I always figured it was a simple design but it's been a mistery to me... until last Saturday when I wasn't getting fuel on a cylinder and actually had my IP apart enough to see the Barrel and Plunger discussed in that article. Turned out to be something simple (fuel supply and return on the pump to the filter switched).

But the general function of the IP, it's not that complicated. Now the part I couldn't see, governor etc... I'm sure is VERY complicated. But the basics are just that, very basic.

I enjoyed that article on the p-pump and had to pass it on.

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-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.