Burnt Pins
#1
01-02-2012, 10:16 AM
Burnt Pins
What causes the GP pins to burn on the UVCH, VC gaskets, and the outer VC harnesses?
2 1/2 yrs ago I put all new GPs in and had to put new harnesses, VC gaskets and UVCH on the passenger side. Now I find that there are two pins burnt on the driver's side and on on the passenger side.
I just cleaned off the burnt plastic and put it back together. I want to get to the root of the problem and make a fix for it. THESE PARTS ARE TOO EXPENSIVE AND TOO MUCH WORK TO HAVE TO FIX THIS OFTEN!!!
Why do the pins get so hot that the melt the plastic connectors? I suspect that the glowplugs get an internal short that causes the pins to get hot with too much current.
2 1/2 yrs ago I put all new GPs in and had to put new harnesses, VC gaskets and UVCH on the passenger side. Now I find that there are two pins burnt on the driver's side and on on the passenger side.
I just cleaned off the burnt plastic and put it back together. I want to get to the root of the problem and make a fix for it. THESE PARTS ARE TOO EXPENSIVE AND TOO MUCH WORK TO HAVE TO FIX THIS OFTEN!!!
Why do the pins get so hot that the melt the plastic connectors? I suspect that the glowplugs get an internal short that causes the pins to get hot with too much current.
#4
01-02-2012, 01:12 PM
#5
01-02-2012, 01:54 PM
2. No, SD uses a different connector, 1 per valve cover
Connections are usually the issue. But remember, there is approximately 32 amps of current draw per head, and that assuming each glow plug measures 1.5 ohms. How many times on here have you read "if the GP's measure 0.5 to 1.5 ohms they are OK"? At 1.5 ohms each glow plug would draw about 8 amps. At 0.5 ohms that glow plug would draw about 24 amps. You can see how easy it can get out of control.
Also, IMO bigger is not necessarily better, and I'm referring to the GPR. As far as I'm concerned the original OEM GPR, although spend-e, is superior to any aftermarket one, and it was designed to do the job. If I'm not mistaken RiffRaff has OEM GPR for a very reasonable price, about 2x cost of the after market ones.
As far as connections go they must fit very tight as 8 amps going through a connection is no big deal unless the connection is poor, that is what causes arching and heat.
#7
01-02-2012, 03:31 PM
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#8
01-02-2012, 03:37 PM
#9
01-02-2012, 04:03 PM
From My Friend Racer X
Excess resistance in the circuit is what causes it to burn the harness. Wiring is to small to handle the heat when the plug doesn't use the amps up to heat the tip. Heres a simple explanation:
Ford/Nav VC gasket/harness was redesigned with better conductors several years ago. Here's a basic way to explain it without math at all:
If the glow plug (load) were to short, the burn or weld will happen at the point the short occurs. If you use a welder it welds at the electrode (load). It won't burn up your weld cables.
So why does the harness connector melt? Excessive Resistance causes heat. A GP has little resistance or ohms. It's nearly full power that warms the tip using up power to make heat. What little power isn't used returns thru ground to battery completing the circuit. Excess resistance or poor conduction from green stuff or corrosion prevents full power from flowing to the load (glow plug). The wiring gets hot and melts because you still have a complete circuit back to battery ground, but no load to use the power up and keep the wiring cool as power flows thru it.
Now think of the welder again. What happens if you forget to put a ground clamp on the metal to be welded and touch the electrode (load) to the metal? Nothing. The circuit is not complete, so no power flows at all. No weld or short.
Best way to prevent the burned wiring is a good conductor to your GP's. I pack Di grease in all underhood connectors. The best way to keep the connection moisture free and clean is silicone dielectric.
If your harness burn't from the GP connector back, then you may have a shorted plug. Ohm it, compared to the others. If it ohms out higher than the rest it's also BAD. The extra resistance is inside the plug, not allowing full power to the tip.
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Ford/Nav VC gasket/harness was redesigned with better conductors several years ago. Here's a basic way to explain it without math at all:
If the glow plug (load) were to short, the burn or weld will happen at the point the short occurs. If you use a welder it welds at the electrode (load). It won't burn up your weld cables.
So why does the harness connector melt? Excessive Resistance causes heat. A GP has little resistance or ohms. It's nearly full power that warms the tip using up power to make heat. What little power isn't used returns thru ground to battery completing the circuit. Excess resistance or poor conduction from green stuff or corrosion prevents full power from flowing to the load (glow plug). The wiring gets hot and melts because you still have a complete circuit back to battery ground, but no load to use the power up and keep the wiring cool as power flows thru it.
Now think of the welder again. What happens if you forget to put a ground clamp on the metal to be welded and touch the electrode (load) to the metal? Nothing. The circuit is not complete, so no power flows at all. No weld or short.
Best way to prevent the burned wiring is a good conductor to your GP's. I pack Di grease in all underhood connectors. The best way to keep the connection moisture free and clean is silicone dielectric.
If your harness burn't from the GP connector back, then you may have a shorted plug. Ohm it, compared to the others. If it ohms out higher than the rest it's also BAD. The extra resistance is inside the plug, not allowing full power to the tip.
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#11
01-03-2012, 08:45 AM
#12
01-03-2012, 11:17 AM
#13
01-03-2012, 11:24 AM
If it is safe to say that the pins do not burn until the GP malfunctions causing too much current through the pins, then I would say that a properly sized fuse (maybe 10 Amp) should prevent the burnt pins except when it is caused by poor connections and arcing. Maybe packing the connections with di-electric grease will prevent burnt pins due to poor connections.
#14
01-03-2012, 03:14 PM
If it is safe to say that the pins do not burn until the GP malfunctions causing too much current through the pins, then I would say that a properly sized fuse (maybe 10 Amp) should prevent the burnt pins except when it is caused by poor connections and arcing. Maybe packing the connections with di-electric grease will prevent burnt pins due to poor connections.
#15
01-03-2012, 04:20 PM
So it sounds like in your case the pins burnt up due to a poor connection since the GP was still good.