2H Glow Plug Wilson Switch - Wiring Melting! (1 Viewer)

[Inventure]

I have read just about every glow plug thread I can find on here and cant seem to find anyone else that has encountered this problem.

I have an FJ45 1975 chassis, with a 88' model 2H motor. The previous owner did most of the work, however he sold it before rewiring.

I have used the FJ chassis wiring loom, and then fitted in a seperate loom to run the EDIC and Fuel Control Relay - that is done.

I also created a seperate loom to run the glow plugs using the heavy gauge wiring out of an HJ45 loom.

My problem is that I was starting the truck the other day - with a very low battery - and the extended slow cranking meant the glow plugs were left on for around a minute or so. This caused the wires to start smoking. When they eventually stopped, from what I can see the smoking was coming from the wiring going to the convertor coil in the dash.

It would seem to me that if the coil can glow red hot, then does that not mean that heat can conduct down into the wires connecting it - and cause the problem I have just had?

I would have thought that any wiring should be such that it can be left on without any risk of causing a meltdown.

So, my question is, have I wired something wrong, or is this just what would happen to any vehicle with this convertor in place if the plugs were left on for so long?

Ive attached an image of the wiring diagram I have based the glow plugs on.

 

[vwluv10338]

I will look at your attatchment when i am not on my phone but I havent had any problem with my wires. I don't have a converter on my truck however. Once my glow relay (ford starter relay) stuck and it drained my two deep cycle batteries. Overnight it killed the batteries but there was no smoke. I wouldn't think it was the heat transferring through the wires because the head acts like a big heat sink. I would think more along the lines of too small wires for the amount of amperage flowing through them.

 

[lostmarbles]

Hi Inventure

I presume by "converter coil" you mean "glow controller". (ie. - The thing that glows red/orange on your dash when you're glowing your plugs.)

If so, do you realise it carries the combined current that passes through ALL your glow plugs? So that wiring needs to be pretty beefy.

Here you can see the big black cables on mine:



Maybe your wire gauge is too small? It should be sized for 40 amps continuous (but carries way more than this for the first few seconds).



PS. You're running 8.5V plugs .... Right?

 

[Inventure]

Hi Lostmarbles

Yes, I am referring to the glow controller...

The wire gauge is roughly the size as you have pictured. It is the same wire that comes standard on an HJ45 - I dont know what the gauge is though...

When I assembled the glow controller I had to use new bolts as the originals were rusted and sheared. My bolts are shorter then yours pictured - I think the wire terminal is sitting right on top of the coil as opposed to separated by a nut as in your picture... perhaps this could be allowing more heat to conduct down the wire quicker...

In regards to the plugs, again I dont know what plugs are in the motor. I can pull them and hopefully there is a part number on them that may help identify them though. Would an incorrect plug eg. 12 or 24v perhaps try to draw more current then a 8.5v and therefore overheat the circuit? Would being a higher voltage plug mean that they draw less or more current then a lower voltage, or would it be the same?

 

[lostmarbles]

.... I think the wire terminal is sitting right on top of the coil as opposed to separated by a nut as in your picture... perhaps this could be allowing more heat to conduct down the wire quicker...

Sounds likely .. provided the overheating problem is restricted to "close to your controller".

..In regards to the plugs, again I dont know what plugs are in the motor. I can pull them and hopefully there is a part number on them that may help identify them though. Would an incorrect plug eg. 12 or 24v perhaps try to draw more current then a 8.5v and therefore overheat the circuit? Would being a higher voltage plug mean that they draw less or more current then a lower voltage, or would it be the same?

The voltage specification is normally stamped on the plugs. And lower voltage plugs draw more current (and are more likely to overheat/fail if left energised for too long).

 

[Inventure]

Sounds likely .. provided the overheating problem is restricted to "close to your controller".

It's really hard to tell where exactly the overheating problem is. I need to strip some of the insulation tape away (just taped it up and tucked it away to get ready for interior install )

It's definitely overheating just at the terminals. I'll take some photos but I could slide the ring terminal plastic protector thing back and forth because it was hot from the melting.

Otherwise, I guess I can just turn the glow plugs on and see where it smokes from again

 

[bj40green]

Hi,

Inventure, you say you have a H engine wich means a 6 cyl, which means 6x10 = 60 Amps if you're running the correct 8.5V plugs for your set up with a glow controller. The wiring in my truck with a B engine (4cyl.) is AWG8. Have a look at your wire thickness.

Good luck.

Rudi

 

[Inventure]

Hi Rudi, the engine is a 2H, not an H. But, your calculation will still be the same. Each 8.5v plug draws 10amps does it?

In terms of the wire, what does AWG8 mean? I'm almost certain the wire is heavy enough gauge wire - it was the wire that was in a HJ45 loom which should be just as heavy as needed for the 2H.

It seems to me that something other then the wire is incorrect.

 

[bj40green]

I'm not sure if I'm the right person to explain this because I'm Dutch and am used to the metric stuff (meters, centigrade, liters and so on) but living in Costa Rica where all is a big mix up (metric and imperial) I'll give it a try. AWG means American Wire Gauge and is a standard for wire sizes.
The thicker the wire the lower the number. So AWG8 is thicker then AWG10. The wiring in your house is mostly AWG10 and AWG8, so that is a kind of a reference. You can Google for; "AWG" to learn more about this subject.
Anyway, If your wire is to thin, or the contacts are corroded you can run into the problems you mentioned.

Rudi

 

[lostmarbles]

Hi,

Inventure, you say you have a H engine wich means a 6 cyl, which means 6x10 = 60 Amps if you're running the correct 8.5V plugs for your set up with a glow controller. ........
Rudi

Thanks for spotting the mistake in my reply Rudi.

(My 40 amp figure was based on a 4 cylinder engine whereas it is a 6 cylinder version we have here.)

.... it was the wire that was in a HJ45 loom which should be just as heavy as needed for the 2H.....

Some B-series and H-series engines use "superglow" where Toyota employs "low voltage plugs" and uses more complicated automatic glow-control systems to speed up starting. I think the automatic nature of these systems may have allowed the engineers to economise on "wiring gauge" because the driver no longer has direct control over "glow duration" and shouldn't normally be able to prolong it unnecessarily. (So they may have reduced the gauge on the basis that they no longer needed to size it for "continuous duty".) So I suspect "superglow" 2H wiring may be lighter than "glow controller" 2H wiring (but I'm not sure).

But anyway .... I'm doubtful any HJ45 got "superglow" so on that basis you can probably disregard what I'm saying here and stick with what you say in this quote Inventure. (I know some HJ47 models had superglow though.)

 

[bj40green]

Just a few questions to get the picture. I searched for "88 and 2H and found only HJ6# models and they are all 24V with 14V or 23V glow plugs depending of the glow circuit type.

So the questions are;
A. Is your truck 12 or 24V?
B. Do you use the the glow plugs that came with the 2H?
C. Please let us know the voltage stamped on (all of) them.
D. Did you locate where the melting took place?

If we have this info, its easier to get the picture.

Compare you wiring with the pictures below.

Look at the black / yellow stripe to the glow controller


Look at the S B and G wires and compare them to the 3 right above them. Notice the difference in thickness?

 

[kim]

Well, an 88 2H means that it isn't a Canadian market truck. Where are you located? If it is Australian market, it'd be 12v. Japanese would be 24v.

 

[Inventure]

I am in Oz. And it is 12v. I'm just downloading the iPhone app so I can upload some photos. I am thinking that maybe I have the main power connected to the wrong section of the glow plugs.

 

[Inventure]

I've attached 2 images. The first shows where I have connected the glow plug power.

The 2nd is the actual glow plug busbar. Should I be connected directly to this, or is it fine where it is connected?

You can also see the size of the wire - should be fine.

 

[lostmarbles]

There's your problem Inventure. - I should have realised before.

I've just reread your first post after looking at your pics.

A 1988 12V 2H motor would surely have been "superglow" but you've wired it all up using the "manual-glow-with-Glow-Controller loom" of a much older HJ45.

So your plugs in your 1988 2H will likely be 6V which you'll need to replace with 8.5V versions (eg. VSP PT104).

And the feed from your HJ45 glow controller should go directly to your busbar that links all six 8.5V plugs together (without any other nonsense connected between).



But something worries me.... Surely glowing with 6V plugs (instead of 8.5V) would have made your Controller glow so brightly that it risked burning out.

Then again ... perhaps you are feeding your 12V to your busbar through the step-down resistor that was used for "second stage superglow" on the 1988 2H. (This would explain why you haven't destroyed anything yet ... But it still won't work like that! ...Because that glow controller wasn't designed to operate in series with a step-down resistor and six 6 volt plugs.

 

[Inventure]

So, using the 6v plugs means I am drawing more current then an 8.5v plug would draw... Correct? If so that would hopefully explain the wire melting.

I have the power feed connected to the resistor (I think) so that would resist the current (or does it resist or convert the voltage)... Perhaps that is why the coil hasn't snapped yet... ?

Maybe my connections have created a fine line that would allow the wires enough to melt but not quite enough to snap the coil. Also, perhaps by connect the wire terminal directly on top of the coil has cause the wires to conduct some of the heat away from the coil saving it from snapping.

Can I instead of buying 8.5v plugs, remove the glow controller from the system and connect directly to the resistor only (my manual calls it a resistor) rather then the busbar? Does the resistor convert down from 12 to 6v?

 

[Inventure]

I'm still not convinced on this. Can someone help me understand volts and current and the affect each has on the other.

12v is supplied. Then the glow controller is supposed to convert this to 8.5v for the glow plugs. I then have the glow power feeding directly to the resistor (which in theory is down to 6v) and then to the 6v plugs.

So in the end all I am doing is changing 12 to 6 volts the same as the superglow system does, only I use the glow controller and the resistor. Why (or would) this increase the current more the just using the resistor as per standard superglow?

I'm starting to confuse myself now! Maybe it is as simple as the wires should not have their terminals directly to the coil.

 

[lostmarbles]

So, using the 6v plugs means I am drawing more current then an 8.5v plug would draw... Correct?

Yes. (Assuming you are hitting them with the same voltage ...9, 10, 11, 12 volts or whatever - then the 6V plugs will draw more current.)

..I have the power feed connected to the resistor (I think) so that would resist the current (or does it resist or convert the voltage)... Perhaps that is why the coil hasn't snapped yet... ? ....

Yes I think the dropping resistor may have stopped the 6V plugs from destroying your glow controller. (Dropping the voltage across something has the effect of reducing the current flow within it.) In other words, I suspect you have been applying "second stage superglow" (also called "afterglow"). BUT ... since you are feeding the juice to the "dropping resistor" via a Glow Controller (which drops the voltage further and in the same way the resistor does) .... I think your second stage won't be glowing your plugs properly due to insufficient current flow (cause by insufficient "potential/voltage difference" across each "load component" in the circuit).

Without having those two resistors (the Glow Controller and Dropping Resistor) in series ... Yes. I think you would have blown your Glow Controller by running those 6V plugs. (Assuming they are indeed 6V plugs ... And it would pay for you to confirm this by extracting them and checking.)

...Maybe my connections have created a fine line that would allow the wires enough to melt but not quite enough to snap the coil. Also, perhaps by connect the wire terminal directly on top of the coil has cause the wires to conduct some of the heat away from the coil saving it from snapping. ...

Your overheating wiring suggests to me that you've had excessive currents that should have destroyed your Glow Controller too. So I'm likewise puzzled. (Which makes me suspect I still may not be diagnosing your situation correctly.)

....Can I instead of buying 8.5v plugs, remove the glow controller from the system and connect directly to the resistor only (my manual calls it a resistor) rather then the busbar? Does the resistor convert down from 12 to 6v?

Yes and Yes. That should give you a system that works, but with no visual indication of when you should crank. (Just wait 20 or 30 seconds by counting in your head I guess).

(But personally I LOVE glow controllers and dumping energy via the "dropping resistor" is rather a waste compared to "seeing a visual indication in front of you" for when you should start cranking.)

Have a good read of this thread if you haven't already (to check the various wiring methods):

https://forum.ih8mud.com/diesel-tec...gs-should-i-running-b-2b-3b-h-2h-diesels.html

....12v is supplied. Then the glow controller is supposed to convert this to 8.5v for the glow plugs.

Quite right ....provided you're running 8.5V plugs and have the big lead from the glow controller connected directly to the glow plug busbar (with nothing else inbetween).

... I then have the glow power feeding directly to the resistor (which in theory is down to 6v) and then to the 6v plugs.

Yes - providing you remove the Glow Controller from its upstream position! (Upstream, the Glow Controller will act as a Series Resistor and inhibit current flow.)

Hope all this helps.

 

[bj40green]

I'm still not convinced on this. Can someone help me understand volts and current and the affect each has on the other.

12v is supplied. Then the glow controller is supposed to convert this to 8.5v for the glow plugs. I then have the glow power feeding directly to the resistor (which in theory is down to 6v) and then to the 6v plugs.

So in the end all I am doing is changing 12 to 6 volts the same as the superglow system does, only I use the glow controller and the resistor. Why (or would) this increase the current more the just using the resistor as per standard superglow?

I'm starting to confuse myself now! Maybe it is as simple as the wires should not have their terminals directly to the coil.

OK. I'll try to shine some light in the world of glow systems.
You are mixing up 3 different glow systems. You are creating a Wilson switch set up, with a controller from a Manual glow system and using the resistors and 6 Volt glow plugs of a Super glow system.
That's not gonna work. To explain a little bit I made a drawing for a Wilson and a Manual glow system.
You can decide for a glow controller or not. If you don't then you have no idea what's happening and you have to rely on counting the seconds and your experience. You need 10.5 V plugs for this.
If you decide for the controller then you have a visible indication of what is happening under the hood, but that means you have to replace the plugs for 8.5 V type.
The glow controller is not a converter. It's a resistor getting so hot it starts to glow. By doing that it needs +/- 3.5 Volt so add the 8.5 Volt glow plugs and you have your 12V system.



To connect you glow plugs directly it should look like the strip in the picture or you can make one yourself like I did for a special meassurement job.



Good luck.

Rudi

 

[fjbj40]

I will chime in here. I converted my bj40 (24 volt) over to 12 volt. I installed the glow plugs out of a bj60, superglow system so 8.5 volt plugs. I left the 24 volt glow controller in place and hit the glow switch.....smoke and I melted the coiled wire in the glow controller!

I figured 12 volt batteries, 8.5 volt plugs it should have worked fine, but it melted the coiled wire in the controller? Why did it do that?

I have since temporarily removed the controller and just bolted the 2 wires together and the truck starts perfectly after approx 8 seconds.

I think I will just wire a lamp between the 2 wires and be done with it.

Daryl