Glow plugs not so glowing
- Thread starter Selkirk_D
- Start date
Wolfman, not discounting what you said. I’ll get to those tests soon
within .25 volts ? they should be the same
that suggests corroded or bad cables, wiring or connections.
that suggests corroded or bad cables, wiring or connections.
No, it cannot be that you have 3V drop with nothing connected. There must be current flowing somewhere. If your meter current causes this voltage drop then your start switch is definitely faulty.
Maybe you should describe exactly what you do and at which two points you connect your voltmeter.
On a 35 plus year old tractor? I hear you. I’ll be cleaning some connections. For now I’m settled in the alternator case bolts as a ground point
I did that this morning. All plugs are .58-.60 ohms. Meter ground on alternator case.Poly want a cracker!
North Idaho Wolfman
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I'll repeat:
Disconnect the wire at the glow plugs and put your meter to that wire and ground and crank the tractor.
What voltage are you getting?
Pull the manual stop rod, if it's firing to quickly.
Disconnect the wire at the glow plugs and put your meter to that wire and ground and crank the tractor.
What voltage are you getting?
Pull the manual stop rod, if it's firing to quickly.
Wolfman, I’m not able to perform that test right now because I’ve already pulled the dash apart. I will tell you that with glow plugs disconnected, I get 12.5 volts into switch and 9.25 volts at glow plug connector in engine compartment with switch on pre-heat.
North Idaho Wolfman
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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Without both tests you don't have a base to go from.
Yes so far it's pointing too a bad switch, but you need both tests to confirm.
No , there should be no voltage drop as no current is flowing.
BTW , does the GP indicator glow, even a bit ?
it'd be nice to se the wiring diagram, though it should be simple like..
+ve of battery----fuse----switch----GP indicatior------Glow Plugs (4)
Tha
thanks Wolfman. Seems crazy to run that kind of current through the switch without a relay. I’ll run the other test once I get it back together. I’m guessing the only thing glowing in the circuit is the switch contacts!
So darn near 70 amps thru the switch without a relay. After 35+ years of heat and oxidation, I’m surprised it hasn’t melted down by now!
As @NIW asked what is the voltage with the ign. sw. in the crank position? The glow plug circuit goes through the glow plug in the preheat position so the voltage and current will be limited during preheat. During cranking the circuit goes directly to the glow plugs so you will get battery voltage minus any voltage drop in the circuit.
You can perform a voltage drop test by placing one lead of your voltmeter on the batt. terminal and the other on the glow plug terminal. This will tell you how much voltage drop there is across the switch. Remember there is a G1 and G2 terminal. One for preheat and one for cranking.
You can perform a voltage drop test by placing one lead of your voltmeter on the batt. terminal and the other on the glow plug terminal. This will tell you how much voltage drop there is across the switch. Remember there is a G1 and G2 terminal. One for preheat and one for cranking.