I drink plenty of beer so it must be some other vitamin I'm lacking.

I do not miss using the hand primer either. In fact I've never used it. Just fill the filter up before you install it. How simple.

To vent small bubbles in my fuel system I just drive it. How simple.

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2005 sport crd-SOLD No regrets

Where do they go?

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'05 Liberty CRD B100, SEGR - SOLD

'01 Beetle TDi B100, EGR delete
'83 Mercedes 240D B100, no EGR

--- SEGR Builder ---

Combustion chamber.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

When small or even large bubbles are compressed to 23000 PSI they become nonexistent as they are instantaneously driven into solution. The problem caused by air in the fuel filter and or fuel lines is that a large "chug" of air getting into the gearoter supply pump starves the IP. The gearoter is not designed to pump air and is virtually incapable of pumping air, so it just spins it's wheels and no fuel gets to the high pressure plungers, rail pressure drops, engine misfires, driver curses and wishes that he had installed that lift pump which he read about on LOST.

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Manure green 2005 CRD sport4x4, GDE Hot tune, Cat Gut, OE skids, Draw tight hitch, Duramax lift pump, 160K on multiple varieties of fuel, XM radio, Escort live with Redline, fog light mod, GPS, Icom IC7000 all band radio call sign KC9QPF, Grabber AT2s on Soft 8s, FIA grill blanket.

Well written

Joe

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Atlantic Blue 06 CRD Limited (his)
Joined by a 2000 XJ Classic (hers)

The CP3 has a fuel-return port, where the larger air bubbles in flowing fuel can be returned to the tank via the COV system - the smallest ones are super-compressed and homogenized into the fuel, shooting thru to the Rail and it's fuel-return port - as previously posted, it is the large air pockets that starve the lift pump and hi-pressure inj pump

Large pockets of air in the fuel head allow easily pumping the primer button until the air is compressed - fuel, being not compressible, makes the primer difficult to pump when the fuel head is full

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'05 CRD Limited
Pricol EGT, Boost
GDE Hot '11; EDGE Trail switched
SEGR; Provent; Magnaflow;
Suncoast T\C, Transgo Tow'n'Go switch;
Cummins LP module, Fleetguard filter, Filterminder
2.5" Daystar f, OME r; Ranchos; K80767's, Al's lifted uppers
Rubicons, 2.55 Goodyears
Four in a row really makes it go

As far as the original question, how to tell if the hand primer pump itself is bad -

I had my hand primer quit working one time (when I still had the factory filter head installed), due to dirt and debris from a bad tank of fuel that kept the check valve from seating.

It's pretty obvious - you could pump all day long and not get any pressure buildup or anything out of the vent.

I had to attach a vacuum device to the vent and literally suck enough fuel up into the filter head, such that working the primer pump again flushed the crap out of the way and got it working again.

With a working primer pump and tight fuel system, it should take less than a half-dozen strokes to build enough pressure for it to become extremely difficult to operate the primer.

That's one other reason I installed an electric lift pump - from personal experience, I know that on occasion hand primer pumps can also cause problems or fail.

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Mitchell Oates
'87 MB 300D Diamond Blue Metallic
'87 MB 300D - R.I.P. 12/08
'05 Sport CRD Stone White
Provent CCV Filter/AT2525 Muffler
Stanadyne 30 u/Cat 2 u Fuel Filters
Fumoto Drain/Fleetguard LF3487 Oil filter
V6 Airbox/Amsoil EAA Air Filter
Suncoast TC/Shift Kit/Aux Cooler
Kennedy Lift Pump/Return Fuel Cooler

retmil46: Sounds like what I do to replace the filter on my Wife's '99 TDI.
Her TDI is getting a lift pump installed when the weather is better, at least in the mid 20s, -30 is too cold.
I am tired of it cranking the extra four seconds before it starts.

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2006 Pearl Green CRD
Magnaflow 2 1/2" Cat Back
KJ Extra Leg Room Brackets, Carter Lift Pump, V6 Airbox, ORM
Fuel cooler, Oil Separator, Progard 7
Gauges EGT Boost Trans Temp Oil Pres, Michelin LXT AT2 245 70 R16
7,000# Draw Tight hitch, PML EX Deep Trans Pan
Centrifuge, SunCoast, Transgo, RAM TCM, InMotion Stage 2
Wife's 99 TDI VW Beetle