Loop type plugs are series, not parallel, and the fast glow pencil type are paralle. You must put the series wire and relay in if you want to go back to the series type. You will burn out the loop type glow plugs doing this too, they aren't intended to be hooked up individually.

FastLane on this site has the large base plugs and the converstion kit.

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!