413
Member
75 TDi – 150K and a well-known remap.
A Liqi Moly diesel purge treatment two weeks ago has improved mpg, given more consistent injector value readings in VDCS and cleared some of the tractor noise from the motor but has made the tippety tappetty lifter noise a lot more noticeable - along with another mystery noise.
Waiting to see what a tin of Wynn’s hydraulic lifter treatment added to oil does to quieten the lifters but in mean time had a listen round the rocker cover and fuel pump with a stethoscope.
Top half of fuel pump (Luk) is relatively quiet but bottom half very noisy in comparison - not that I have any basis for comparison and assuming the sound isn’t being transmitted through from the engine.
Still runs okay and brakes are fine but trying to think of likely culprit and possible fixes before something goes bad.
Any reported cases of the springs in the fuel pump failing? I’m assuming from source of the noise there could be a problem with the spring at the bottom of the pump, or something worn on the central cam.
Looking at a tandem pump strip down thread (https://www.a2oc.net/community/index.php?threads/1-4-tdi-luk-038145209e-tandem-fuel-pump-rebuild.31924/) it seems like taking off the black cover plate and internal bolts would let you remove the fuel pump section while leaving the vacuum pump and seal to engine block (which isn’t leaking) intact and in situ to minimise work involved.
Figure if I get an overhaul kit that includes the proper seals, bolts and springs then should be reasonably straightforward to remove, check over the moving parts and refit. At least then can see if spring or something else internal is going bad and take it from there.
Is my thinking right on being able to just remove the fuel pump section? Any other advice?
A Liqi Moly diesel purge treatment two weeks ago has improved mpg, given more consistent injector value readings in VDCS and cleared some of the tractor noise from the motor but has made the tippety tappetty lifter noise a lot more noticeable - along with another mystery noise.
Waiting to see what a tin of Wynn’s hydraulic lifter treatment added to oil does to quieten the lifters but in mean time had a listen round the rocker cover and fuel pump with a stethoscope.
Top half of fuel pump (Luk) is relatively quiet but bottom half very noisy in comparison - not that I have any basis for comparison and assuming the sound isn’t being transmitted through from the engine.
Still runs okay and brakes are fine but trying to think of likely culprit and possible fixes before something goes bad.
Any reported cases of the springs in the fuel pump failing? I’m assuming from source of the noise there could be a problem with the spring at the bottom of the pump, or something worn on the central cam.
Looking at a tandem pump strip down thread (https://www.a2oc.net/community/index.php?threads/1-4-tdi-luk-038145209e-tandem-fuel-pump-rebuild.31924/) it seems like taking off the black cover plate and internal bolts would let you remove the fuel pump section while leaving the vacuum pump and seal to engine block (which isn’t leaking) intact and in situ to minimise work involved.
Figure if I get an overhaul kit that includes the proper seals, bolts and springs then should be reasonably straightforward to remove, check over the moving parts and refit. At least then can see if spring or something else internal is going bad and take it from there.
Is my thinking right on being able to just remove the fuel pump section? Any other advice?
