So my 70' 220D has progressively gotten worse at starting up and eventually wouldnt turn over at all. I thought it was perhaps a leak coming from one of the fuel fittings next to the fuel primer pump, so after awhile of the car sitting I finally was able to replace some o-rings and washers, recharged the battery, and the car started right up but idled really high. I only let it run for about 20 seconds, went and got dressed to take it out, come back and now its back to the same problem, wont turn over at all.

Im guessing this is fuel related since my glow plugs are brand new and testing okay with the meter. Where do I start diagnosing?

Ive had this problem before and had it towed to a mechanic, he pumped the hand primer pump, jumped the battery, and it started up just fine and ran very well. So he claims the hand pump just needed to be pumped, but Ive tried pumping many times but still the engine wont turn over.

Im thinking its either dirt in the fuel system since the leak I had previously had was pretty bad and there seemed to be alot of gunk where the leak had been telling me dirt got in. Or perhaps fuel pump related?

Thanks for any help!