it to re-pressurise.
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Location:
Forrestdale W.A.
Registered:
October 2004
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Re: Spark in fuel tank possible?
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Fri, 22 July 2005 09:29
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I have just put a pump in a standard sprinter tank, I cut the top out of a damaged Pintara tank and welded it in the sprinter one along with an internal surge/swirl pot. PM me and I'll send you the pics. I have also upgraded the fuel line to 8mm (6mm standard) to prevent any flow issues, use the old 6mm line as your return to tank line. I have done the internal pump as I had huge fuel surge issues with anything less than 1/3rd of a tank with the externally mounted fuel pump.
Cheers
Mark
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Location:
Bottom of the hill, Sydney
Registered:
April 2004
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Re: Spark in fuel tank possible?
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Sat, 23 July 2005 11:51
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Blackers: How did you prepare the tank to weld in the pintara top. What precautions did you take while cutting and welding and what type of welding did you use (ie arc, mig, tig).
Basically I want to know how you welded the tank without it going BOOM.
Also if you could send some pics to bradw@swiftdsl.com.au that would be great.
Sorry for hijacking the thread.
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Banned by his request
Location:
moved to tamworth
Registered:
July 2002
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Re: Spark in fuel tank possible?
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Sat, 23 July 2005 22:22
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to degas a tank you can run a hose{large diameter} from the exhaust of a car into the filler or pump opening of the tank you have taken out.let the car idle for half hour or so and it will degas the tank.
mick
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Location:
Forrestdale W.A.
Registered:
October 2004
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Re: Spark in fuel tank possible?
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Sun, 24 July 2005 06:07
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To weld the tank you need to degas it, there are 2 ways to do this
1; take it to a professional, should cost around $100 for a motorbike, more for a car.
2; get a length of flexible tubing that fits over the tailpipe of your car (diesel is best, but any modern standard car with injection is ok, needs to have neutral emmissions, not rich like most modified cars) and stuff it over the tailpipe of the car and into the emptied fuel tank. Start the car and let it idle for 1/2hr, the warmed burnt gases from the exhaust of the car will evaporate any fuel left in the tank and the associated vapours. You can also use nitrogen gas (or any inert gas for that matter) but as they aren't warmed it takes alot longer and costs $$$. Check the tank for gas, I do this by smell after it has sat for a further 1/2 hour. It should smell of exhaust gas and not raw fuel, it may be necessary to repeat the proceedure.
Weld the tank as required but ensure it has a decent vent to atmosphere ie the cap is removed.
Piece of cake really (btw if it all turns pear shaped, I never wrote this and will deny all knowledge of the proceedure) I've done 5-6 tanks like this now. I've had a couple of queries from various people so hope this helps 
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Location:
cambo
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Sun, 24 July 2005 08:19
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you dont need to upgrade the steel fuel lines in a sprinter when going to a 4age, you dont need to upgrade them when going to a ZE or TE either, but it sure doesnt hurt.
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Location:
Bottom of the hill, Sydney
Registered:
April 2004
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Re: Spark in fuel tank possible?
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Sun, 24 July 2005 09:02
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Thanks for the info guys and thanks to Blackers for the pic.
Much appreciated
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Location:
Montrose, VIC
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Sun, 24 July 2005 10:04
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| Xinx wrote on Fri, 22 July 2005 13:56 |
That is why I am considering the idea of external fuel pump instead, that way the only thing inside the tank is the fuel pickup with filter on the end.
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Very well. But pull most external pumps apart and you'll see they work exactly the same way, with fuel running all around the brushes, commutator, etc. - if you have a problem running it INSIDE the tank, I doubt you'll feel much better with it OUTSIDE.
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Sun, 24 July 2005 10:20
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Idling a car for 30mins isn't the best for the engine  Anyway, dealing with explosive situations you are best seeing a pro, unless you are a pro, or don't value yourself.
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Location:
Arthurs Creek, Victoria
Registered:
May 2002
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Re: Spark in fuel tank possible?
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Mon, 25 July 2005 07:46
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An experiment I tried when I was younger proved that point about hte match in the gas tank thing all together.
Picture this:
14 yr old
Bucket
Petrol inside bucket, to about 1/4 full (not a HUGE bucket)
Match
Lights match, drops inside bucket.
No bang, nothing. Hardly even a flame on the top of the petrol.
All that really happened was the top layer of fuel on the miniscus was burning, but not particularly rapidly either..
Petrol is only dangerous when you airate it. IE, spread it all OVER the place to light a bon fire.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Spark in fuel tank possible?
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Mon, 25 July 2005 11:19
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two ways to do it safe..
exclude the fuel (as mentioned previously) or exclude the air..
for mine i just washed the tank with warm soapy water, and then filled tank to leave minimum air gap at top ... 5L of air is much less likely to explode (esp with such a large opening) than 50+L.... i have heard some ppl fill tanks with sand, but i think thats taking things a litle far 
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On Probation
Location:
Newcastle
Registered:
December 2004
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Re: Spark in fuel tank possible?
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Mon, 25 July 2005 12:46
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At work we dip them in the chemi-bath(caustic soda) and it strips the paint and gets rid of the fumes in the tank and then we solder them(repair them).
I work in a radiator shop.If u take it to a radiator shop they can chemi-clean it for you for about $40 bucks.It saves it exploding in front of you.You can also solder them up instead of welding.
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