My daughters 1981 240D is becoming a little bit difficult start. After the glow cycle, I have to give it a tiny bit of throttle for it to start. Since I am entirely new to diesels I could only guess at the fix. The car is not down on power, it's not smoky and it runs pretty much perfect once it's started.

Any clues? I have a pretty honest mechanic, but I'd like to know generally what he will be talking about when I go there.

Thank you

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1981 240D Four on the floor, Orient Red over Parchment, bought with 154,000 but it's a daily driver and up to 180,000 miles, mostly original paint and all original interior.