Anyone think of applying a few psi static air pressure to the fuel tank? Maybe via a 12v air pump. Here's a 12v pressure regulated compressor that could deliver 1-2 psi continually.


Dependable portable pump is powered by 12-volt direct current and provides both pressure and vacuum capabilities. As a compressor, offers convenient source of pressurized air for nebulizing and other aerosol applications. Aspirator function aids in clearing a patient's airway and other medical suction applications. Oil-less diaphragm produces regulated compressor pressure of 0-38 PSI (0-2.7 kg/cm2) and regulated vacuum of 0-22" Hg (0-56 cmHg). Equipped with 800cc-capacity disposable plastic suction canister and disposable hydrophobic filter for overflow protection. Vacuum gauge scale, 0-30" Hg (0-76 cmHg); pressure gauge scale, 0-60 PSI 90-4 kg/cm2). 1/10 HP, motor is powered by 12VDC, 8 AMP maximum. Plugs into automobile cigarette lighter-type receptacle or the optional battery pack (shown right). Weight, 7 lbs.; dimensions, 13 ½ " L x 9" W x 6 ¾" H (excluding canister). One year warranty on materials and workmanship.


Edited by: TraceF

Nice, idea, Trace - *but* you would also be adding a constant back pressure to the fuel recirculation process and that may lead to problems in the fuel regulation of the pumps, regulation of the fuel rails, cooling of the injectors and cooling of the fuel for the EDMs. You would also be pressurizing the entire fuel system instead of the supply section from tank to pump and I'm sure that there's no anticipated pressure sealing intended or designed into the fuel recirc/return system.

One other small but very important item is that you have a plastic tank! It will not take much if any pressure before it begins deforming.

Why would anyone want to put air (oxygen) in the fuel tank other than to make a time BOMB .


I know theres a little air in the fuel.


I wouldnt want to be around when the truck is being fueled.


good luck.

Why would anyone want to put air (oxygen) in the fuel tank other than to make a time BOMB .


I know theres a little air in the fuel.


I wouldnt want to be around when the truck is being fueled.


good luck.





http://www.dieselplace.com/forum/smileys/Question.gif This post doesn't make sense. When your tank is 1/2 full what do you think is in there with the fuel? 21% O2 and 79% N.

Why would anyone want to put air (oxygen) in the fuel tank other than to make a time BOMB .


I know theres a little air in the fuel.


I wouldnt want to be around when the truck is being fueled.


good luck.





http://www.dieselplace.com/forum/smileys/Question.gif This post doesn't make sense. When your tank is 1/2 full what do you think is in there with the fuel? 21% O2 and 79% N.





Not necessarily! There is enough fuel vapor in there to keep the void area above the upper explosive limit. The slight negative pressure it takes to allow air in through the cap combined with fuel adjitation will allow enough vaporization to keep things there. But then introduce air and thats a whole different ball game.


To elaborate on what Diesel Tech stated. 2 PSI X approx. 450 sq/in surface area at the tank bottom = roughly 900 # force...... Edited by: a bear

Hey Tommy- howya been?


I guess I don't get it. I understand the plastic tank. I don't get 900# of force. The 2 psi air pressure makes 900 pounds of what kind of force?


I can simulate pressurizing a plastic fuel tank with air by leaving a plastic fuel can in my truck bed and letting the sun hit it. This is happening all over the world I would say. Venting the can releases vapor. I know this is somewhat dangerous, but certainly not as bad as with gasoline.


Where is the danger in my enclosed fuel tank?

Hi Trace,


The 900 # of force plus the fuel hydrostatic pressure would be the pressure covering the entire bottom surface of the tank. 2# per sq/in X 450 sq/in area. The tank would more than likely hold the pressure but the tank will probably swell. How much I'm not sure. May even turn out to be a no issue but I wouldn't take the chance.


The danger of the explosive mixture in the tank would mostly be when/if there is a static electricity release when placing the fill nozzle to the tank. As you said there is less chance with diesel but I still wouldn't expose myself to the possibility.

Just something to think about. You can blow the dents out of 55 gallon drums with less than 2 PSI. Try it with 5 and you better be behind cover. You would have 900 lbs. of force with the two PSI using the total area of the bottom of the tank but it adds no weight to the tank. In other words. If the tank was out on the ground with a littles less that 900 lbs. on the top you could lift that weight up until the tank ruptured with 2 PSI. A low pressure over a large area can be very impressive when it blows. Later! Frank

hows the red head?

Can you imagine what that tank would do if there was an accident and it ruptured? KABOOM!


This won't work, the 2 psi on the inlet is offset by the return line, net effect, no fluid transfer...


Edited by: hasselbach

hows the red head?


he must be still lovin' life http://www.dieselplace.com/forum/smileys/Hug.gif

Gasoline tanks for example for the fuel sensor use a wire wound resistor with a carbon wiper that senses the wire resistance as the in tank float varies with fuel level,


so this wiper is open and exposes voltage, current, and sparkes to the inside of the fuel tank. Because it is rich with fuel vapours which block all oxidizing agents (oxygen or air) there cant be an explosion.


You require 3 elements for fire, heat, fuel, and an oxidizing agent.


If you wanted to use an inert gas. a suggestion would be carbon dioxide, but then we may get ice cubes in the tank.


just a thought, good luck.

hows the red head?


he must be still lovin' life http://www.dieselplace.com/forum/smileys/Hug.gif





And the double D's. Dhttp://www.dieselplace.com/forum/smileys/Hug.gifD

hows the red head?


he must be still lovin' life <IMG id=chkImg1 onmouseover="this.style.cursor='hand'" onmouseout="this.style.cursor=''" alt="Click on image to open in new window" src="smileys/Hug.gif" name=chkImg2>





And the double D's. Dhttp://www.dieselplace.com/forum/smileys/Hug.gifD http://www.dieselplace.com/forum/smileys/Rock On.gif

I am not sure how all this works on a diesel system, but a GM vehicle with a gas engine runs a vacuum test on the tank. If you don't get the gas cap tight after refueling it can set a MIL on the dash. See link for more explanation on GM gasoline system.


http://www.asashop.org/autoinc/jan2003/techtips.cfm

hows the red head?


he must be still lovin' life http://www.dieselplace.com/forum/smileys/Hug.gif





And the double D's. Dhttp://www.dieselplace.com/forum/smileys/Hug.gifD








The 5' red head is as beautiful and healthy as ever. Thanks for asking guys http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

OK OK OK http://www.dieselplace.com/forum/smileys/Geek.gif


Here's why I asked. About ten thousand miles ago I changed my CAT pre oem 2 mic filter and noted that it was only about one third full of fuel. I resigned myself to the eventual purchase of a JK lift pump kit if and when he ever finalizes the wiring harness.


I changed the filter again a few days ago, after about 10k miles and it was practically full, except for about an inch. I wracked my brain http://www.dieselplace.com/forum/smileys/Confused.gif and the only thing I could think of was the summer heat, as high as upper 90's recently, was possibly keeping some pressure in the tank, possibly from expansion. Thus, holding the air in suspension. Hence, the cockamamy idea.


Apparentlly, this is off base. (Don't tell the red head, she thinks I am a genius). http://www.dieselplace.com/forum/smileys/Cool.gif


Anyone got any ideas?

Sounds like a good analysis, Trace. The DMax fuel filler cap vents in only. Seems logical that Summer heat would cause additional vapor pressure and some slight positive pressure in the fuel tank.

Sounds like a good analysis, Trace. The DMax fuel filler cap vents in only. Seems logical that Summer heat would cause additional vapor pressure and some slight positive pressure in the fuel tank.


OK- how do we quantify it and duplicate it ???

OK- how do we quantify it and duplicate it ???


Move to Phoenix?http://www.dieselplace.com/forum/smileys/Ermm.gif


I don't see how you can quantify and duplicate an environmental condition - seems to me that the environmental condition just indicates the positive aspects of a controlled and quantified condition (i.e. - lift pump)http://www.dieselplace.com/forum/smileys/Approve.gif

OK- how do we quantify it and duplicate it ???


Move to Phoenix?http://www.dieselplace.com/forum/smileys/Ermm.gif


I don't see how you can quantify and duplicate an environmental condition - seems to me that the environmental condition just indicates the positive aspects of a controlled and quantified condition (i.e. - lift pump)http://www.dieselplace.com/forum/smileys/Approve.gif








Damn techies http://www.dieselplace.com/forum/smileys/Geek.gif