D21 Glow plug system - electrical - solved

[fh2014]

Following on from this thread;

http://www.offroadexpress.kiwi/Forums/viewtopic.php?f=25&t=30767

I have a problem with the after-glow on my 93 terrano. Smokey as guck and missing after engine started.

First relay heats glows at full voltage before starting, second relay supposed to stay on at for 600 seconds once running, glow plugs at half voltage (unless above 20km/h or coolant above 50 deg C).

My first relay (glow) works correctly, the second relay (after-glow) switches on and off for about half a second, regardless of coolant temp or speed.

Bridged relay out and got correct half voltage at glow plugs. Must be the controller??

Anyone else had this problem?

Any ideas on a solution? (last resort manually switch this relay as I know I would always forget to switch it off)

[Crash bandicoot]

No. But the previous owner of my mistral had an aftermarket timer fitted, i suspect it is cheaper and/or easier then sourcing an oem replacement. Its probably the type of thing you want to buy new too, specially coming into winter

[ChurchurDan]

One problem with after market timers is that the the afterglow is done by pulsing the main relay. The ones we use at work only have up to 15 pulses which is not long enough. The factory systems dont give a lot of trouble so getting a second hand controller would be the easiest option.

[fh2014]

Managed to get 4 controllers. One out of a '95. All four still producing the same symptom, NO AFTER GLOW.

all power supplies good
all fuses and fuseable links good
temp sensors good
speed sensors good (if broken wouldnt affect afterglow)
all relays good
alternator signal good
start signal good
drop resistor good
surely all 4 controllers cant be bad, unless this is a really common undiscovered fault.

be interesting to test someone elses diesel terrano some day. Being a sparky i enjoy these challenges but the terrano has out done me Its time to go aftermarket, found a nice controller that has dedicated afterglow relay switch (unlike those pulsing main glow relay ones) from bogaard in aussie, price check, $230. No thankyou.

Bugger it im putting the relays on switches!!!!!!! $5-$10

p.s. if anyone needs a QGS-1 glow plug controller, I have 4. pm me.

[ChurchurDan]

I have only ever replaced one factory controller in a D21 and it lost all glow. Out of interest have you tried unplugging the temp sensor as that will make the controller think it is really cold.
Another thought I had is that the nz new D21 ute I had never had afterglow and it started and idle fine even on the coldest mornings we get here and it had 350,000 ks on it. You may have a mechanical issue causing your poor idling when cold.

[fh2014]

^Something I had considered, was just starting the slow process of figuring that out. Cheapest easiest place to start was the glows, and it failed the after glow test (according to fsm) so working to remedy.

Will bridge out afterglow relay tomorrow so I have the correct 6V on glowplug rail, then see if I still have smokey-rough cold start.

[fh2014]

New glow plugs, one was bad.

Cut the speed sensor wire and the temp sensing wire at the controller.

Controller seems to have reverted to a default - cold as - setting and runs plugs at initial warm up (12v to plugs) for the full 11-13 seconds followed by an afterglow (6v to plugs) of the full 300 seconds after starting.

Not a complete solution and not ideal when motor is hot but it starts better.