I have a 1996 MF 1250 and its hard to start when cold. I'm getting about 9.5-10 volts to the glow plugs. Is this correct or should it be closer battery voltage which is at 12.5 volts? I get 12.5 volts into the ign switch but only 9.5-10 volts coming out to the glow plugs and to the start solenoid when in start position. seems like it should be closer to batt volts. could this be a bad ignition switch? that's what I think.
MF glow plug voltage
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CalG
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Just as likely it's a bad battery. Or only a poor battery cable connection. Check the ground strap too.
There is little likely hood that glow plug current runs through the switch. A relay is the normal way.
Turn the head lamps on when the glow plugs are on, I bet the voltage drops even more.
"Voltage" has never heated anything, It takes AMPS to make heat.
PILOON
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Otherwise said, 12 volts should get to the plugs when disconnected but when activated expect something in the 9.5 range which would be normal due to amperage draw.
Glow plugs are in reality nice resistors and they get hot!
Glow plugs are in reality nice resistors and they get hot!
well if I connect a jumper wire from the metal feed strip at the glow plug to the plug I took out it does not get red hot. same with a new one. if I jumper right to battery it gets red fast. I did not see a relay in the schematic . looks like current goes from ign sw to glow plug light {coiled wire} then to glow plugs.
CalG
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Well, that can't be how it really works. Consider the amount of current flowing through that indicator lamp.
'Can't get hundreds of watts through a 5w bulb. That's just fact.
Look for clarification on the circuit.
PILOON
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If a relay is there, then it's shot. (or your switch is acting up in the glow position)
If $$'are a main concern, simply add a good push type switch between the battery and the glow plug circuit and be the timer by counting off seconds while you acitvate the plugs. (like thousand and 1, 2 3 etc.)
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Is this like your schematic?
The indicator is not a bulb if it looks like this:
The indicator is a nichrome resistance wire and needs to be in the circuit.
CalG
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That makes sense, Another "glow plug".
If that resistor is aged and thin, it will not carry much current either.
But, check all connection before condemning the indicator. Corrosion happens! If the indicator is cheap, just replace it and see.
If that resistor is aged and thin, it will not carry much current either.
But, check all connection before condemning the indicator. Corrosion happens! If the indicator is cheap, just replace it and see.
yes that is the same glow plug indicator that I have but it doesn't glow when I hold the switch in. it used to glow but that has faded. That schematic is close but put the ign sw in place of the glow plug switch. does not show a relay. may just try to wire in a separate switch like piloon suggested
FWIW, my 2007 GC2310 also has no glow plug relay, it just goes through the ignition switch (spring-loaded turn-to-left operation). Our little SCUTS didn't come with an indicator light, either; several people have added them just to be able to tell if the circuit's actually working.
It does sound like a bad connection, however, if you can hook a GP directly to the battery and it heats up. Sounds like a simple momentary switch would be a good way to go-- just be sure it can handle the required amperage.
PS-- and yes, if that indicator glow plug is in series with the rest (as it should be) and it's flaky, that will also create the symptoms. You might try bypassing that to see if the others get hot.
It does sound like a bad connection, however, if you can hook a GP directly to the battery and it heats up. Sounds like a simple momentary switch would be a good way to go-- just be sure it can handle the required amperage.
PS-- and yes, if that indicator glow plug is in series with the rest (as it should be) and it's flaky, that will also create the symptoms. You might try bypassing that to see if the others get hot.
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