84 nissan pickup sd25? glow plug help....

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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LPSTEALTH
Posts:1
Joined:8 years ago
84 nissan pickup sd25? glow plug help....

#1

Post by LPSTEALTH » 8 years ago

hey guys, mice seeing this little community here.

Well to start the story I have been fixing up an 84 pickup to drive as my winter/camping/hunting truck and ever since ive had it it has had trouble even starting on a hot day.

I checked the voltage on my glowplugs and it was showing only ~8 volts and it stayed on even after firing up the engine (it has electrical gremlins since all the wires under the dash in an attempted theft 15+ years ago)

I have now bypassed the whole system with a new relay and and posh button switch in the cab.

it does seem to start better not the 45 seconds to a minute plus ov turning over like before.

So now my question, wit ha 12 volt hotwire to the glowplugs, which are the right ones to use? I looked around and I really cant find anything so sorry if I missed a thread.

Also I read on here that some Canadian trucks had something different? Mine has 2 glow plug relays side by side under the hood if that makes a difference, (they are now bypassed).

Would these ones work? or what should I be looking for

http://www.ebay.ca/itm/4-Glow-Plugs-Nis ... 5d3283e228

Thanks for your help, Ken

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#2

Post by ehtrain » 8 years ago

ok the 2 relays are serving 2 functions for you. one relay is a glow relay to turn the glow plugs on full blast for starting

the second relay is for after glow. if your is an 84 720 as you say there will be a resistor block somewhere by the headlight i believe. This is your after glow system. it runs a large resistor inline with your glow plugs to "half" run the glow plugs to help warm the cylinder temps quicker.... thus providing smoother idle.

from my wiring diagrams your 2 relays should have 4 large wires coming to them


glow relay:
white wire - hot from battery with fuseable link (powers all the glow circuit)
white/red - relay b+ to glow plugs
blue/white(small wire) - small relay wire module + to turn relay on
black - ground

after glow:
white/blue - battery +
white/black - glow plug dropping resistor then to glow plugs
white/blue(small wire) - glow module to relay +
black - ground

if you email me i can send you a picture of the factory wiring diagram or the whole truck. dunno how to post files on here

ehtrain
Posts:141
Joined:8 years ago
Location:regina, sk

#3

Post by ehtrain » 8 years ago

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