Gp, resistor or just plain cold?

[Kubota Newbie]

My M4500 rattles, pops & huffs some white smoke at cold start-up. But far less than the old IH did when I was a kid. Doesn't take long to smooth out but haven't ever timed it 'cause it always seemed pretty normal for an 80's something tractor.
Mine takes about a 30 second glow around freezing, which I've always felt was reasonable (compared to the old IH 560 which at 32 still needed a little snort of ether to start even with the glow plugs). Mine takes 30 seconds before the indicator coil even begins to turn red, not really fully red-hot till almost 60 seconds (never glow it that long unless it's sub zero out). Seems to make little difference whether its 30F or -20F starts about the same, just slightly longer warm-up.
Glow plugs are maybe 2 years old.

 

[Jim L.]

Whiskey
Tango
Foxtrot

A certain amount of slack is cut for new folks, understanding that the terminology is new and that the Workshop Manual is something that they don't have.

The accuracy of the information given is direct to the accuracy of the diagnostic and suggested fix or next step.

Wolfman and others have suggested several on-point diagnostics to help get to the bottom of this issue. When the Original Poster is non-responsive or doesn't take ordinary care towards accuracy then results are not going to happen.

 

[Kubota Newbie]

For what it's worth,
My original M4500 Operator Manual says to "preheat for 40 seconds" in cold weather and 60 seconds "below -15C" (5F). Id say I rarely heat it that long.

 

[Benjaminearl]

I will post more measurements are done and checked . out. I'm not a new mechanic just a new unhappy kubota owner with buying the worst buy of my life. An idi diesel. Especially one that is obsolete as far as engine parts. Luckily a good machine shop near put some liners in and another good machine shop near me sent my head out to get welded since it had a crack into water jacket. Now I'm just sorting out coolant leaks and fuel leaks as well as starting issues and trying to put a few hours on the motor to seat the rings. It always starts just seems to smoke white more than any other diesel for longer than I'm used to. Just my opinion and observation. Now that everything is in working order the last thing on my list is to make sure glow plug are getting the exact power they need to glow correctly without melting or not getting enuf juice. I appreciate any advice given and always read everyone's response and try to answer them. Thanks again. Keep you posted to what i find

 

[BruceP]

If we are talking about the "hot wire" type of GP indicator... it has VARIABLE resistance. As it heats up and begins to glow, its resistance GOES UP hence reducing the voltage delivered to the GlowPlugs.

Here is photo of typical Kubota GP indicator ==> https://i5.walmartimages.com/asr/92....jpeg?odnHeight=450&odnWidth=450&odnBg=FFFFFF

This behavior is AS DESIGNED to prevent the GPs from burning out. The GPs receive close to battery-voltage initially...then the voltage drops as the indicator heats up and begins to glow.

Some folks have suggested replacing the indicator with a high-wattage resister or just jumpering it to send MORE voltage to the glowplugs.... doing this may end up with burned out glowplugs.

I will risk repeating myself and say that it is not unusual to glow for over 90 seconds before attempting to start engine in cold ambient temperatures. (IGNORE what the indicator is doing!!) Of-course, as mentioned in previous postings, the wiring connections MUST be clean and tight to prevent unwanted voltage drops.

 

[Benjaminearl]

Ok, at my resistor, when I turn ignition on and turn to glow I get 10.75v and output is 9.5 to start and only goes down from there as resistance increases. The indicator has a factory sticker that says s2200 which my engine is an s2600 if that is what it indicates. Although both are 6 cylinders. I think my indicator is where I lose my voltage. All glow plugs measure 1.6-1.7 ohms

 

[North Idaho Wolfman]

Sounds to me like your not putting enough volts into the indicator to start with.
That would mean bad/weak battery, bad, wiring, or bad ignition switch.

 

[Benjaminearl]

Well I did leave my key on overnight and kill my brand new battery. It's on the charger now. I've been testing. If i unhook the output of the glow switch before the indicator I get full battery voltage before the indicator. The minute I hook up the indicator the whole circuit draws down all the back to the battery.

 

[Dave_eng]

Well I did leave my key on overnight and kill my brand new battery. It's on the charger now. I've been testing. If i unhook the output of the glow switch before the indicator I get full battery voltage before the indicator. The minute I hook up the indicator the whole circuit draws down all the back to the battery.

Earlier you said the indicator was glowing when cranking.

NIW, in post #21, suggested that was not correct and perhaps you have a wiring problem.

Before re-engineering Kuubota's design by leaving out the indicator, spend some time with a wiring diagram. Do you have one?

Dave

 

[Benjaminearl]

It is not glowing while cranking. I proved my own statement incorrect. It was staying glowing but not being powered by 12v in series. I do have wiring diagram. All wiring is correct except where I changed from external regulator to alternator setup.I've been disconnecting and hunkering things to slowly but surely get to the root cause. I appreciate any and all help

 

[Dave_eng]

Do you have a WSM or just the owners`manual with the wiring diagram near the back?

Having 6 GP's is going to make the voltages and current flow much different than a 4 cyl. which is why I was wondering how much info specific to your engine you have in the form of a WSM.

Dave

 

[Benjaminearl]

I have a wsm that covers torque specs, splitting and basic maintenance. But never does it say what homages voltages should be to plugs or indicator. Wiring is per spec. I have triple checked everything. When everything is hooked up I get voltage drop of about 1-1.5volt the start of indicator. Which in turn drops it to 10.5-10v about 1.5v it seems. Every little thing like ignition and glow switch seems to add up. .3 here .4 there. So today o bypassed the indicator,I know I know not the thing to do. But when I do. I get 11.4v to start then it drops to 10.75 as it warms the plugs up after about ten seconds. Fires up better this way.

 

[North Idaho Wolfman]

In the very beginning you said new injectors, where did you get these injectors?
Directly from kubota or for other source such as eBay or amazon or others?

Have you Ohm checked each GP without the main wire connected?
I've had several New GP's fail in the first couple uses.

 

[Benjaminearl]

Injectors from a reputable injection shop here. From bosch. 1.6-1.7 ohms each.

I now realize the white smoke is normal until this beast warms up. But I would just like the glow plug circuit to be 100 percent fool proof. Everything else has been fixed 100 percent quality

 

[Dave_eng]

Ok I started it again today. Cycled plugs. This time 9-9.5c at plugs. I think my resistor is going bad. So in turn I just held the switch longer than usual. Boom it fires always does. Still smoke,but running I turn the switch back on and it sounds like it's picking up cylinders when I do that.. With a few minutes it clears up. I think the rings really need to get set in. And a new resistor to help get a consistent glow. The plugs according to ngk are 10.5v. I wish I could bypass the resistor and just hold fora few seconds instead of half minute. Valve clearances are all good. Brand new motor by great rebuild shop. They put entire motor together.

I obtained both the operators' and WSM today from my helpful Kubota dealer.

Here are the instructions for GP: 40 seconds and if colder 60 seconds.

Although I have not done any review of different models recently re glow plug times, from memory, the engines with fewer cylinders have shorter times. Others may confirm or correct me.

If the manuals I now have would help, send me a PM.

Dave