Forum:
i changed golwplugs
but still have problem
i have tested all of them and they all work but it seems they are not on long enough.
the plugs glow red in 3/4 secs when hard wired to battery.
but the ignition will only provide electric to the plugs for 1/2 secs and they get hot but no engough.
what controls this burn time?
the glow plug relay, on
the glow plug relay, on offside wing, has a timer built in . theres a connection to the glow plug rail between plugs 3 and 4 , by the wiggly bit, which has something to do with controling the timer...... check that connection is good and try another glow plug relay. somehow the relay drops the voltage to the plugs... think they are rated at 8 volts .
you can always turn the key on and off several times to get 3 or 4 lots of heat on the plugs before trying to start.
thnaks i have tried to switch
thnaks
i have tried to switch on and off and few times proir to starting this did not do what i expected.
where can i get a relay from non on ebay or milners.
Everyman is the architect of his own future.
Same problem here - the fix for a Fourtrak
In cold weather last year - no probs ! Always started on first attempt.
This year - refused to start.
So I bought just one Glow Plug. It had a resistance of 0.4 Ohms so peak current would be 300 Amps - gulp ! 4 of them would have a peak current of 1200 Amps !
I think there may be some resistor in the way because most batteries will not service 1200 Amps with a smile !
So I fitted using 100 Amps wire a Landrover Series starter solenoid straight from the battery to the radiator end of the glow plug copper strip. And a push button (rated 25 Amps) to the solenoid in the driver side of the dashboard.
On first start of the day, even at -10 C, I turn the ignition on and immediately press the overide push button for one second and then also start it. I release the overide as soon as it fires.
Works a treat ! Now caution must be used as serious current is reaching the plugs on 100 Amp wire which will complain after not that many seconds ! So when I say 1 second I really mean it !
Putting in this sort of overide is an absolute fix, also cheap and easy. Its not a repair. Its works fine for me as I've used it every day in the snow and vital for my existence ! Without that magic x4 button on the dashboard I shudder to think of what the last 14 days would have been like ! (work on a farm with long access track and live on top of a very steep hill half way up a mountain.)
Now anything unfused has to be treated with great respect, not wishing to catch the vehicle on fire, so if you don't feel confident of your skills with wiring, get someone who is skilled to do the mod.
Tim
Small error....
1) Tim, You've made a mistake with your current calculation.
I = V/R
Therefore, with your measured resistance of 0.4ohms:
12v/0.4ohm = 30A, and there are 4x glow plugs, so that's 4x 30A = 120A.
This implies that the 100A wire you used is not great enough, although it's only used for brief amounts of time, so would probably be ok.
2) I think glow plugs are like light bulbs - their resistance increases with temperature, so although you get a surge in current when the glow plug is cold, the current quickly reduces as the glow plug heats up.
3) The glow plug relay on the Fourtrak is controlled by a small electronic module (under dashboard / vertical wall in footwell), this measures the current flow via the two wires coming from the glow plug busbar. The module also gets the coolant temperature. To help emissions the relay, and therefore glow plugs pulse on and off as the engine warms up.
4) The glow plugs used are not 12v, but more like 7 or 8v.
5) When working correctly (as in my old Fourtrak), the engine should really start instantly as soon as the glowplug warning light goes out and the engine is cranked.
6) wertyu2007 - in your case I'd check the operation of the temperature sender (for the glow plug control module), and make sure the connections to the current measuring device on the busbar are good. Last of all I'd suspect that the control module has packed up.
1985 Veg oil burning Fourtrak "Rocky".
Many thanks for the
Many thanks for the correction ! See what happens if you spend too much time outside at -5 C !
I was suprised the wire did not show signs of stress !
So I should clean the sensor wires up on the bus. Well that a job for after Xmas.
Many many thanks for such a lucid description of whats really going on !. At the worst I know now where to take my wire cutter to under the dash board !!
Bet a Solenoid costs less than a Sensor Module !
Greatly appreciate you input !
Tim
best guess
they need replacing. buy a new one and compare it. oh no ignore thar just saw the bit you wrote, you replaced them.
Full of ideas but no time to do them!!
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Battery
Try jumping from another diesel 12v battery. Possibility your battery has a faulty plate and not providing the full ampere. Diesel batteries are of a higher ampere than petrol engines.