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#15
by
745 turbogreasel
on 31 Jan, 2013 17:04
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If I undo my out bolt, the return drains down by gravity.
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#16
by
TylerDurden
on 31 Jan, 2013 17:05
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My sedans siphon the fuel in the return line away from the IP, as does the supply line (unless there are no air leaks). So, in a manner of speaking, there is negative pressure.
But, if there is a split in an injector return jumper, it can spit fuel with each pulse of the injector pintle.
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#17
by
8v-of-fury
on 31 Jan, 2013 17:15
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If I undo my out bolt, the return drains down by gravity.
While running? And having fuel pushed out of the IP?
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#18
by
745 turbogreasel
on 31 Jan, 2013 17:21
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If I undid it while running, fuel would go everywhere, and the line would still drain down.
Drainback is prevented by air not having any way to get into the pump, but if you pump leaks, if you park your car, it will be drained back in the morning.
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#19
by
8v-of-fury
on 31 Jan, 2013 17:22
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Yeah I know.
However what you are getting at does not pertain to what I said earlier. We are not talking about over night drain back, we are talking about a leaking OUT banjo.
There is pressure in that line while running.. The fuel pump is pushing nearly as much fuel back to the tank as it brought from it in the first place.
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#20
by
hippiekiller
on 31 Jan, 2013 18:13
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Off topic somewhat, but where does one find replacement copper washers, my import supplier could not find the ones I need for my oil return thanks.
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#21
by
745 turbogreasel
on 31 Jan, 2013 18:52
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Off topic somewhat, but where does one find replacement copper washers, my import supplier could not find the ones I need for my oil return thanks.
Anneal themas mentioned earlier in this thread, try a turbo or hydraulic shop.
Yeah I know.
However what you are getting at does not pertain to what I said earlier. We are not talking about over night drain back, we are talking about a leaking OUT banjo.
There is pressure in that line while running.. The fuel pump is pushing nearly as much fuel back to the tank as it brought from it in the first place.
Sure, but the line is more than big enough. No clamp, and it doesn't leak, though the braided ones will if they are too old.
If there was appreciable backpressure, it would ruin your dynamic advance.
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#22
by
libbydiesel
on 31 Jan, 2013 18:56
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Consider the diameter of the orifice in the OUT bolt and the ID of the return line itself.
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#23
by
8v-of-fury
on 31 Jan, 2013 19:25
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Consider the diameter of the orifice in the OUT bolt and the ID of the return line itself.
I am just saying, regardless without a crushed washer.. there is no seal.
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#24
by
745 turbogreasel
on 31 Jan, 2013 19:45
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The crush washer is upstream of the out bolt, and has little to do with the return line.
It sees full case pressure at all times, and must be sealed.
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#25
by
libbydiesel
on 31 Jan, 2013 20:01
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That is incorrect. The crush washers are outside the OUT bolt and so see zero pressure. The oil pan gasket is similarly under no pressure. In either case, if there is a hole it will leak and make a mess I'm not trying to say the crush washers are unimportant. They need to seal. They just aren't holding back internal pressure (or any pressure at all for that matter) and neither are the injector jumpers and so although leaks are not uncommon, it doesn't take much to make them seal. If the OUT bolt screen were plugged and internal pressure went through the roof, the likelihood of the crush washers leaking would not be increased any. If there is an issue of increased pressure at the injector jumpers or crush washers then it is due to a restriction in the return line.
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#26
by
92EcoDiesel Jetta
on 31 Jan, 2013 20:47
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That is incorrect. The crush washers are outside the OUT bolt and so see zero pressure. .....
I don't think so. The threads of the out bolt leads directly to the inside of the pump and sees internal fuel pressure.The copper washer's job is to seal the out bolt threads.
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#27
by
745 turbogreasel
on 01 Feb, 2013 00:14
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Libby is right, but I wonder if worn threads affect internal pressure?
Even so, the plunger one seals way more pressure without being all that tight.
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#28
by
theman53
on 01 Feb, 2013 05:03
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The OP needs to come back and tell us what is up. I suggested the copper washers as he hinted at them first post. My thinking is if you don't tighten the out bolt the fuel will come up the threads of the bolt and leak out a bit. He may have fixed it by adding new line like I told him could be the problem and is just embarassed to post up as it was simple.
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#29
by
92EcoDiesel Jetta
on 01 Feb, 2013 08:36
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I was referring to the copper washer between the pump case and the bolt/pedestal. If you take that bolt/pedestal out, you see internal case pressure. How can that copper washer not see pressure unless the threads forms a perfect seal? Help me out please!