Removing glow plugs on YD485 4 cylinder

   / Removing glow plugs on YD485 4 cylinder #1  
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meexiles

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Apr 29, 2007
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I am blowing the 30 amp fuse when the key is in the "heater" position. I have removed the copper bar linking all of the glow plugs together. When doing an in-place test, the resistance is about 0.2 ohms across each plug. So, I am trying to remove the glow plugs in order to bench test each one. But I am having trouble fitting my socket down over the glow plug as it seems to be too close to the valve cover/head of the engine.

Am I doing something wrong, or must the head/valve cover be replaced in order to pull the glow plugs?

Thanks!
 
   / Removing glow plugs on YD485 4 cylinder #2  
I don't know how to remove the glow plugs, but I'll offer the following thought:

With four plugs and a 30 Amp fuse, each plug should pull a maximum of 7.5 Amps. Volts=Amps times resistance, so the resistance of each plug should be no lower than 1.6 Ohms (lower resistance means more Amps). So if they're all giving you 0.2 Ohms either they're all bad or your reading is off. Most ohmmeters are not accurate to that low a reading, the more accurate test would be to apply 12V to each and measure the current, if you have an ammeter that can safely read that high. A crude test would be to apply voltage through a 10A fuse and see if it blows.

I would also look at the keyswitch, it may be shorting to ground. I don't think they're really meant to carry 30A and using them directly to the glow plugs is something of a hack.
 
   / Removing glow plugs on YD485 4 cylinder #3  
I have to side with QUICKSAND, I think your plugs are OK from your readings.
\My take would be that a plug would be either OK or blown.
You did the proper procedure to test.
\One suggestion might be to replace the wire lead to the plugs 'bar' with a heavier gauge wire that is carefully crimped or soldered as well as making sure all contacts are 'metal to metal' (including grounding points).
Bad grounds create resistance which in turn increase amperage to get same wattage causing fuses to blow.

Key switch is also a good point.
I personally like to squirt WD40 into the key slot from time to time to clean and re dissolve the lubricant they use inside as it tends to dry and cake up making for poor contacts. (having dissected a few switches I came to this conclusion)
Contact cleaner works also but it evaporates rapidly while WD also softens the lubricant to like new without any corrosive effects.
 
   / Removing glow plugs on YD485 4 cylinder
  • Thread Starter
#4  
PILOON said:
I have to side with QUICKSAND, I think your plugs are OK from your readings.
\My take would be that a plug would be either OK or blown.
You did the proper procedure to test.
\One suggestion might be to replace the wire lead to the plugs 'bar' with a heavier gauge wire that is carefully crimped or soldered as well as making sure all contacts are 'metal to metal' (including grounding points).
Bad grounds create resistance which in turn increase amperage to get same wattage causing fuses to blow.

Key switch is also a good point.
I personally like to squirt WD40 into the key slot from time to time to clean and re dissolve the lubricant they use inside as it tends to dry and cake up making for poor contacts. (having dissected a few switches I came to this conclusion)
Contact cleaner works also but it evaporates rapidly while WD also softens the lubricant to like new without any corrosive effects.
Click to expand...

So I measured the voltage from the wire feeding the bar to ground when the switch is in the HEATER position, and it shows 12.24V which doesn't seem too bad to me. Checking the current draw under load seems kind of pointless, since I already know I am exceeding 30A as the fuse blows after being in the HEATER position for more than about 2 seconds.

I'll try squirting some WD40 in the key slot; that is easy and quick to do.

Regarding the ignition switch issue, does anyone know of a kit or design that one could follow to do the ignition switch "bypass" to eliminate the 30A going through the ignition switch?

Thanks for your help!
 
   / Removing glow plugs on YD485 4 cylinder #5  
   / Removing glow plugs on YD485 4 cylinder
  • Thread Starter
#6  
   / Removing glow plugs on YD485 4 cylinder #7  
meexiles said:
How would one wire this up on the respective circuits? I'd probably go ahead and buy two and upgrade the solenoid circuit at the same time as I did the glow plug circuit.
Click to expand...

It's very simple and straightforward, plus they come with generic instructions. You will have to add some new heavier gauge wire and a couple of in-line fuses or circuit breakers.
 
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