Ask a Car Question, Get an Answer ASAP!
I'd agree that checking the glow plugs is a good place to start
I'd check that you're getting full power to the glow-plugs, they pull a lot of current so take care when checking but see if the relay is clicking when the ignition is turned on first and also check the fuse if this is OK check to see if the engine earth strap is also OK.
If the plugs haven't been changed in the last 20K then they may have to be replaced.You can test the glow-plugs with a multimeter by measuring the resistance across the plug ( between the power connection and the body) it should be around 4-8ohms if its tending to infinity / open circuit the plug is faulty or by using a clip on current clamp, either on the supply wire to glow plugs or onto engine earth, with glow plug light on you should see 15-20amps for each glow plug fitted, 4 cylinders would be approximately 60-80amps.
on this engine the glow plugs are in the middle of the engine much like a spark plug
see the attached image