Outer Limits 4x4 Board

Hey guys,

My car has been hard to start lately, with the glow plug relay clicking on and off very rapidly when it usually is glowing. 'On' position. The plugs only get a split second of power before they click off again.

I have tried my mates glow plug relay so it basically rules that out.

Could it be the timer? I tried to have a look for it, is just near the glovebox?
I pulled a circuit board out of a plastic casing behind the glovebox and when I did the thermo fan also cut out.. The loom looked like the one from the Rocky manual for the glow plug timer.
Otherwise I've got nothing.

If the timer is stuffed... are they the same as a hilux one? I know the relays are identical.

Any help is appreciated...

There's two types of glow plug pre heating systems they use.
Have a look at the rail that connects all the glow plugs together and see if there is a 'resistor ' located between plugs 3 and 4. It looks like an 'S' shape piece of flat metal with 2 black wires attached to it.
Also have a look at the front of the engine where the top radiator hose attaches. There should be 2 temperature sensors - one on the top, and one on the side (partially hidden by the top radiator hose)
If you got that resistor and the two temp sensors you've got the more modern variable time version that detects the engine temperature and varies the glow plug time accordingly.

Once you work our what version of pre heating system is used we can start to fault find, so let me know. By the sounds of your fault you've got the variable time version and it's probably the engine temperature sensor for pre heating circuit. At this stage I don't which temp sensor is for the glow plug timer and which sensor is for the temp gauge but we can work that out. I've got a 92 Rocky which should be similar to yours.

By the way I'm getting this info from the Rocky manual section ST page 22 to 30.

Stu

It would be the variable type.

The timer control module is located on the drivers side up behind the fuse box on the side panel. Silver'ish box with one plug connecting to it.

The temp sender for the timer is the one located in the lower half of the thermostat housing, not the one in the front of the head.

The resistor in the glow plug bus bar is used to determine the temperature of the glow plugs. (As the glow plugs heat up, the amount of current they draw falls, hence causing the voltage drop across this resistor to also reduce) The timer monitors the voltage across the resistor and switches the relay on and off to keep the glow plugs at a stable temp while pre-heating and prevent them from overheating.

I would go looking at the wires coming off the resistor and make sure you have continuity back to the timer box. Also check the temp sender and its connections as mentioned.

The timer boxes can die. I've replaced one before. Cost about $150 from the wreckers. Expensive I know but still better than the $280 quoted by one idiot.

Good Luck.

Cheers.

Yea, I was gunna say all that, but it would have taken me 2 pages and a lot of thinking. I can't even think of any smart comments to make, Damm!!!

Tabrocky - Do you know if these timers are sealed or can they be pulled apart? I fix electronic things from time to time, and especially since I've got a working one to compare it with, it might be possible to repair it.

Stu

Yep, a couple of screws around the metal case and your away.

Good luck.

Cheers

Okay.. I did some testing as per the manual, and I couldn't find much except the output '2' of the timer not going between 11v and 0v as stated.

I bit the bullet and it's at the auto electrician overnight. He rang not long ago saying that 3 of the glow plugs are stuffed (few months old ), and he'll put the new ones in tomorrow morning and see how it goes.
I'm not sure if faulty plugs could be making the rapid clicking though.. Here's hoping.

More news tomorrow (hopefully not me saying I need a new timer LOL)


Just re-reading tabs post earlier:

The timer monitors the voltage across the resistor and switches the relay on and off to keep the glow plugs at a stable temp while pre-heating and prevent them from overheating.

If the plugs were faulty, hopefully the could have been shorting or similar, telling the timer to switch off prematurely.

I'd say faulty plugs are a definate possibility. If sufficent current isn't being drawn through the resistor then it could be effectively telling the timer the plugs are "too hot".

Be carfull not to overtighten the glow plug terminal connection nut. I have broken plugs before from over tightening. They seem to be pretty delicate for what they are.
Perhaps I've just got a strong arm...

Cheers.

It was faulty plugs!! So happy! They are not old but must have been crap!
The auto sparky put genuine ones in for $26 each.
Could've got them cheaper through work, but didn't want to much around with it.

I'm just glad the timer wasn't stuffed... i didn't want to fork out for that.
Thanks for all your help fellas!