Voltage at glowplugs

Hooked_on_HP · Nov 8, 2008

The glow plugs on my 1900 have been taking longer to heat up. I got out the service manual and ohmed everything like they say. Everything tested fine. I started checking voltage. I have 12v going to the ign. switch. There is 11.5v coming out going to the glow plug indicator. Coming out of the indicator I have 10v. At the glow plugs I have 9.5v. These voltage tests were done with everything connected. Should I have 12v at the glow plugs. If I unhook the wire at the glow plugs I have 12v through the whole system. The wire apears to be 10 ga. solid. It is verry stiff. Any ideas
Bill

RickB · Nov 8, 2008

I would clean up all the connections in the circuit. The voltage drop you are measuring is a little excessive, I think. There will be some drop across the indicator coil, I just can't say exactly how much. If that doesn't improve things, consider a new key switch if yours is original to the tractor. .5 volt drop within the switch is a bit much if it can't be attributed to dirty connections external to the switch.

Hooked_on_HP · Nov 8, 2008

Thanks Rick. One thing I was thinking about is whether they use the same wireing harness for a 1700(2cyl) and te 1900 (3cyl). Just wondering if the extra glowplug puts much more draw on the wireing.