1010 glow plugs burn out!!!!

[Stan Disbrow]

Hi,

I wish we lived closer, I'd come over and poke at it with you. Actually, I used to live a lot closer to you, but that doesn't help us much now!

I have a nifty recording digital 'scopemeter' that is very useful for times like this. It has two channels, so one can record the volts and the other can be used with an AC/DC current probe that clamps onto the lead (no cutting and splicing required). It would show us both readings while powering the plugs, running the starter, and after the machine was running. Handy.

I'd like to see the wiring diagram because I wonder if there is supposed to be some sort of ballast resistor in series with the plug feed that is now missing.

I know that the F350 glow plug control unit has such a resistor incorporated that looks like a piece of ribbon candy made from copper. It's meant to limit the current to the plugs. Those plugs drop resistance as they heat up so without a limiter in series, they'd run away and burn themselves out quickly.

I don't know if the 1010 plugs have the same characteristic or not. But, if they do, they would need such a limiting resistor or they'd burn out in a hurry.

I'm sitting here thinking about that and wondering if there once was such a resistor on the 1010 that is now missing due to some wiring 'repairs' in the past. Perhaps the single battery cable was acting as a ballast resistor in place of a specific one, and now it's effectively gone since there's a second battery and cable in place.

I know. This gets us to the same thought as before, but with a possible explanation as to *why* you'd trip across the problem by simply adding a second battery in parallel with the first one. It's somewhat of a stretch since I'm basing the thought on some other design I've seen. But since it did come to mind, I thought I'd pass it along in case I might be onto something here....

Later!

Stan

[Stan Disbrow]

Hi,

Ok, looking at it now. I originally thought the link was to photos of the machine, but it's a copy of the wiring diagram.

There are four 'somethings' on a lead that runs back to the key switch terminal 'GL'. I presume those are the glow plugs.

I love it when they don't use international symbols for electrical schematics. The glow plugs *ought* to look like resistors, instead of skinny rectangular 'somethings'.

I don't see a ballast resistor, which I'd expect to show up like another 'something' stuck in the wiring line from the key switch to the glow plugs.

Yet another beautiful theory torpedoed by an ugly fact. That's the nature of my professional life, all right! I *hate* when that happens!

There's another 'something' in what I figure must be the battery line to the key switch. At least it's the center terminal, which ought to be the battery feed. It's not too far from the arrow '19' is pointing at. I figure that is the fuse. Again, not the symbol for a fuse, but we've already covered that part!

There is another 'something' that '18' is pointing at. It's in the lighting circuit, though. It goes from 'A' on the key switch to the common terminal of the light switch. Another fuse? If so, then pardon my conFUSEion, since I'm used to older machines that have only one fuse. More than one is complicated!

Anyway, back to not knowing why you're seeing fast-fry glowplugs. They ought to take the 12v just fine even with two batteries. I'm still stuck with the use of the single battery cable to limit the current as my best guess....

Later!

Stan

[JD440ICD2006]

I went back and read the original post as there have many to weigh in (including me) that are shooting the dark attempting find the solution. (or decide to buy stock in the glow plug company)

If you added the 2nd battery as soon as you got it, we do not know if this was already a problem.
If the starter needs a rebuild and is drawing too many amps due to partial grounding, could that be zapping the glow plugs? How about a poor ground somewhere in the system? That would change the resistance and the whole electrical equation.

[Tigerhaze]

I'm not sure if this will help, but we had a really good discussion of testing glow plugs for the 2010 diesel (I would assume similar setup as 1010 diesel) a few years back.

http://www.jdcrawlers.com/messageboard/ ... glow+plugs

[H-D]

To my simple mind, KenP's opinion is elegant & holds the greatest probability. I worked in a GM assembly plant & we built diesels through differing year ranges on cars, or trucks. They ALL had some form of control relay & would 'time out', clunk 'off', & then clunk 'on' again when a second timer was satisfied. The factory wiring diagram IS pretty abysmal! Another bit of my teaching returned (miraculously), V= I X R. Where V is voltage, I is amperage, & R is resistance. With that (& a water hose analogy), an increase of the resistance with a sufficient amperage is going to increase the voltage (seems that this is part of how they get higher voltage in TVs). The water hose bears it out too; restrict the end of a hose with sufficient volume (valve WFO), & you'll get an increase in pressure that allows you to spray farther.
What I'm trying to work my way to, is that PERHAPS the grounding path of the glow-plugs is at a considerably higher resistance level than the design intent. Lord knows, this is a simple theory to test with a cheap voltmeter. Hot lead to battery +, negative lead at the glow plug 'shell'. A 'significant voltage drop' would indicate a problem. GM's definition of significant was anything in excess of .2 volt across any single connection. I still think KenP's 100% duty cycle theory has it nailed! It's elegant & simply tested as well. PERHAPS there is supposed to be a bi-metallic 'circuit breaker' within the master switch (like what was in an older car's light switch to protect the headlight circuit) to kill the glow-plugs when the amp draw exceeds a level which turns the glow-plugs into flash-bulbs? I'll shut up now.

[Stan Disbrow]

Hi,

But, then, a bi-metal breaker would reset once it cooled and re-energize the plugs until it warmed up again. A vicious cycle, no?

The usual method for tractor plugs is a spring loaded switch of some sort. You hold it to energize and then let it go once the engine started and the plugs go back off.

With a key switch, this is usually turn to the left, hold for 10 seconds, then turn to the right and try to start. Repeat as necessary until the fool thing either starts or you kill the battery....

I have been presuming this is how that switch depicted in the diagram works, but maybe not?

As far as a bad connection goes, this would be putting a resistance in series with a resistance and get you cooler plugs and not hotter. Using the hose theory, neck it down at the end and that represents the glow plug. Neck it down elsewhere in the hose as well, and you get less pressure at the nozzle because you have two resistances in series....

Yes, 2/10 of a volt would ba about right for a 12v system to call the drop across anything that isn't supposed to be a resistor (glow plug, light filament, etc) significant.

later!

Stan

[robk]

I have several sets of glow plugs. All have now been tested with Professor Demaris' test method discussed in the link above from Tigerhaze. All except two are bad. Those two heat up red hot almost instantly and draw 15+ amps. ONE of the rest tests GOOD with an Ohm meter but is NO GOOD in the "Demaris Bench Test" with a battery and ammeter. This at least confirms that YOU CANNOT DEPEND ON A GLOW PLUG TEST WITH A OHM METER! (At least in my mind!) I have posted my wiring diagram on Picasa (see previous post). After all this, I'm certainly going to re-wire the glow plugs from the starter switch. Many thanks you guys. I'm very grateful for any and all ideas. I will certainly keep y'all posted. Stan? The shop door's always open. I'll leave a cot in there for you. Let me know if your wife is coming. She can stay in the guest room.

[H-D]

Thanks Stan, for pointing out the obvious truth that resistances in series add up & drop current! I was just making a WAG as to the nature of the glow-plug section of the master switch. In one of my MANY mis-adventures, I had the functioning of the bi-metallic circuit breaker made known to me! It made for 'interesting' illumination, but did save the headlight harness. The law-enforcement-professional who pulled me over was not nearly so impressed though. He seemed to think that I had carted off Ft.Knox in my '49 Chevy P-U. I seriously believe that a properly regulated circuit breaker would extend the service life of the glow plugs, but then , of course they should not be exposed to a 100% duty cycle either! Thanks again for setting my wheels back on the rails!!!

[Stan Disbrow]

Hi,

Well, don't feel too badly about resistances. If you put two in *parallel* then you get an effective resistance of the two values added together divided by two. That means a lower resistance and a higher current flow.

It's easy to get the series and parallel nature mixed up, but reverting to the old water in the pipe analogy serves here as well. Two hoses laid next to each other connected to the same source will flow more water than one. You can play with that in series as well, just use different diameter hoses to represent the resistance.

Note, though, that the water and pipe analogy serves well for DC, but starts to lose it for AC. And, the higher the frequency of AC, the less it applies. You can still visualize AC, at least at the most common 60 cycles per second, as someone at the valve moving it from full off to full on and back to full off, etc. The water flows in waves, so at any given time the voltage and current are moving as well but in phases. Well, you get it now.

One of the problems with heating elements is mechanical cracking. The thing might be OK when cold, so the ohmmeter reads it as good. As soon as you apply power, though, it starts heating and the pieces move and the cracked parts - they disconnect. So, the meter says it's OK, and the real-world test says it's bad.

It's also likely that as they age, the resistance value when hot drops and so they draw more current hot than they should, leading to the bitter end for the element. This works for all heating elements, including light bulbs. well, the old, no longer desired, ones.

Of course, the element is inside the tube at the end of the plug assembly, so you can't see it to tell if it's cracking up or not. The bench test is the best method as you can then see if it's truly OK or not.

No, you can't leave them on. Not for long, anyway. If they overheat, then they will crack inside and go bad. The usual method is the reverse turning of the key and counting off a few seconds and then trying to start it. If it goes, then you're good and if it won't, then another few seconds of plugs is in order. I like the manual method better than the automatic one the trucks use.

My 2008 JD 5103 wheel tractor has no glow plugs, but has a heater inside the air intake. One pushes inwards on the key prior to turning it to engage the heaters. It actually works fairly well, but not as well as glow plugs would. Yet another way of doing the same thing, I suppose.

Our JD x495 diesel lawn mower has automatically controlled glow plugs. They come on as soon as you turn the key to on. Well, the x495 is meant for homeowners and so one couldn't expect those people to understand the manual key method, right??

Yep, a cot would be fine for me. Heck, don't we all have a cot in the shop for when we're told to go to the doghouse?

Later!

Stan

[robk]

Stan, you are truly an ex-spurt. My dad's plumber up in Maine used to say that an ex is a has-been and a spurt is a drip under pressure. You explain things beautifully so that even I understand. My gratitude again to you and the other guys who help me noodle my problems. It's such a great website.

[robk]

JD440ICD2006 was the first response way back when I first posted my problem. He suggested I glow the plugs with ONE battery and use the second only for starting. YESTERDAY it occurred to me that for me, this would be easy since I have quick disconnect battery clamps with big thumb wheels on the hot leads. I can just turn around to the battery mounted behind me and disconnect it while I glow the plugs. Then add the battery behind me when I go to start mode.

Stan's last post about how he keeps them on for "only a few seconds" also got me thinking. "No, you can't leave them on. Not for long, anyway. If they overheat, then they will crack inside and go bad. The usual method is the reverse turning of the key and counting off a few seconds and then trying to start it. If it goes, then you're good and if it won't, then another few seconds of plugs is in order. I like the manual method better than the automatic one the trucks use."

Stan's suggestion is NOT what the dash plate says on both my 1010's. I always follow instructions. Now I'm wondering if I cooked my plugs with a combination of too much amperage from two batteries AND following the instruction plate to the letter... and consequently cooking the glow plugs.

I'm feeling like "WE" may be onto something here... and the fix is simple. I think I have something to try anyway.

I have a Ford 7.3 diesel that won't start cold unless you cycle the ON - OFF glow plug timer several times with the ignition key. A local shop with a lot of 7.3 experience tells me the Fords have glow plug "modules" that always go bad. They say the plugs themselves are "bulletproof". I also have a JD 755 4WD tractor with a little Yanmar 3 cyl that will never start cold because the automatic plug timer goes off too soon in the cold and then will not stay on after the first cycle. You can cycle it with the on-off key ten times and it MAY start. I haven't "Jdemaris tested" the glow plugs on it to see if they are good.

[KenP]

deleted

[robk]

Thanks Ken, "Regardless of the number of batteries connected in parallel, the amperage/current through the glow plugs will not change." Yes, now I remember this point also. To your point about "leaving them on for a long time", Stan was recommending "a few SECONDS" while the instruction plate says 1 minute above 40 degrees, 2 minutes from 40 down to 10, and 3 minutes below 10. If it does start after thirty seconds of cranking, give the plugs another 30 seconds.

[Stan Disbrow]

Hi,

I usually use a 10 second or so cadence when using glow plugs, regardless of what they are on.

I had two 7.3L F350's, and on the first one I went thru glow plugs on the order of all eight in a year. Meaning that I'd have to put all new ones in come fall and then all was OK until the next fall, then they would be bad with perhaps one or two still working (but not enough to actually start the fool thing).

After the second year, I added in a cut-out switch to the coil of the glow plug relay on the module. I also replaced the entire module as it was cooked around that 'ribbon resistor'.

After that, no more fried glow plugs. Nor another half-baked module. The second replacement set went five more years, then I sold that particular truck.

When I bought the second one, I installed a cut-out switch right away. It has all eight of the original glow plugs in it still. I bought it in June of 1997, so I think I have my mileage out of this particular set.

The F350s both ran the plugs on every cold start, and left them on for several minutes. One can tell, because the voltmeter won't rise up until the module cuts them off.

I have my cut-out switch in, though, so the module comes on, but the relay won't work, so the plugs are dead. If the truck does not start on the first try, and most times it does until the temperature is below 40F, then I turn the key off, turn my switch on, and turn the key back on and wait for the start light to go out and then try to start it.

Sometimes it takes more than one cycle to get it going, of course.

Once the engine smooths out, and the smoke drops off, I turn my switch back to off, which drops the relay contact and cuts the glow plugs off.

I understand that they work it the way they do for cold emissions reasons, but I don't then take off in the truck anyway. I'm one of those that want it to idle for at least a few minutes before I go, and that's on a warm day. Colder days require more warm-up time, of course.

Now, I do not know what the heat-up characteristics of the 1010 plugs are, but a minute of hold-on before you try to start the thing seems about six times too long to me......

How long did it take for the thing to get red on the bench test? I'd say that once it was red, try to start it. It's the hot plug that ignites the cold fuel, or at least tries to ignite it. You might get a couple of those 'white smoke and then it slows to a stop' false starts, but it ought to go after a few tries.....

BTW, that's how the heater in the air intake works on the 5103. It will start and wind down in three seconds on the first try. Start and wind down after five seconds on the second try. Start and wind down after eight seconds on the third try. You get the idea, but eventually it keeps going and even stops with all that white smoke!

Oh, and you're all welcome. I like to share what I know, and even what I *think* I know!

Later!

Stan

[robk]

Stan, you may share "what you think you know" anytime with me. It's very interesting. It takes MAYBE 5 seconds for a glow plug to heat to red hot on the bench - at around 15 amps.
Your Ford experience is also informative. I'm told replacing the things on a 7.3 turbo is a heck of a job - removing the turbo, pipes, tubes, valve covers, wiring harness... they are buried in the motor. Each one is only about $11 apiece. It's the labor.