ECR Posted June 19, 2013 Author Share Posted June 19, 2013 Ignore the cigarette (it's a red herring ) There must be a time when there is an explosive mix of air and fuel in the tank - what about when we run out of fuel and the pump becomes exposed and starts sucking air ? Why don't sparks from the pump, or the sender for that matter, cause problems ? Peters link shows what spaks CAN do ...... Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 19, 2013 Member Share Posted June 19, 2013 I'm still trying to understand the original question. Can we limit the discussion to petrol, cars and pumps than are in the tank. In my very limited experience the fuel pump is fitted and wired from the outside of the tank. How common is it to have the wiring inside, and of those how common is it for the wiring not to be sealed? Jonathan PS: Lots more slightly-related red herrings available... Link to comment Share on other sites More sharing options...
TJG Posted June 19, 2013 Share Posted June 19, 2013 How common is it to have the wiring inside, and of those how common is it for the wiring not to be sealed? That is pretty much standard installation (or it was five years ago when I stopped playing with cars for a living) The best answer I could get from a Bosch lecturer was that a combustible vapour situation could not occur seems to work but I would never have come up with the idea . Tony Link to comment Share on other sites More sharing options...
elie boone Posted June 19, 2013 Share Posted June 19, 2013 I had a connection of a fuel punp fail inside the tank on a Volvo 460, the electic cable was a bit short putting strain on the solder witch then broke, i resoldered it and all was fine again. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted June 19, 2013 Member Share Posted June 19, 2013 Thanks Jonathan Link to comment Share on other sites More sharing options...
Jason Plato Posted June 19, 2013 Share Posted June 19, 2013 maybe this is what those "powered by fairy dust" stickers are all about ??....... maybe they are also thinking why the tank doesnt explode 😬 😬 ps - I dont know either but I suspect there is fairies and magic involved or wine ... Link to comment Share on other sites More sharing options...
tbird Posted June 19, 2013 Share Posted June 19, 2013 Quoting ECR: Ignore the cigarette (it's a red herring ) There must be a time when there is an explosive mix of air and fuel in the tank - what about when we run out of fuel and the pump becomes exposed and starts sucking air ? Why don't sparks from the pump, or the sender for that matter, cause problems ? well going back to basic question, The external connections, spades or whatever are too far apart for 12vPD to breakdown the insulation from petrol, There may be a tiny chance of a spark if one was loose but you would then need exactly the correct fuel vapour air mix around the pump which, by the very fact that no one has ever heard of a tank in a car exploding, obviously never happens. I presume the motors are brushless so where would all these hypothetical sparks originate the motor is in a can so any sparking there might be would be in a sealed or semi sealed environment so even if there was ignition of vapour in the semi sealed part of the pump it would not be catastrophic, bit like Kapok isolating Acetylene in bottles but if you look around the web a lot of people have asked the same question and no one seems to have a truly definitive answer Tim Edited by - tbird on 19 Jun 2013 11:14:20 Edited by - tbird on 19 Jun 2013 17:03:03 Link to comment Share on other sites More sharing options...
ECR Posted June 19, 2013 Author Share Posted June 19, 2013 I don't know if the motor is brushless (higher cost and controller required apparently) but the fuel sender is a simple exposed coil with a wiper so I'd have thought that sparking was a possibility there ... Anyway, thanks to all who have contributed. I now understand why 12v motors submerged in fuel don't short out and I guess I'll just have to accept that sparking is not a problem because ...it isn't Thanks again Link to comment Share on other sites More sharing options...
Jon Stewart Posted June 19, 2013 Share Posted June 19, 2013 taken from here "Fuel passing across the fuel pump's armature is subjected to sparks and arcing; this sounds quite dangerous, but the absence of oxygen means that there will not be an explosion!" I once rear ended a careless driver pulling out of a junction. His car was pushed over a timber post on the grass verge which ruptured their fuel tank. I can confirm there can be quite a large explosion when a spark and oxygen are introduced to petrol! The flames were as high as the house of the garden the car ended up in Link to comment Share on other sites More sharing options...
BBL Posted June 19, 2013 Share Posted June 19, 2013 heat + fuel + oxygen = fire If any one of these is not present in sufficient quantity, then no fire. Link to comment Share on other sites More sharing options...
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