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A few months ago I replaced the in tank lift pump & kept the old one to take apart & mess around with.  I really like the idea of the fuel pump in the tank, IMO that is where the pump should be.  the Gasser cars get hundreds of thousands of miles on in tank pumps @ high pressure, It sure seems like someone should be able to make a diesel transfer pump that could do the same.....  

 

in any case, Ive often wondered what the yellow cross thing is in the module so I took it apart & figured you guys might want to see..

 

FP Module.jpg

Top of Sending Unit 1.jpg

 

I figured someone might need to know which wires goto which pins on the inside connector.

Top of Sending Unit 2.jpg

Installed pump 1.jpg

Installed Check valve 1.jpg

 

The amount of junk on the screen really shocked me.  Im not sure where its coming from, but when I put this module into the truck (years ago) there was nothing in the bottom of the tank.  now clearly dirt is getting in somehow...........  Kind of makes me wonder if there really is nothing wrong with the pump & its just getting starved for fuel, by this filter as well as the one in the bottom of the basket that filters the fuel going up into the basket from the bottom.......  

Removed pump 1.jpg

Removed pump 2.jpg

 

Close up of the valves between the goes-outta & goes-inta

Check Valve 1.jpg

 

the two nipples on the right are the "out" & the 2 on the left are the "IN".  Im guessing the valve on the right is an anti-drainback valve.  the one that goes across the 2 Im guessing is a "bypass" or "internal regulator" kind of deal.  that keeps fuel flowing through the pump to keep it cool while its not working too hard.  IMO, this explains why the pumps dont change pitch @ all.  its because they are never truly dead headed.  Kind of makes me wonder what kind of pressures these pumps generate.  Maybe I will do some testing when I get some "free time".  LOL. 

Check Valve 2.jpg

Check Valve 3.jpg

 

This thing I dont understand...........  

Removed pump 3.jpg

 

the red pen marks are just to show what is connected to what, not an indication of flow direction....  the 90* on the right does not appear to do anything in this application.  its not connected to anything its just a 90*.  the thing that comes out of the pump & goes to what looks like an eductor is super strange.  Clearly the super large screen is where the fuel goes into the pump, but for it to turn around & come out of the small hole on the side is strange & what is the purpose of it????  this is how it is mounted so it sits on the bottom of the pump module.  is it designed to stir up the fuel in the pump module?  keep it moving or keep it from gelling up or something.............  Id love to hear some idea's....  

Removed pump 4.jpg

Removed pump 5.jpg

 

this is just the stuff I scrapped off of the screen with a screw driver.  then I used some brake cleaner & a tooth brush to clean it up.  This picture is post scraping & pre cleaning.  Not sure where all of this crap came from......... Its not showing up in the fuel filter in the Engine compartment........  

Screen Filter 1.jpg

Edited by Bobalos
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Good info...

Imo of how in tank filter gets so dirty.  Most gas stations have filters only down to 20 micron and hard telling how many station filters are in bypass mode.  And on top of your tank there is a vent with no filter at all.  Although the vent is small in size I put on a gas filter for 1968 vw but fuel filter using a chunk of hose.  

Edited by JAG1

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Thank you for the pictures and information. It's good you got in there and cleaned it up.

 

Most guys don't want the lift pump inside the tank and have modified to an after market lift pump outside the tank. I had an in tank factory lift pump like yours and found the screen about 50% clogged as well.

 

I now have mine set up for the dirt to get trapped in a large primary filter outside the tank and all factory screens have been removed. this way the filter gets changed easily enough and if the lift pump goes soft I can change it too.

 

 

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I dont want mine in the tank. If you problem with if off the tank comes or raise the bed. I lost my AD pump recently and it is a 1 hour job to replace with hiccups.

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I totally get the "external is easier" thing, but.............. IMO, it should be decades between changes so I can lift the bed to do that every 10 or 15 years.  

 

after the 2nd block mounted died on me (3 months after I got the truck), I bolted an old Mallory 140 to the frame of the truck & cut the line & I ran it like that for probably 10 years.  no kidding I have NO idea how old it was when I put it on there & it ran for 10 years.  it finally gave up the ghost & I did the "in tank retrofit", & it lasted for quite some time (5 years, 7 years.....).  I just replaced it earlier this year & it has crapped out on me so Im looking for options. ......

 

I think Im going to go with the Air Dog & call it a day, but that means I need to get rid of the internal pump.  as "luck" would have it, I threw away the original sending unit right before I replaced the in tank one earlier this year so I could not put it back into the truck.............  :(.  Now Im working on a draw straw kind of thing. 

 

I never thought that crud could be getting in through the roll over valve on the top of the sending unit.  Maybe I will stick a filter on it to keep crap out of the tank.  

 

Anyone have any idea what that fitting thing is on the bottom of the fuel pump is????  I need to find a battery so I can power the pump & see if stuff goes in or out of it....

 

thanks

Bob

 

24 minutes ago, dripley said:

I dont want mine in the tank. If you problem with if off the tank comes or raise the bed. I lost my AD pump recently and it is a 1 hour job to replace with hiccups.

How many miles/years did you get on it?

Which model do you have?

 

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8 minutes ago, Bobalos said:

I totally get the "external is easier" thing, but.............. IMO, it should be decades between changes so I can lift the bed to do that every 10 or 15 years.  

 

after the 2nd block mounted died on me (3 months after I got the truck), I bolted an old Mallory 140 to the frame of the truck & cut the line & I ran it like that for probably 10 years.  no kidding I have NO idea how old it was when I put it on there & it ran for 10 years.  it finally gave up the ghost & I did the "in tank retrofit", & it lasted for quite some time (5 years, 7 years.....).  I just replaced it earlier this year & it has crapped out on me so Im looking for options. ......

 

I think Im going to go with the Air Dog & call it a day, but that means I need to get rid of the internal pump.  as "luck" would have it, I threw away the original sending unit right before I replaced the in tank one earlier this year so I could not put it back into the truck.............  :(.  Now Im working on a draw straw kind of thing. 

 

I never thought that crud could be getting in through the roll over valve on the top of the sending unit.  Maybe I will stick a filter on it to keep crap out of the tank.  

 

Anyone have any idea what that fitting thing is on the bottom of the fuel pump is????  I need to find a battery so I can power the pump & see if stuff goes in or out of it....

 

thanks

Bob

 

How many miles/years did you get on it?

Which model do you have?

 

I bought a 165II about 8 years ago. The 1st pump lasted 4 years as did the 2nd. I did expect both to last much longer. The replacement was 165 4g. This one better last a good while or I might reconsider replacing it again.

 Back when the in tank it starting in about year. Had no fuel pressure gauge then nor knew much about fuel pressure. But Imstarted havinf issues with the fuel and took it to a shop. The only they could find  was low pressure, 5 at idle and pretty much 0 at wot. I installed a booster pump on the frame rail and ran that combination for a few years and the issues went away. I allways had that nagging feeling of what would happen if the in tank pump just quit. It may have but everything ran right. As I have stated before, ignorance is bliss.

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