R

RicardoRich

Member
Has anybody possibly got a simplified wiring diagram so I can operate the 300tdi glow plugs direct from my NA standard ign switch , unfortunately I have to rewire from scratch. As only have wiring from bulkhead left from original.
I have traced a heavy brown , yellow from ign switch to bulkhead which I suspect maybe carries the heavy amps to the glowplugs ?
Also any ideas on how the alternator connects up please ?
I have a Haynes manual but it only shows the 300 tdi set up with relay's and timers which I don't have also the wiring colours are all different to my military loom .
Any help most appreciated as its twisting my melon .
Cheers
 
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I still run my TDi's glow plugs direct from the ign switch,holding the key to activate in the old way.
 
It is simple, I ran mine through a relay mounted behind the fuse panel to take the load off the switch though which is a bit more complicated but still easy really.
Alternator is also simple BUT I can't recall what goes where but Google will be your friend here. On the back of the alty there will be letters moulded into the casing.
The brown is battery positive which will be B+ on the alty. D is dash warning light iirc W is rev counter iirc etc etc.
 
Also, depending on your alty output, the brown wire , if original, off the NAD may not be man enough , Some 300s had much more powerful altys than the nad had. You can run another cable or double up what you have as necessary.
 
Ok cheers , .
I have wiring. Diagrams for 300 tdi. But. None of the timer relays, I want. If possible to retain the NAD,s set up. Glow plugs through first turn of ignition switch.
 
You don't need a timer relay.
The relay I fitted wasn't a timer relay just a standard one.
Imho the ign switch terminals are only just man enough to handle the glowplugs load, so the relay I fitted takes the load instead. The two heavy cables and terminals on the switch are just now used to switch the relay. A new manly cable runs from that relay to number 4 glowplug.
 
Ok cheers Flossie
I was of the belief my NAD ignition switch carried the amps through the ign switch to the glow plugs with ease ?
I was hoping not to even need to preheat very often hence the manual ign switch setup .
 
Been running my TDI's glow plugs through the ign switch since it went in ten years ago with no problem,they do not need to be on anything like the time they did with the old NA engine even in the cold weather.
 
I ran mine through a relay, live from battery to relay then to plugs, signal wire to relay from switch, live to switch isnt ignition switched so plugs can be energised before ignition. You can use a timer relay, with a 300 this is advisable.
 
tottot said:
Been running my TDI's glow plugs through the ign switch since it went in ten years ago with no problem,they do not need to be on anything like the time they did with the old NA engine even in the cold weather.
Click to expand...
Yeah, it'll most likely be fine.
I did mine with a relay because during the full rebuild, new chassis new bulkhead reconned engine etc I found heat damaged glow plug wiring for around 12" from the switch itself and the switch terminals were also heat damaged.
 
People seem to think holding the plugs in an energised state for prolonged periods is a good thing, if after 6 seconds of plugs your motor wont start you have a problem, killing your glow plugs and wiring isnt the answer to that problem.
 
Just connect na glow plug wire to 300tdi No4 plug and you are good to go.
If you use a big battery, it will start easily without using glow plugs, smaller battery struggles a bit in cold and needs help.
That is what I have found.
Test the plugs as well as you may find a few are not working if old and they are cheap.
If any are stuck solid, just leave it as you will not need all 4 to start 110.
 
When the previous owner put the 300Tdi in my 90, they never connected the glow plugs up. I was initially a little alarmed, but to be honest even at -5 the engine starts on the first revolution without any glow plugs, gives a small puff of smoke and then runs happily.
 
300tdis dont need glow plugs :) If it doesnt start in 5 seconds of cranking even if its white with frost with no glow plugs theres something else wrong.

Lots of tdi glow plugs dont work anyway and nobody notices :)
 
They do run smoother on start up if given a little heat,more so when it's below zero.
 
The main wire from the alternator goes around the driver's side of the engine, then around the back and connects with the same termina as the main battery cable on the starter solenoid.
The thin brown and yellow wire goes to the multi-plug on the drivers' side bulkhead, the same one as the stop solenoid and the temperature sender etc.

P1080759ddd.jpg
 
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