5 volt problem!!!

[Cherryboo]

This is really really doing my head.
Please does anyone know why, when starting my T25, all my electrics are 5 volts till relay clicks off.
Its taking ages to start.
I have new relay, glow plugs and battery.

Thanks
Cherry

[California Dreamin]

The glow plug circuit does take quite a heavy draw from the battery so you would expect some voltage drop as the relay is operating. However, certainly NOT as low as 5 volts....I would say a reading over 10.5 volts would be normal.
So..either you have a massive short in the glow plug circuit (a main feed going straight to the body or engine) or a very poor connection somewhere.
How fast does the engine crank over? with a charged battery (once the glow plug relay has switched off) does the crank speed sound normal? (I'm not asking whether it starts)
If it cranks relatively normally then the fault is isolated to the glow plug wiring.
Martin

[Oldiebut goodie]

As above - if the glow plug circuit is shorting to earth why isn't the fuse blowing? Has the fuse been bridged with a piece of wire? Check that the insulation is still intact on the glow plug busbar especially where it goes over the coolant pipe where it can get bent down to touch the metal.