27 minutes ago, sepulchrave said:

 

I meant as opposed to LGV glow plugs which of course are 24V and wouldn't get hot enough in a 12V system, so I'm not really sure what you're on about.

 

or the 5/6V glow plugs found on a lot of later PD engines. PD105 etc.

Edited 4 April, 20206 yr by SuperbTWM

11 minutes ago, VWD said:

battery might be a bit lower than nominal 12v.

 

Even if the battery is new and fully charged, if you're taking 100+ amps down some car wiring and busbars, and cranking over a cold diesel engine say 200 amps, I doubt you'd even see 11 volts at the plug end.

 

(I measured new glowplugs at 0.3 ohms when cold on an AHU engine)

On a cold start ,there's so many things that need to be in best condition. I've never measured my car volts on starter load, but there's a couple of places where problems can happen- solenoid- any more than 0.5 volt across the high current contacts needs investigating, as does muck inside the motor, especially around the clutch.