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PD lift pump pressure
by
the caveman
on 11 Apr, 2008 08:30
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Okay first of all i can't get a straight answer whether 2005 up PD Jetta's have a lift pump in the tank. I seem to remember that at the intro course i
took that even though it wasn't shown in the booklet that the instructor said there was one. In the dealer's parts listing there wasn't one shown neither unless it was search by VIN. I asked one ex co- worker who had a newer book that showed it. I asked another mech who had scrapped one the week before and it had one in the tank. All this to ask if anbody knows waht the pressure is. I know it can't be much but i'd like some reference.
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#1
by
myke_w
on 11 Apr, 2008 14:28
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they most certainly do..
they seem to fail a good bit too..
The rail has no way to pull fuel so it has to be supplied from the tank pump
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#2
by
the caveman
on 11 Apr, 2008 15:43
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Well that's just it. I don't mean the pump on the side of the head that's driven by the cam, I mean the pump that may or may not be in the tank.
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#3
by
vwmike
on 11 Apr, 2008 15:46
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There is still a vane pump on the side of the head (known as the tandem pump) to pressurize the rail to ~100 psi. I don't know if the vane pump actually could pull fuel but I don't think it was really designed to. I have a PD150 in a MK3 Golf and run the standard gasser pump but with a bypass regulator under the car to cut it to about 3 bar and then run a non-return regulator under the hood with a gauge on it to dumb it down to about 10 psi. The tandem pump cannot regulate the inlet pressure (I know, I tested it) so it must be regulated before it reaches the tandem pump.
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#4
by
myke_w
on 11 Apr, 2008 15:48
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right, the pump on the side of the head (tandem pump) gets the fuel into the rail, the pump in the tank gets the fuel to the "tandem pump"
the in tank pump is part # 1J0 919 050
All PD's have an in tank pump.
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#5
by
Tintin
on 13 Apr, 2008 00:10
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The PD lift pump = 10-11psi.
I run mine with inline Carter 8 psi without problem, I have always 8 psi, even at full throttle and hight rpm, it provided enough GPH.
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#6
by
greg123
on 03 Aug, 2008 13:39
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We use standard Facet lift pumps on PD's that are converted to vegoil. Somewhere round the 8-10psi is good, 40106 works. Probably next pressure up better. If doing a conversion making a looped return through an alloy heat exchanger (also acts as a cooler if it gets too hot) is a great idea and works very well.
Greg.
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#7
by
the caveman
on 03 Aug, 2008 21:40
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Okay since i posted this question, i have had a customer partially install to veg system into his early production 2004 jetta PD. I supplied him with a Vegetherm [electric fuel heater from Plantdrive] and a lift pump of which i told him to install so that it pulls both diesel and VO. He did most of the installation himself [yikes ! what a mess] and came to me to redo most of the wiring and plumbing which he messed up. Long story short his car now uses the tank pump when it's on diesel and switched off with no other pump used for VO. Performance hasn't suffered and so i guess we'll see if and how long his tandem pump lasts.
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#8
by
gigaz2
on 04 Aug, 2008 04:29
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the tandem pump is able to suck the fuel from the tank, as Mike_W said, they fail a lot, an usually nobody notices it.
but it wasn't designed to work that way, who knows how long it will last.
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#9
by
greg123
on 04 Aug, 2008 05:35
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That's a very poor conversion. Not only is it straining the tandem pump, but a vegtherm is NEVER used in any pro conversion, glow plugs at 180w don't come close to the 3,000w from a decent alloy plate heat exchanger. Additionally, what is cooling the fuel back DOWN? Running the fuel back through the heat exchanger both keeps it warmed up to around 80c, but regulates the temperature back down. The PD has a big cooler from stock under the car on the return line to diesel tank, this is because the unit injectors get very hot. Diesel is the only thing lubricating them and they have electrical parts, both don't like getting overly hot. I do hope you are using a controller, because the PD unit injectors are not likely to like being left with oil in them cold if there is no auto-purge, or the user accidentally switches over to oil in the winter by mistake. The controllers have a warning buzzer if you switch off still on oil, a temperature controlled minimum switch over temperature protection and a 'purge' cycle to flush out the injectors with diesel in about 20 seconds.
Just some food for thought there.
Greg.
Okay since i posted this question, i have had a customer partially install to veg system into his early production 2004 jetta PD. I supplied him with a Vegetherm [electric fuel heater from Plantdrive] and a lift pump of which i told him to install so that it pulls both diesel and VO. He did most of the installation himself [yikes ! what a mess] and came to me to redo most of the wiring and plumbing which he messed up. Long story short his car now uses the tank pump when it's on diesel and switched off with no other pump used for VO. Performance hasn't suffered and so i guess we'll see if and how long his tandem pump lasts.
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#10
by
the caveman
on 04 Aug, 2008 10:07
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I only did what the customer asked. I also checked out what other installers are doing including the ones in Europe where they have been doing PD s for years now. I told this customer that he is a bit of a guinea pig and is okay with that. His tandem pump is brand new since he somehow sucked raw, unfiltered WVO into it to the point that it completely clogged up and failed.
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#11
by
greg123
on 04 Aug, 2008 11:02
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Your customer sounds, 'special'. How did he manage that?
? :shock:
hehehe
I only did what the customer asked. I also checked out what other installers are doing including the ones in Europe where they have been doing PD s for years now. I told this customer that he is a bit of a guinea pig and is okay with that. His tandem pump is brand new since he somehow sucked raw, unfiltered WVO into it to the point that it completely clogged up and failed.
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#12
by
jtanguay
on 08 Aug, 2008 02:10
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i would be more worried about the unit injectors than the feed pump... :shock: thick unheated unfiltered veg! :shock: in a PD?
:shock:
this is good info though... i'm converting a '98 new beetle over and need to install the lift pump. i want a nice reliable solid state pump but i can't seem to find one with the high rating... all i see available is the 4-7.5 psi pumps on ebay... i suppose i could buy two of those and see how that works??? when i had one on my 1.6TD it really makes the pressure, and is very quiet & reliable.
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#13
by
greg123
on 08 Aug, 2008 07:09
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A Facet 40107 will do the job just fine. Remember with your conversion you will be running 'closed loop' and don't have to draw anywhere near as much from the tank. So long as the tandem pump has a supply, and doesn't have to do any sucking, it's just fine.
I have actually run one with no lift pump, by accident, once. It ran just fine. So that confirmed it's just a 'supply' issue on the pump, and not a vital pressure monitered part of the fueling process - as on an HDI for instance.
Greg.
i would be more worried about the unit injectors than the feed pump... :shock: thick unheated unfiltered veg! :shock: in a PD? :shock:
this is good info though... i'm converting a '98 new beetle over and need to install the lift pump. i want a nice reliable solid state pump but i can't seem to find one with the high rating... all i see available is the 4-7.5 psi pumps on ebay... i suppose i could buy two of those and see how that works??? when i had one on my 1.6TD it really makes the pressure, and is very quiet & reliable.
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#14
by
jtanguay
on 08 Aug, 2008 12:07
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cool thanks