Glow plug wiring for 200tdi conversion

boydy1989 said:

Do early NA's have this relay? I guess they do, where is it? Or at least where is its equivalent?

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They don’t, I just wired them as per the NA from the ignition switch when I did my conversion.

My 200tdi barely needs glows though.

I have wondered about a relay circuit or a timer circuit but it seems to work fine.....

discomania said:

Right the plugs are usually about 90W - at 12V that is 7.5A - however on a cold morning with low battery voltage that could be 9A - so allow 10 per piece and you have then engineered in your safety factor.

So I would suggest a cable suitable for 40A total MINIMUM, so 4.0mm^2 or go up a size to 5.0 mm^2 cable which would be good for about 45A - you could go even further and use 6.0 for 50A.

Always fuse circuits properly and you will never have any issues - if I was building this circuit I think I would go for 50A design load.

Interestingly Land Rover used to use a 60A fuse in the 300tdi fuseboxes for these...

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Very informative thank you, I will go for that and it will definitely be fused... it’s an old v8 and they have just not bothered adding it although the glow plug harness is on plugs lol so I’ll get a glow plug relay and start from scratch including having a light in my raptor dash when it comes.

discomania said:

Also, if you have not had glow plugs since 2011 then what is the rush now? Assuming it starts OK without!

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Because I haven’t owned it since then and did notice it takes a few turns before starting when cold so I thought the glow plugs might help.

Marmaduke said:

View attachment 145375 There's someone selling the real thing on ebay for a tenner....

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That bits on lol just no wire going to as it was a old V8 it obviously never had glow plugs so will need the full look and dash light retro fitting!

joshremlin said:

Very informative thank you, I will go for that and it will definitely be fused... it’s an old v8 and they have just not bothered adding it although the glow plug harness is on plugs lol so I’ll get a glow plug relay and start from scratch including having a light in my raptor dash when it comes.

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Another option, and this is what I have, is just have a push button switch and a relay, my 300tdi only get glowed when it is 0°C or below so to be honest maybe 30-40 times a year rather than every single start up.

The correct light to use is the choke light as the earlier dashes didn't have a dedicated heater plug light. The relay I used had a telltale spade connector so I used this and it gives me visual warning that the relay has closed.

joshremlin said:

Because I haven’t owned it since then and did notice it takes a few turns before starting when cold so I thought the glow plugs might help.

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Makes sense, the plugs should help yes. I would check they work too, meter from top pin to block should be a couple of ohms, or if you have no meter, even just taking a wire from the battery to the GP harness and touch the top of one, this will power them all, do this with the cabin light on if the cabin light dips a little when you touch it you can be sure at least some of them are drawing current and at least getting somewhat hot. If you need to change them be careful, if they have not been removed for a long time they may be stuck and require care to remove them. If they break don't panic there are ways to extract them but tread carefully or your going to need to pull the head and take it to an engine re-builder/machine shop.

Also, if you go for the switch via a relay like I mentioned above you can hold the glows on after startup to get a cleaner start in very cold mornings. On the coldest days recently once started I would hold the plugs on for 30/40seconds and the white whisps of smoke disappear immediately.

With all this talk of relays, anyone have a spare 30A 10sec timer relay knocking about anywhere, because I'm too idle to look on fleabay?

Oldseadog said:

With all this talk of relays, anyone have a spare 30A 10sec timer relay knocking about anywhere, because I'm too idle to look on fleabay?

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With all the effort it took to type that sentence you could have searched for on on eBay!

discomania said:

With all the effort it took to type that sentence you could have searched for on on eBay!

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I'm just a bone idle bugger!!

Sorry to bring up an old thread (at least it shows I am researching). Anyway I’m starting my re-wire, so can anybody explain to me what No.4 actually does? It says white wire to any white wire in the harness?

Still leaves me none the wiser though lol

I believe white is ign switch. white/red is also from ign switch to starter solenoid (or relay). Just guessing it has both so glow plugs are turned off during cranking

Ok, so would it go back to the ignition via a different route? as obviously No.3 the red/white one is for the ignition, please excuse my ignorance.

I was thinking it may got to like a shared fuse or something lol, as you can see building a wiring loom from scratch with little knowledge is going to be a steep learning curve!!

Oh well, love a challenge....... what’s Auto sparks number again?

Different terminals to each other, do you have a wiring diagram? You're gonna need one

Yeah I got a couple, doesn’t mean I completely understand it though lol