Cold start light?

Hi, on my diesel series III there is a light, the cold start light... and wonder what it does? Now, I know on standard diesal cars this light comes on whilst the coils heat up and then go out... then you start the car.

But on my landy the light does not come on with the electrics - the oil and electric charge light do come on, I wait a few seconds then start it - it works fine, the oil and electric lights go out, but the coil / cold start light does nothing? The previous owner said if it comes on bright then there is a fault with the plugs... Is this right?

Could somebody tell me how it is SUPPOSED to work?

Thanks!

On the petrol it's wired via a switch on the choke cable and (optional, I think) a thermostatic switch in the head. Pull choke out, choke switch is on but engine switch will be off. Engine warms up, engine switch goes on, light lights up to tell you you've left the choke out. Presumably for idiots who have no idea how their engine sounds/responds as it warms up......

On a diesel it's wired across the ballast resistor for the series wired glow plugs. The ballast is there to limit the current when the plugs are cold. When cold, the glow plugs are low resistance, the applied voltage therefore appears across the ballast resistor and the light lights. When the plugs are hot they go high resistance, the voltage across the ballast disappears, the light slowly fades out and it's warm enough to go.

I'm not sure how you wire it with the more modern parallel heater plugs but I'm sure someone will tell us.....

Hi, no I simply mean when it the light supposed to come on?

Right, went out at lunch to mess and realised I have been starting the Land Rover WITHOUT plugs on...! So, what I need to know is this - is THIS the right way to start it:

1. WHEN COLD: Push engine cut off up, then turn key to Heater plugs and wait for light to go out and THEN turn heater plugs off THEN actually attempt to start with the button - or do you keep the heater plugs on when hitting the starter button?

2. WHEN WARM: simply press the button without heater plugs.

Thanks in advance!

Sorry, but you did ask
Your starting procedure is sound. Do you have a separate starter button? I've never had a diesel landy and I'm only going on the wiring diagram but it looks like there's four positions on the ignition key - off, heater plugs, power and power/starter so you can't have heaters on when starting - seems sensible to me.

WHEN COLD: Push engine cut off up, then turn key to Heater plugs and wait for light to go out and THEN turn heater plugs off THEN actually attempt to start with the button -

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Sounds about right
I too have a start button, the po replaced the ignition switch with a 3 position petrol one I wired it so that the sprung contact is the heaters rather than starter solenoid and added a starter button myself.

Is yours the same?

Hi, yes mine is the same - first position electrics, then power to engine, then heater plugs on spring resistance - so, final questions:

1. Should you hold the key in to heat the plugs until the heater light goes out or just... well for 10 seconds or what?

2. When pressing the starter button, which has been added, do you keep the heater plugs heating, ie keep the key in, or should you let that out BEFORE hitting the starter button? Or does it make any difference?

I know this might seem petty - but don't want to damage it!

Thanks!!

If your light is dark, 'tis best to start wiv the bulb check first...

Hi, light isn't dark - questions as above, thanks!

1. Should you hold the key in to heat the plugs until the heater light goes out or just... well for 10 seconds or what?

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I have new parallel plugs so the light does not dim, I give it 10 seconds then release the key (plugs off) then press the start button.

2. When pressing the starter button, which has been added, do you keep the heater plugs heating, ie keep the key in, or should you let that out BEFORE hitting the starter button? Or does it make any difference?

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I do not keep heaters going and it starts fine, I tried once with heaters on and it showed that my battery was not in tip top condition as the extra power drain of the heaters slowed the starter motor right down

Advice taken, and now working perfectly. Thanks everybody!

My cold start light doesn't come on ether, and I'm also experiencing battery drain could this be a related problem. Could i have faulty glow plugs?
By process of illumination I have fitted a new battery and alternator and still know wiser. Can anyone help?
I have a 2.25 diesel series 3.

I actually have a diesel trattor and this is what I have found.

There are two types of glow plugs fitted to a series. The first (original) have a large thumb turn on the top and the cable to the next plug comes from under a ceramic isolating collar lower down the plug body so easy to identify. They also have a curly tail when removed. The second improved type are much the same as any modern glow plug. The first type use the curly wire resistor on the bulkhead so as not to burn out. The second have a resistor built into each plug. The first type are wired in series so if plug 4 fails, the other three dont get any juice. If number 3 goes, two and one get nowt but 4 will be ok. This is why the new ones where made available.
You must identify the type of plug system you have.
The light should be dim. Mine is so dim I can only see it at night and its not even in its little slot in the speedo. It just hangs at the mo as a bare bulb. I have tried a LED bulb but there is not enough juice to light it.
If its bright then your heater plug system has a fault.
It does not go off once the plugs are hot. Niether does a modern system I think as they are simply on a timed relay.
To start your noisy bit at the front;
Turn the key until it is up against the spring tension. Your plugs are now warming. Wait upto 30 seconds (only you will know how long to wait in different temperatures for your engine).
Turn the key to start the starter motor or press the start button. When it fires let go of everything and start running round the neighbors apologising for the noisy and now smokey bit at the back.

88"short said:

My cold start light doesn't come on ether, and I'm also experiencing battery drain could this be a related problem. Could i have faulty glow plugs?
By process of illumination I have fitted a new battery and alternator and still know wiser. Can anyone help?
I have a 2.25 diesel series 3.

Click to expand...

First, Identify the type of plug system. see above post.

Hi thanks for your reply, It would appear that I have the more modern glow plugs with a nut on the top which links them together with the wires. But i still have a curly resister. Is this wright if there meant to have have there own built in resisters?
I have noticed that on one of the plugs one of the wires will no tighten against the plug as the stem of the plug turns with it. I don't know when these where last changed as I had no history with the vehicle.
Also it is really quite smokey when it cold starts , which I've heard can be linked to faulty glow plugs.
Thanks for any advice.

Glad I've got a petrol.

O.k , I think I'm getting some where. I'm getting the impression that you don't need a Ballast Resistor (which has blown) with new style glow plugs. And the battery drain is acuring due to the un changed wiring after someone had upgraded the glow plugs. I'm no professional so tell me if I'm wrong.

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88"short said:

O.k , I think I'm getting some where. I'm getting the impression that you don't need a Ballast Resistor (which has blown) with new style glow plugs. And the battery drain is acuring due to the un changed wiring after someone had upgraded the glow plugs. I'm no professional so tell me if I'm wrong.

Click to expand...

I still have the curly wire on the bulkhead with the new style plugs. It's just been wired differently so the resistor is bypassed. It seems this is the standard way of doing it. I suppose it's handy to have it there just in case.
Have a good read of this.
http://www.seriesdiesellandrover.com/Glow Plug Conversion.html

Have a read of this thtread
http://forum.landrovernet.com/showthread.php/37210-Series-Diesel-engine-heater-plugs/page2