I am working on a fuel injection system and have found a wire that has broken off of what appears to be a capacitor on an in tank high pressure fuel pump assembly.
Does a replacement wire need to be insulated with something special to be immersed in gasoline all the time? I would guess so. This appears to be a circuit on a 12 volt system with two leads and a third lead wire grounded to the tank.
Dave, you are not looking for an electrical engineer (I am one.), but a chemist. I did find the following link with some information in it. Apparently you need a wire with the letter "N" in the marking label. http://electrical.about.com/od/wiringcircuitry/qt/wireinsulationtypes.htm
Every answer to every subject to anything I wanted to know in the last year for the most part, I was able to get by Googling it. It is my friend. Just last week I learned how to rebuild a carb and adjust the float properly on an 1986 Honda 4-wheeler and it even had a video with it. 8)
Lance, Google is an amazing resource. You can also find links to discussions among opinionated, uneducated contributors, of course, but these are not too difficult to sort out.
Quote from: lragan on May 09, 2013, 09:50:21 AM
Dave, you are not looking for an electrical engineer (I am one.), but a chemist. I did find the following link with some information in it. Apparently you need a wire with the letter "N" in the marking label. http://electrical.about.com/od/wiringcircuitry/qt/wireinsulationtypes.htm
Yes, I know you are an electrical engineer. That is why I was certain you would respond to my request for information. See, you did help out.
This wire code "N" seems to be the trick. I will confirm it with my wire supplier in Dallas.
Quote from: lragan on May 09, 2013, 11:13:43 AM
Lance, Google is an amazing resource. You can also find links to discussions among opinionated, uneducated contributors, of course, but these are not too difficult to sort out.
Yessir and if this was some wire hanging out in space, I wouldn't care, but in a fuel tank(?), dude, no sense becoming a "crispy critter" over 10 cents worth of the wrong wire for the job.
I am still wondering why this wire didn't arc in the tank when it got loose and start a fire/explosion. The mysteries of the universe.
Quote from: lragan on May 09, 2013, 11:13:43 AM
Lance, Google is an amazing resource. You can also find links to discussions among opinionated, uneducated contributors, of course, but these are not too difficult to sort out.
But Lawrence, the Internet sez that everything on the Internet is true.
I am sooooooo confused. (http://www.freesmileys.org/smileys/smiley-confused009.gif) (http://www.freesmileys.org/smileys.php)
Quote from: Smoked U on May 09, 2013, 11:34:48 AM
I am still wondering why this wire didn't arc in the tank when it got loose and start a fire/explosion. The mysteries of the universe.[/color]
Dave, it depends entirely on the location of the arc, when it happened, etc. If it should spark completely in the gasoline, there can be no ignition, since there is no oxygen. If in the "air" space above the tank, it is still unlikely, because the vaporizing fuel predominates, and the fuel to air ratio is way too rich.
If this were a problem there would be a lot of gas tanks blow up when the gas gauge "sender" units had wiring failures -- like the intermittent on my pickup, which from time to time goes to "empty" when there is still gas in the tank. I am pretty sure the flaw is inside the tank, since it never happens between full and 3/4 full, and I am not willing to remove the tank to get at the sender from the top.
Lazy me, I just set the trip odometer whenever I fill up. Come to think of it, that is the gas indicator I use on the Magna, too...
Quote from: lragan on May 09, 2013, 12:17:07 PM
...that is the gas indicator I use on the Magna, too...
That same indicator is the more accurate one on the Interstate too. I also like the one on the old V-65. It illuminates to indicates a "low fuel state", that is Honda speak for "Get ready to WALK".
Irgan is exactly right. I remember the first time I saw this concept was demonstrated. It was in a Power Boating Small Boating class. The instructor have a beaker of gasoline which he submerged two wires with a large gap between the tips. The wires were hooked to a battery and when he pushed the button you could see spark jump across the gap. No Oxygen no boom. when he pulled the tips above the surface and hit the button you would get a flame but since there was not a small enclosure there was no explosion. VERY IMPRESSIVE!!!!!!!!!
A popular story goes around about an Air Force mechanic working on the flight line, cleaning parts with avgas in an open tray, outside in light wind. He had a cigarette in his mouth, and when and officer barked "Airman, put out that cigarette!", he said "Yes Sir!" and stuck it into the gasoline. He understood how gasoline ignites, or was extraordinarily stupid, take your pick.
It is much more dangerous to work on an empty gasoline tank. The fuel-oxygen mixture is much more likely to be in the ignition range. When I worked on my Magna tank, I put the cap in place to seal it off, and attached a very long plastic line to the vent tube to carry fumes well away from the work area. I could then heat a small dent to try to pop it out of the tank, confident that I was not going to cause an explosion, since the flame could not contact the vapors.
Quote from: BudMan on May 09, 2013, 02:55:04 PM
Quote from: lragan on May 09, 2013, 12:17:07 PM
...that is the gas indicator I use on the Magna, too...
That same indicator is the more accurate one on the Interstate too. I also like the one on the old V-65. It illuminates to indicates a "low fuel state", that is Honda speak for "Get ready to WALK".
Greg Cothern has a funny story about this one V65 knucklehead he was riding with in Waxahachie who wasn't paying attention to the low fuel indicator and ran out of gas 1/4 mile downhill from the gas station on a very hot day. A v65 gets very heavy when it runs out of gas.
In this case, it was Honda speak for "Get ready to start pushing, Homer".