I have a 1969 220d. The other day the car would not start. It usually starts on the second try as the compression is probably low. I bought a set of new glow plugs and it still won't start. I have checked the pin style plugs on my 300cd by taking the plug out, connecting it to a battery via jumper cables. When I touch the end with the cable the tip starts to get hot, indicating that the plug is good. I tried this technique with the loop plugs and I had no reaction on the old ones or the new ones. Should this technique work with these plugs? Could all of my new plugs be bad? I would appreciate any help. thanks, andy