The Well-Up test is too unreliable for solid begining of delivery observation...I have tried both..It may be close sometimes and may not be close other times....This is not recommended by Bosch....The drip test is recommended by Bosch...you can use a homeade drip tube..just point it toward the engine block to reduce siphoning effect...The drip test is very close to where the fuel fill stops without trying to count drips....You are just looking for the point of plunger rise where the top edge of the plunger just blocks the barrel fill port....This point of vertical travel of the plunger is the begining of the pressurization of the sealed fuel column....For me the drip test is easier to do than the well-up test with paper towels and trying to see down in the barrel....It is very clear where the shut-off point is with the drip tube....roll the engine around several times to confirm the fuel stoppage....It is really a barrel fill complete test rather than a (drip) test......The drips just indicate that the plunger is right at the threshold of fuel fill stoppage....All of the above info assumes that the proper set up for the test is performed first....(load lever,hand pumping ,crankshaft marks etc...)

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1978 Yellow 300D (The Mustard Toad)
1980 Blue 240D (The Iron Toad)
1989 Grey Mitsu.4WD Mighty Max Pickup (Needs a Diesel transplant bad)

(Open the pod bay doors HAL)