Glow Plug Issues

[SamMu93]

My truck has been smoking in the mornings alot and on cold mornings it is horrendous!
So I checked the glow plugs, they are fine.
Tested the voltage to them- nothing!
Found the relay for the glow plugs... This is the start of the fault.
The contacts have 12v on one side and nothing on the other- thats fine
The coil should have 12v between the two coil pins, BUT it does not.
It has a constant 12v on one pin when you test each one to negitive.
That tells me the other pin on the coil is the negitive and is the switched one.
With all that in mind, does anyone know where/what controls the timing of the glow plugs? Which would switch this negitive.

Cheers!

[geeves]

there are 3 wires on top of the thermostat housing
I think its the right hand one you need to remove.
This will make the glow light stay on for 30 seconds not 0.5 and advance the timing meaning it will knock like a door to door missionary.
Bet this stops the smoke but dont drive it hard in this setting.

[SamMu93]

I had a multi meter on the glow plugs looking for any flicker of 12v- there was nothing so I am a little hesitant to agree Ill see 12v for 30seconds after I disconnect that thermo wire.. I will try and find out.

[geeves]

The 2.8 barely needs glow plugs unless its very cold. Unless the coolant is below 5C the glow plugs are not turned on long enough to achieve anything
It might be time for new injector tips. They helped my old bighorn heaps

[SamMu93]

Ok so, I unplugged the single wire on the right of the thermo housing....
-Dash lights up for longer (5seconds)
-Glow plug relay engages for 30seconds

So, that works mint- it also almost stopped the white smoke... Almost!
Seeing as this would be idea on almost every morning and currently my glow plugs dont turn on at all, I think I will wire up an over-ride timer that is manually started (so that it doesnt run every time and I dont have to wait if the engine is warm/ I want to actually drive withing 30seconds of starting it).

[geeves]

Maybe one of the resident mechanics could pass comment on why the 4jb1 is often so smoky cold. Is it the crude cold start setup or is it just old injectors or pump setting?
Mine was bad but it also was smelly in slow convoys despite getting 8.3l/100km on a trip New second hand injectors fixed it for a few years but it was starting to smoke excessively again when I sold it. Never topped up the oil between changes and no cranckcase fumes unless it had been thrashed (hung on rev limiter for more than several minutes at a time)

[SamMu93]

That is true, I get similar economy in mine- I had another think about how to wire the timer into the current setup...
If I interrupt the wire I disconnected on the thermo housing, time the interruption for 30seconds, that should be the most simple way of manually starting the glow plug timer.
Anyone see pitfuls in this??

[geeves]

I did think about doing it on my old bighorn but ended up putting up with the smoke instead

[xfactor]

i have to glow mine twice on the key when cold or it smokes

[SamMu93]

Xfactor, unless the coolant is below 5dg as mentioned above then your doing nothing either of the times you turn the key.
You should read the post.