24v hj60 glow plug current sensor exploded

[Lexjohn]

I know there are tons of glowplug issues posts but could not find anything close to what happen to me.

Truck hasn't run for 2 months, had fuel issues which I think I fixed. But while it's been sitting I've been cleaning/replacing all the wire connectors through out engine bay. I've had a glow plug issue before where the glow light turns off wait a few more seconds then here a click then watch voltage meter jump up to normal then start. Yesterday put 2 new batteries in and went to start and the glow system made a loud pop and noticed the voltage meter went right to normal no wait. Didn't start (but think it's the starter relay now that I bench tested it.) Get out of the truck and notice a little flame on the glow plug current sensor bar. Put it out and notice the sensor split inhalf and melted some of the wiring connected to it.
Below is a picture of my current sensor. I can get a new one but at 140$ I don't want to replace it then blow another one. Anyone ever had this problem or seen this happen?

 

[Freewheel]

Did you short out the sensor somehow when you were cleaning up the electrical?

Also your "issue" (with the relays clicking and voltage returning to normal a few seconds after the glow plug light turns off) is completely normal behaviour with the Superglow systems. It's a 2 stage system that first hits the busbar with just under full battery voltage, then afterglows at about ½ battery voltage. The glow light goes out when it's time to crank the engine, not when the glow cycle is finished...

 

[Lexjohn]

I barely even touched the current sensor, just cleaned up the bus bar, the connections at the 2 glow plug resistors, both relays and fusable link at the battery.

And I can't start the truck when the glow light goes out, I have to wait for the last relay to click off then I have enough voltage to crank. This might of been bad batteries. I got 2 cheap ones and have had that problem soon after. Got 2 new interstates (810cca)

 

[Freewheel]

Aha. Sounds like your starting issue could be a battery problem.

I see that you have the wiring diagram. I'd go through it and your system to make sure nothing is weird, and get a new current sensor.

Looking at that photo, is the sensor actually melted or broken? it seems to have a jagged edge on it- could it have been cracked to start with?

One thing with the Glow system is that it's a high amperage system, and any miswiring or short circuits are going to melt things quickly.

I would also make sure that your fusible links are actually fusible links, and not some previous owner putting a pice of wire in there.

(How long have you had the truck?)

 

[Lexjohn]

Thanks freewheel.

I've had the truck for 2 years, the the current sensor was fine before it broke. The wiring melted and the metal bar split in two. From what I've seen online and the diagrams in my manual it seems like I put every back together correctly. Tested the glowplug resistors and they are working and so are both relays. I'll have to check out the fusable link when I get time.

 

[Freewheel]

I just went out and looked at my sensor, and it has the wimpiest plastic grommets and insulator things that keep the sensor from electrically connecting to the engine block where it is bolted.

I would check to make sure that they are all there and that when the sensor is disconnected from both the resistor and the busbar, but bolted to the engine, it does NOT have a connection to engine ground.

If any of those plastic bits are cracked, worn through, or missing, the sensor would be connected straight to engine ground when the glow system is energized , and that could surely blow it up, especially if the fusible link is not the the correct size, or replaced by wire...

 

[Lexjohn]

gonna try and find fusible link wire today and replace it, seems to be regular wire.
And the plastic spacer/grommet was there(I dropped it and took me a day to find it between the starter and block) but maybe the wires were worn out so it grounded to the block. Just ordered a new current sensor today