Hi,
Im trying to figure out my 12V super glow system. I used this thread for information:
But the presented information in that thread does not match up to my measurements at all.
My main problem of understanding is the voltage strap, current sensor or whatever it also might be called:
a) The green wires go to the glow plug timer and are used for voltage measurement
b) To the left the main heavy wire (directly from the glow plug relay) is connected and supplies the entire current to the glow plugs
c) To the right, the "bar" is connected which joins the 4 glow plugs.
I hope some of you recognize this strap and understand its function, since I dont.
Some info:
The strap is from a 1984 Toyota Hiace with an L engine (2,2 liter diesel engine, 4 cylinders) with the super glow system. It has 2 glow plug relays and uses the 6V or 7V glow plugs.
The car is disassembled at the moment and I am making tests using a multimeter and a powerful DC power supply (to imitate the battery) which enables me to play with all the components. I am doing a frame off restoration of the car and before disassembly I had issues with the glow plugs since starting became difficult and I needed to pre glow several times (turning key several times) before I could achieve a smooth start. With only 1 key turn the engine would shake like mad and first stabilize after 10 seconds of running and become calm.
I need to fully understand whats going on!
In the link above it is mentioned that the strap acts as a resistor having approx the same resistance as the 4 (or 6 plugs) plugs combined. Since they are connected in series, the plugs will get half the battery voltage (6-7V) and the strap will get the remaining (6-7V). So the strap enables us to use the 6-7V plugs.
My problem is, that I measure almost no resistance in the strap, it is very close to 0 ohm = it acts as a perfect conductor. In the link above it is stated that the resistance is 0,5 Ohm and I dont measure that at all!!!
When I play with my DC power supply and connect only 1 glow plug to the strap, I draw 15 Amps when cold and after 5 seconds when the plug is yellow hot it only draws 7 amps. During that test, the voltage drop across the strap is 0,07V ... almost nothing and I have the FULL voltage on the plugs and not the reduced voltage. Put it differently: If I want 6V at the plug I need to adjust my power supply to 6,07V ... and not 12V as stated in the link above.
My DC power supply does not go above 20 Amps: I cannot test all 4 plugs at the same time since that would require at least 28 Amps (4x7 Amps).
Can anyone explain what is the ups and downs in this matter?
PS: Please note: Imagine that 4 plugs get yellow hot within lets say 5 seconds. In total that should equal 4x6x7=168 Watts. If the strap should draw the same amount (50/50 split as mentioned in link), it would be VERY hot to touch. The strap has a plastic coating and NEVER gets that hot.
Lucas
Im trying to figure out my 12V super glow system. I used this thread for information:
Super Glow - explained
I have recently had a problem with my Super Glow system. During my initial diagnosis of the problem I read a great deal about Super Glow - much of it wrong, so I have drawn up a diagram of the workings of the system and done calculations to understand exactly how it works (well as close as I can...
forum.ih8mud.com
But the presented information in that thread does not match up to my measurements at all.
My main problem of understanding is the voltage strap, current sensor or whatever it also might be called:
a) The green wires go to the glow plug timer and are used for voltage measurement
b) To the left the main heavy wire (directly from the glow plug relay) is connected and supplies the entire current to the glow plugs
c) To the right, the "bar" is connected which joins the 4 glow plugs.
I hope some of you recognize this strap and understand its function, since I dont.
Some info:
The strap is from a 1984 Toyota Hiace with an L engine (2,2 liter diesel engine, 4 cylinders) with the super glow system. It has 2 glow plug relays and uses the 6V or 7V glow plugs.
The car is disassembled at the moment and I am making tests using a multimeter and a powerful DC power supply (to imitate the battery) which enables me to play with all the components. I am doing a frame off restoration of the car and before disassembly I had issues with the glow plugs since starting became difficult and I needed to pre glow several times (turning key several times) before I could achieve a smooth start. With only 1 key turn the engine would shake like mad and first stabilize after 10 seconds of running and become calm.
I need to fully understand whats going on!
In the link above it is mentioned that the strap acts as a resistor having approx the same resistance as the 4 (or 6 plugs) plugs combined. Since they are connected in series, the plugs will get half the battery voltage (6-7V) and the strap will get the remaining (6-7V). So the strap enables us to use the 6-7V plugs.
My problem is, that I measure almost no resistance in the strap, it is very close to 0 ohm = it acts as a perfect conductor. In the link above it is stated that the resistance is 0,5 Ohm and I dont measure that at all!!!
When I play with my DC power supply and connect only 1 glow plug to the strap, I draw 15 Amps when cold and after 5 seconds when the plug is yellow hot it only draws 7 amps. During that test, the voltage drop across the strap is 0,07V ... almost nothing and I have the FULL voltage on the plugs and not the reduced voltage. Put it differently: If I want 6V at the plug I need to adjust my power supply to 6,07V ... and not 12V as stated in the link above.
My DC power supply does not go above 20 Amps: I cannot test all 4 plugs at the same time since that would require at least 28 Amps (4x7 Amps).
Can anyone explain what is the ups and downs in this matter?
PS: Please note: Imagine that 4 plugs get yellow hot within lets say 5 seconds. In total that should equal 4x6x7=168 Watts. If the strap should draw the same amount (50/50 split as mentioned in link), it would be VERY hot to touch. The strap has a plastic coating and NEVER gets that hot.
Lucas