AC60G Glow Plug Failure

[motormayhem]

I see the AC60Gs are recommend for resistor bypassed trucks, but from some quick searching I can't find why they are not recommended for non-bypassed trucks?

I put them in my stock CUCV a little while back (maybe 200 starts with 100 being below 50F outside). However, when I went to pull the truck out of storage over the holidays it seems all the glow plugs are failed (infinite resistance). I'm assuming I had a cascade failure and cooked the remaining ones quickly, but I'm curious what caused it.

I plan to do some checking of voltages, but the set before (not sure what model) lasted 10+ years of more regular use and only had 1-2 failed units when I swapped them out. My two thoughts right now are either the AC60Gs were the issue or the coolant temp sensor came loose and caused them to cycle to death. The coolant temp connector has just about turned to dust so I may have a bad connection there, however, I didn't notice them cycling while driving.

 

[WWRD99]

I see the AC60Gs are recommend for resistor bypassed trucks, but from some quick searching I can't find why they are not recommended for non-bypassed trucks?

I put them in my stock CUCV a little while back (maybe 200 starts with 100 being below 50F outside). However, when I went to pull the truck out of storage over the holidays it seems all the glow plugs are failed (infinite resistance). I'm assuming I had a cascade failure and cooked the remaining ones quickly, but I'm curious what caused it.

I plan to do some checking of voltages, but the set before (not sure what model) lasted 10+ years of more regular use and only had 1-2 failed units when I swapped them out. My two thoughts right now are either the AC60Gs were the issue or the coolant temp sensor came loose and caused them to cycle to death. The coolant temp connector has just about turned to dust so I may have a bad connection there, however, I didn't notice them cycling while driving.

If that coolant temp sensor gets disconnected the glows do the 3 30 second post running cycles every time it starts. I run 60g in mine. Mostly because I can get them at the local parts store easily. The 13g is the stock one if I remember right it has the thinner blade connectors. I haven't looked to see what the difference is between the 2 otherwise. I don't know why a 60g wouldn't work with the resistor still wired in. I'd check the voltage for the output to the glows when the solenoid is turned on. Could be the resistor isn't working 100% and you're getting more than 12 volts to them.

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[Tinstar]

My M1008A1 is factory stock.
Resistor system all original and works great.
I run the AC60Gs
Have been for almost 9 years and have had only 1 glow plug go bad after about 5 years. Part itself failed and not due to resistor failure.
I did replace them all since their inexpensive enough.

Only Difference between the two (13g/60g) that I'm aware, is the size of the spade connector.
Due to the design of the resistor system, when one glow fails, the rest will quickly fail.

Truck starts no sweat in cold weather including below -0.
My coldest start is -15 below a few years ago and fired right up.

Guys here run both part numbers in both configurations, with or without resistor.

The big advantage to the 60Gs is they don't swell over time and make it difficult to remove.
I have no experience with the 13Gs, but the forum threads show it's also a good plug.

 

[motormayhem]

Ah ok, good to know. I put the AC60Gs in because I didn't want to deal with the swelling and don't need them to heat fast as I generally live in a warm area.

So that coolant connector won't cause the GPs to cycle when the truck is warm/running? Just will cause the GPs to run a max heating cycle on every startup? The connector is toast and the wires are exposed so I suspect a bad connection there is very likely, but that is easy to fix.

Given they all failed so fast I wasn't sure if it was because the control card didn't worth with them or because of something else. Sounds like the best course of action is to order another set of 60Gs, a coolant sensor + connector, and hook it all back up. Once I have that done as long as I'm dropping down to ~12V out of the resistor bank things should work correctly right?

 

[WWRD99]

Ah ok, good to know. I put the AC60Gs in because I didn't want to deal with the swelling and don't need them to heat fast as I generally live in a warm area.

So that coolant connector won't cause the GPs to cycle when the truck is warm/running? Just will cause the GPs to run a max heating cycle on every startup? The connector is toast and the wires are exposed so I suspect a bad connection there is very likely, but that is easy to fix.

Given they all failed so fast I wasn't sure if it was because the control card didn't worth with them or because of something else. Sounds like the best course of action is to order another set of 60Gs, a coolant sensor + connector, and hook it all back up. Once I have that done as long as I'm dropping down to ~12V out of the resistor bank things should work correctly right?

Definitely fix the coolant temp wires. If it has the 2 wire connector I'd just replace the wiring. I've found the new sensors aren't exactly the right resistance to make the card do the correct glow times vs temp. Check the glow times with a volt meter on the output of the glow relay to make sure you're not over 12 volts when it's turned on. I'd be checking the output several times over a few days just to make sure the resistor is working right and not staying on to long for the temp. It could be that the volts are to high and the glows were on too long. Hate to see the new glows get burned up quick.

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[Tinstar]

As already stated, hook up the coolant sensor.
I replaced mine when I first bought truck.
I think the new style is one wire?
(Not sure, been a minute or two)

Glow plugs still cycle as intended and do the afterglow once or twice after it’s started, if it’s really cold outside.

Yes.
12v is fine for the plugs.