Wiring 2.5 NA or 300TDI?

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Rorie

Active Member
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641
Hi folks,

Stripping down the bulkhead ready to change it out, but the wiring is stressing me out.

I'm trying to label everything up, but its proving difficult. I am also finding that there have been a load of changes (light relays etc) that are not too easy to follow. Finally I'm finding a load of block connectors which maybe only have a couple cables going into them. I.e. a block of 8 cables on one side only has 2 cables on the other. I'm unsure if this is just additional capacity from land rover, or if things have been changed by a user?

Its a G reg defender 90 2.5N/A, but had a conversion to a 300TDI. I'm considering buying a new wiring harness to make my life a bit easier. I have seen harnesses from £50 to £1050! Not too sure exactly what I'm looking for - are there different harnesses for different parts of the car?

Also, the thing I'm really not sure of - would they have changed the harness when they did the engine conversion? Should I be looking for a 300tdi harness?

Thanks
 

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Hi Rorie , the loom could have had a 300tdi fitted or they could have modded the existing loom were needed during the engine swap depends who did the conversion .
If your after a new harness try Autosparks in Nottingham they're good got my harness of them, if you look on there web site it lists the different parts of the harness you need and they will also make a bespoke harness to your requirements . There are 3 parts to the wiring loom main, engine, and chassis harnesses .
Cheers Ian
 
Great thanks. I'll give them a shout.

There are a lot of cut and spliced wires, but not knowing what its supposed to look like, its hard to tell what I've got!

Is there an easy way to identify if its a 300tdi or 2.5NA?
 
Can't answer that but I would say the old loom was modded for the 300tdi . If you'd have asked this question in about 6 months time I could have been a bit more help as my next project is a 90 300tdi but haven't started stripping it yet , am just putting the finishing touches to my 110 200tdi that I've just rebuilt.
I might be wrong and someone will correct me if I am but I think the 2.5na didn't have a glow plug timer so you check to see if that looks like it's been added and if you can get hold of the 2 corresponding wiring diagrams check the colours of the wiring there will be differences.
But I would have thought if your buying a new loom you could just buy the 300tdi loom and fit that .
 
I know the n/a on series ones didn't have a timer it was just on how long you held the ignition not sure about 90s think depends on spec. They might not have put a timer in and either left it on ignition or disconnected most 300tdi will start below 0 without plugs
Confused me when looking at mine with all the spliced wires turns out wasn't even any plug wiring left
 
Post a pic of the engine loom.
Does the engine wiring loom plug into the standard loom with a big block connector near the diesel filter.
 
There is not much wiring to change when you put a 300tdi in a 90. If it is mounted to the original LT77 gearbox, the starter motor wiring and the heater-plug wiring stays the same, the alternator wires may need extending as may the wire to the temperature sender and the stop solenoid. There are no other engine wires.
The attached website may help you identify the wiring.
http://www.expeditionlandrover.info/Lucaswirecode.htm
 
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na think was a glass fuse system ,,,300 has spade fuse box ,,what is your fuse type
 
Not a lot of help really but when I fitted a new bulkhead to my 300 I lifted the knackered bulkhead off complete then managed to pull the steering column out in a oner and then fitted it into the new one without stripping anything off it so it saved having to label as many wires.
 
Post a pic of the engine loom.
Does the engine wiring loom plug into the standard loom with a big block connector near the diesel filter.

Yes it does. Photo of some of the blocks below. Not sure which one is the engine loom, i'd need to double check.
I've also attached a photo of one of my 'issues'. A block connector on one side, with just a couple wires sticking out the other side (link 1).

There is not much wiring to change when you put a 300tdi in a 90. If it is mounted to the original LT77 gearbox, the starter motor wiring and the heater-plug wiring stays the same, the alternator wires may need extending as may the wire to the temperature sender and the stop solenoid. There are no other engine wires.
The attached website may help you identify the wiring.
http://www.expeditionlandrover.info/Lucaswirecode.htm

I've got a disco gearbox, so must be an R380.

na think was a glass fuse system ,,,300 has spade fuse box ,,what is your fuse type

Well the fuse box was a total mess - it has spade fuses, but they are not secured in the fuse box housing, they are all over the place. So i'm not sure if someone pulled them all out so they could do more butchering post engine change, or if the glass fuses were simply swapped out?

...

With the wiring being all over the place, i'm thinking i could get a new 300tdi main harness (£150 from most places, or £500 from autosparks!). That should then suit the engine perfectly? Will everything else be the same? I.e. dashboard, lights etc?

The main harness is now out of the car, so i was going to sit down with a wiring diagram and try to identify everything. Not sure how i'll get on though!
I've found the wiring diagrams for 300tdi, but can't find the correct ones for 2.5n/a.

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The engine wiring loom should be separate from the main loom, on mine everything except the heater plugs go through one multi-plug. The base vehicle is a 1985 build military 2.5 n/a diesel. I have attached a photo where it all plugs in. (Ignore the red wire, it is the trigger for the split charge relay.)
You can see that one of the wires is white with a red stripe, which is the starter motor, the thick brown wire is the main feed for the vehicle electrics and the thin brown wire with the yellow stripe is the ignition warning lamp.
There will be three other wires;
  • Temperature sender.
  • Stop solenoid.
  • Oil pressure sender. (forgot this on my previous post.)
The thick brown wire should go from your alternator to the positive terminal on the starter solenoid, there then should be a similar wire, or two that goes from the positive terminal to the engine multi-plug.
The brown with yellow stripe wire should go from the alternator to engine multi-plug.
If there is a third thin wire on the alternator, this will be for the rev counter, I doubt that you have one.
The white and red wire should go from the engine multi-plug to the spade terminal on the starter motor.
The temperature sender wire, stop solenoid wire and oil pressure sender wire should also go to the engine multi-plug.
The engine wiring loom should be a "Y" shape and run from the alternator down the driver's side of the engine. The right hand fork of the "Y" (the thick brown wires and the white with red stripe wire) run behind the cylinder head to the starter solenoid. (Nothing goes down the exhaust side).
The engine loom picks up the temperature, oil pressure and stop solenoid wires as it runs down the side of the engine and the remaining wires make the left hand fork and go to the engine multi-plug.
The heater plugs are wired to a separate smaller multi-plug which is obscured by the fuel filter on mine.I don't have a timer, it is the standard 2.5n/a setup.


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That's great! Thanks. I'll investigate tomorrow and try to trace some wires!

So, if my engine loom hooks up fine, that means I can get a 300tdi main harness and everything should hook up easy enough? I guess everything else will be the same too?
 
Just looking at your photo of the inside of your Land Rover, there is an awful lot of 300tdi Defender stuff there, for example that,s not a Discovery gearbox unless the gear change has been replaced. I wouldn't assume that anything is from a G reg 90.
It is difficult to say without the benefit of better photos, but you may have a 300tdi Defender rather than an old 90. It could be worth getting it checked properly before you spend too much money on it, you could be repairing someone else's Land Rover.
 
Just looking at your photo of the inside of your Land Rover, there is an awful lot of 300tdi Defender stuff there, for example that,s not a Discovery gearbox unless the gear change has been replaced. I wouldn't assume that anything is from a G reg 90.
It is difficult to say without the benefit of better photos, but you may have a 300tdi Defender rather than an old 90. It could be worth getting it checked properly before you spend too much money on it, you could be repairing someone else's Land Rover.
Even if the selector housing was changed it would still sit further back, it sits just in the seatbox edge if a disco box on a 300tdi in factory position no way near bulkhead. bellhousing is longer so must be a defender box. Maybe he's thinking disco transfer
It's a good point though if it hasn't been hpi'd
 
Hmm. So that gives me more questions!

I thought Land Rover changed from a '90' to a 'Defender' in 1990. So with a G-reg, this should be the '90'?

So if i have a '90', what difference is there? I.e. why should this be an issue?

My reverse gear is below 5th gear. So according to Ashcroft, that gives me an R380. I was told when i bought it that it had a disco gearbox... maybe its a defender R380?

In the way of hpi - i ran full checks before i bought it and nothing came up, so i assume its fine! Maybe that makes me naive?

This photo shows an additional little box thats been put in next to the seat box. I assume due to a small misalignment? Photo will also give a better view of the gearbox if that helps identify things?

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You definitely have a R380, it looks to have come out of a Defender due to the position of the gear lever and your engine has the Defender hoses for the air intake, i.e. they go around the back of the engine. If it had a Discovery transfer box it would be quite high geared and would be capable of 85-90 mph without revving its nuts off.
The engine, gearbox, transfer box have serial numbers, the first three digits will tell you what they came out of, it could be worth looking at them to work out what you have.
When fitting a 300tdi in the factory position the transfer box is fitted 2" further forward than earlier vehicles, which is why you have that strange little box on the front of the seat box. A 300tdi seat box is different to earlier ones in this area, this is reassuring as it suggests that your Land Rover is an earlier vehicle that has been modified rather than a 300tdi with a G reg put on it.
 
suggests that your Land Rover is an earlier vehicle that has been modified rather than a 300tdi with a G reg put on it.

If that was a concern then checking the Chassis number would confirm whether it had been "adjusted". Also the V5 should have been updated to have the 300tdi engine number on it.
Always a good idea to get all your serial numbers, including axles, can make getting spare parts a little less hassle on a bitsa vehicle....:)

Cheers
 
@neilly off topic but do you know if the turbo- air cleaner hose will fit if you just have the half that goes off turbo? Without the second bend Thinking of using the half then mounting the cleaner on the bulkhead behind engine rarther than in factory position save messing with the silly rubber mounts and getting the brackets
 
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