my rabbit takes forever to start when its cold but when its warm it cranks on the first hit. I think I need glow plugs how do I know if I have fast or slow ones. Its a 81 rabbit non turbo diesel...
Try using a bypass switch which forces the plugs to stay on longer. Make sure the glows are not burned out. Make sure the fuse on the firewall is not burned out.
Bump the timing up a bit.
Fast have golden tops, slows have silver tops.
my 1982 NA had slows before i changed over to the fast system. if i were to guess i'd say your car is slow glows.
check the fusable link on the firewall first...you'd be surprised it might just be that (which you can hard wire in a pinch to get the car started).
if you suspect faulty relay, wiring, or something other than the glow plugs themselves, grab some wire, a fuse (60amp i think) and jump power to the glows direct from the battery. give them power for what you think is the same amount of time as the relay would, and crank. if it starts better now then maybe its not the glows themselves, but the electrical system supporting them.
i just replaced the 2nd-cylinder plug on the weekend with the hardlines/pump still installed. i hate getting at that one! ..but it can be done.