Bobcat 643 kubota 3 cyl diesel

[Rob64]

Machine difficult to start, recommended to replace fuel plumbing, done. new mechanical pump, removed air cleaner container, air in manifold to remove injector plumbing and injectors, replaced injectors with new ones, checked glow plugs they showed high resistance, and open, got replacement glow plugs check them for olms, and they where all three right at 1 olm each testing them found the 12volt solenoid which feeds glow power, pull in coil failed, went to auto parts store got an universal solenoid all parts put back in positions, tested and started machine all appears ok. several days later with cooler weather at our local, tried to start and used glow heat, machine finally started but didn't seem like had any glow heat. Using multi-meter found all three new glow plugs indicating open, have not modified wiring used the orig. lead from solenoid to first glow plug, than jumpers to the adjacent ones, I don't have wiring diag. for machine, so have I missed a current limiting device from solenoid, to glow plugs?

 

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did you replace the fuel pickup line into tank?

 

[Tazza]

did you replace the fuel pickup line into tank?

With the glow plugs out, hook them up to power and see if they glow right to the tip.
No current regulators, there should just be a relay that feeds +12v to the glow plug rail.
How long are you glowing?
When it's not starting, is it puffing white smoke?

 

[Rob64]

did you replace the fuel pickup line into tank?

fuel line was replaced from tank to lift pump and all return to tank plumbing, it's after the fuel line replacements I'd get white smoke and no start, after researching , glow heat seemed the route to take. ea. plug checked for olms and or continuity, all either high resistance, or open. Went to my industrial engine dealer, and got 3 replacement glow plugs ngk sheathed, 10mm threads, 12 volt, instant heat, alph and numerics matched the originals. quick test prior to installing hooked to enable solenoid, no 12 volts at out-put of solenoid, appears to be a typical 12 volt auto solenoid, replaced it with universal model from local auto parts store. after all parts installed, tested good start and all seems ok. our local weather cooling off, using data sicker on machine rops suggested 40 secs. glow preheat time, would not start, white smoke again, checked with multi-meter found high resistance or open with the three new glow plugs will go to parts house tomorrow and pick-up 3 more unless I hear from someone with another idea. It seems the auto industry, has devices to monitor current draw and modulate the power feed to plugs, so as to not over heat?

 

[Tazza]

fuel line was replaced from tank to lift pump and all return to tank plumbing, it's after the fuel line replacements I'd get white smoke and no start, after researching , glow heat seemed the route to take. ea. plug checked for olms and or continuity, all either high resistance, or open. Went to my industrial engine dealer, and got 3 replacement glow plugs ngk sheathed, 10mm threads, 12 volt, instant heat, alph and numerics matched the originals. quick test prior to installing hooked to enable solenoid, no 12 volts at out-put of solenoid, appears to be a typical 12 volt auto solenoid, replaced it with universal model from local auto parts store. after all parts installed, tested good start and all seems ok. our local weather cooling off, using data sicker on machine rops suggested 40 secs. glow preheat time, would not start, white smoke again, checked with multi-meter found high resistance or open with the three new glow plugs will go to parts house tomorrow and pick-up 3 more unless I hear from someone with another idea. It seems the auto industry, has devices to monitor current draw and modulate the power feed to plugs, so as to not over heat?

If the plugs have burnt out, ensure the solenoid isn't bad and keeping them on when the engine is running. They are not made to be able to handle running very long after the engine starts.
There is no reason for new ones to go bad so fast.