Glow-Plug resistance

billr

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#1
These are in a Kubota model V1702-BA, a small (36hp, 106cid) I-4 diesel. The four glow-plugs, in parallel, read 4 ohms; I'm thinking this is too high and one or more are burned out. Anyone have a guess as to what resistance of a single plug should be? Obviously, I could just disconnect them and read individually, but they are kind of hard to get to.
 
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#2
the only way i have checked glow plugs is to remove them and ground one end and applied power to the other.if they got red quickly i put em back in.the only time i do this however is when i have a starting problem.if they all have the same resistance chances are they are ok.what sort of problem are you having?Al.
 

billr

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#3
Oh, lots of electrical problems! Nothing on the instrument panel works anymore, and the battery has a drain. I have put up with everything slowly deteriorating, but now it can only be started by jumpering power right down at the (Delco) starter solenoid, and using starting fluid. Once it is warm the starting fluid isn't needed, and the alternator is the only other electric device working, so the machine (a BobCat) is still quite usable. Even the Bowden (push-pull) cable for the fuel shut-off is rusted up, so I have to get out and move the valve manually to stop the engine... Back to the electrical: The solenoid that energizes the starter solenoid is shorted to ground, that's the battery drain. The main harness connectors from engine bay to cab were never fully mated, probably because several pins/sockets were damaged, some now broken off. Also one wire there is now broken off. My goal is to get it back so you can heat the plugs and just start it with the key, and have all the gauges working, and have the head/tail lights work. When I first got this beast I never thought there would be a need for head lights, but I often get behind and am finishing up my fun day after dark!
 
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#4
is there power to the glow plugs when the key is turned on?there will be a timer that controls the glow plug cycle.if you have no power to the plugs you can always hard wire power to them thru a button you can control manually.just dont hold it on for too long or you will fry the glow plugs.if this is an old diesel,say from the 80s i would think no more than 20 seconds.im sure tony or someone else versed in diesels can either confirm or correct this information.hope this helps.Al.
 

billr

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#5
No timer on this, you just hold the key in the "heat plugs" position for as long as you want. There is no power to anything right now, since the main harness connectors are hosed. This thing is really simple, like a 1950's car with no turn-signals, no ignition system, and no radio... and I even have a schematic!
 

billr

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#7
Still no guess as to current each should draw (or resistance)? With 4 ohms across all four in parallel, I'm thinking some are burned out, but don't want to remove the electric bus wires between them if I don't have to.
 
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#8
if you get resistance you got glow.ive used dabunks test lite method as well and it works.probably time to rewire your ignition switch.sounds like its pretty simple to do with or without wiring diagrams.like i said bill,just hold a testlite on the terminal and try your key.it should lite up.if it does have current to the plugs then i would start to suspect the glo plug.again,very rare they all go at the same time.Al
 

billr

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#9
Remember guys, there are four of them wired in parallel[/i]...
 

billr

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#10
Hey, am I crazy, or did a reply from Roy get "retracted"? The Sun came out enough for me to play outside, so I pulled wires from the plugs and measured them individually. Each is .8 ohm. The problem was the power wire going to the first one (they are daisy-chained), that was loose and causing high resistance to all. Now back to repairing the main harness connectors; ring-lugs and a terminal strip is looking mighty good...
 

billr

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#12
They are in parallel, now resistance from power wire to ground (through glow plugs) is <.5 ohm, those things draw quite bit of power! I wasn't really going nuts, I was just trying to determine if one (or more) was burned out without having to disconnect things.