Check to make sure the glow plug light comes on, stays on for a while, then goes out. Don't crank until it has been off for a few seconds. Make sure voltage is going to the plugs.

If the glow system is in order, check the o-ring on the fuel inlet to the IP -- the hose will swivel. If this 0-ring is bad, fuel leaks back into the tank and air gets into the IP, causing serious hard starts, since you have to prime the IP every time.

You can test this if you can find a steep hill -- run enough to get the engine well warmed up (leaks worse hot!) then park with the nose down on the steepest grade you can (or jack the rear as high as you dare on jack stands). -- check after an hour or two -- if there is fuel on the fitting, replace the o-ring. You can do so anyway if you like, won't hurt a thing. Also check condition of the fuel line -- they tend to get brittle with age and crack underneath the fabric cover, leaking air in. Won't usually leak much fuel out.

If that is fine, blow back down the suction line witn compressed air GENTLY, with the tank cap off. You must hear air bubbling into the tank with low pressure -- if not, you have algae in the tank and need to have it cleaned. If this fixes the problem, and it comes back, ditto.

Are you having any other symptoms of low compression (excess blowby, excess smoke at full throttle, low performance, oil consumption)?

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!