CK5
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Bad lot of AC60g glow plugs
- Thread starter K5wrench
- Start date
No. All the civilian trucks ran one alternator with one pulley. And the military trucks ran 24 volts into the GP circuit (as you're aware). The alternators regulate different battery circuits independently, so they do not influence each other directly. It's not like the Ford system with parallel alternators.
And we both know that if GM had really been concerned about glow plug longevity....they would have used a voltage regulator instead of a resister bank.
I do not know what GM did with their dual alternator setup. I'd point you to @AgDieseler for that answer. He's running dual alternators, and I think he copied the stock 1997ish belt setup.
Of course...if you're cycling out counterfeit glow plugs your failure rate should drop either way.
I came really close to installing a second alternator with my engine rebuild (still in progress). I wound up shelving the idea because I didn't have the right brackets to make it fit, and it was time to get the engine stabbed into the truck. I would run it back to my camper battery so the two systems could charge independently. As it is the plan is to use an isolation switch and just manually connect the rear battery when the alternator is spinning.
If you want to sell the bracketry I may be interested...
Yeah, when I got my M1009, the original owner had put the gp's onto one batt.
I foolishly bought a 30 year old resistor bank and installed it to put things back stock.
The resistor bank was fried.
Or rather, it tested good, but fried and short circuited to ground shortly after installation.
Killed all eight original glow plugs and set me on the journey of 12 volt conversion.
But I had to be a smart guy..
No.
I could'nt just do the Roscommon conversion step by step.
I wanted to leave that second alternator in there.
Typical for me.
I will evemtually push everything in every direction possible until i find failure.
For now, i'll run one alt and collect data.
Observe glow plug resistance.
See if any of the same batch die.
I foolishly bought a 30 year old resistor bank and installed it to put things back stock.
The resistor bank was fried.
Or rather, it tested good, but fried and short circuited to ground shortly after installation.
Killed all eight original glow plugs and set me on the journey of 12 volt conversion.
But I had to be a smart guy..
No.
I could'nt just do the Roscommon conversion step by step.
I wanted to leave that second alternator in there.
Typical for me.
I will evemtually push everything in every direction possible until i find failure.
For now, i'll run one alt and collect data.
Observe glow plug resistance.
See if any of the same batch die.
You know what is most kooky about this?
The glow plugs are rated at 10.5 volts.
But they damn well get at least 11 volts during glow with healty batteries and 13.2 during after glow.
The entire glow system surviveability was designed based on voltage drop during startup.
Otherwise the glow plugs would be rated 13.2 volts.
The GM glow plug system seems aweful similar to the Blazer rear hatch window system.
They did so many things right.. but what they got wrong...
The glow plugs are rated at 10.5 volts.
But they damn well get at least 11 volts during glow with healty batteries and 13.2 during after glow.
The entire glow system surviveability was designed based on voltage drop during startup.
Otherwise the glow plugs would be rated 13.2 volts.
The GM glow plug system seems aweful similar to the Blazer rear hatch window system.
They did so many things right.. but what they got wrong...
They are rated at 10.5v, I believe that is the minimum to glow.
Doesn't mean they can't take more or they are meant to run on 10.5v all the time
And yet, every glow plug controller for the 6.2/6.5 has an afterglow feature that runs the gp's after the engine is running and while the alternator is supplying the system 13.2 to 14.8 volts.
Hmm.
Yes, they will glow at 13.8v better than at 11v, but it's usually very short time.
I remember 2, 3 seconds each afterglow?
I have two different gp cards.
Both turn off the wait light before glow time is over, based on measuring the gp relay.
Maybe i should wait until the voltmeter says glow is over i stead of light.
They should have wired the wait light to the gp relay.
Both turn off the wait light before glow time is over, based on measuring the gp relay.
Maybe i should wait until the voltmeter says glow is over i stead of light.
They should have wired the wait light to the gp relay.
You'll notice they kept tweaking it through the years, looking for a happier solution.
Remember...the original 9G plugs were only rated for a few seconds before burning out. Hence the 2-second glow period on the old controllers. A 60G isn't a good fit for an old controller because it heats slowly. So you'll be waiting for a while.
Agreed. But my trucks don't have wait lights, they have glow plug lights. It makes sense that the GP light shows when the GPs are burning, eh?
"Wait" is a lot more ambiguous, I'm not sure why they changed it.
What resistance did you measure when you first installed it? Shorting to ground wouldn't have burned up plugs, it must have shorted across the terminals. Getting too close to zero ohms.
For what it's worth, mine now measures 0.0 ohms. But I burned up 7 glow plugs within a couple of cranks. So mine probably isn't a good baseline.
I don't miss it.
Once when I bought 8 AC 60G glow plugs at Autozone I noticed one wasn't an AC,despite being in an AC box--it was stamped "Wellman" brand,and I did not want one odd ball in the engine,so I brought it back and told the counterman I want all 8 to "match" and be the same brand--he gave me 3 AC's in exchange and told me "sorry for the inconvenience"..so it is possible you may not have gotten "real" AC's,but some cheap generic substitute..
I will not use Champion glow plugs either,they truly suck,they fail rapidly and swell up so bad you'll be lucky to remove them later when they do..and I've already stated how I feel about Autolite 1110's ..
Right now my truck has at least one 9G glow plug,after I discovered at least one dead 60g during the worst of last winters weather,that was all I had,so I put them in just to get by.
I had two complete sets of 9G's given to me "good used" condition,so I figured I may as well use those,I didn't feel like wasting $10 each on more 60g AC's..
..I'm hoping they wont swell up,but if they do--oh well...
I'm to the point I'm ready to go back to a gas engine or a different truck..I don't hate the 6.2 but I'm not a big fan of them either..don't like paying over $3 a gallon for diesel either..
Regarding the dual alternators--they shouldn't overpower the glow plugs if they were wired up correctly,one of the wires on the 2 prong plug is a "sensing" wire that reads the voltage,and tells the alternator regulator how much amps to put out--that should only increase during a heavy load,or when they are replenishing what you drained from the batteries right after cranking it over for a minute or so,and the regulator should maintain it well under the 14.5 volt maximum..
The glow plugs are rated at 10.5 volts to make them warm up quicker and drain less amps than if they were rated for higher voltages..
I will not use Champion glow plugs either,they truly suck,they fail rapidly and swell up so bad you'll be lucky to remove them later when they do..and I've already stated how I feel about Autolite 1110's ..
Right now my truck has at least one 9G glow plug,after I discovered at least one dead 60g during the worst of last winters weather,that was all I had,so I put them in just to get by.
I had two complete sets of 9G's given to me "good used" condition,so I figured I may as well use those,I didn't feel like wasting $10 each on more 60g AC's..
..I'm hoping they wont swell up,but if they do--oh well...
I'm to the point I'm ready to go back to a gas engine or a different truck..I don't hate the 6.2 but I'm not a big fan of them either..don't like paying over $3 a gallon for diesel either..
Regarding the dual alternators--they shouldn't overpower the glow plugs if they were wired up correctly,one of the wires on the 2 prong plug is a "sensing" wire that reads the voltage,and tells the alternator regulator how much amps to put out--that should only increase during a heavy load,or when they are replenishing what you drained from the batteries right after cranking it over for a minute or so,and the regulator should maintain it well under the 14.5 volt maximum..
The glow plugs are rated at 10.5 volts to make them warm up quicker and drain less amps than if they were rated for higher voltages..
I'm sure you already know this, but pairing a quick-heating plug with slow-heating plugs means either the fast one will burn out (if you run long cycles) or the slow ones won't be getting very hot (if you run short ones).
At least on this 86 M1009, the glow plug card controls the wait light seperately from supplying ground to the glow plug solenoid.
I bought a brand new glow plug card (not cheap) and it operates the same way.
So you turn the key, wait light comes on, glow plugs go (based on voltmeter reading).
After a period of 8 to 15 seconds (depending on temp) the wait light goes off but the glow plugs still go for another 5 seconds.
I replaced the gp solenoid too.
Does the same thing.
I think I'd rather have the wait light wired to tell me when the glow plugs are on.
Of course i can just ignore the light and watch the voltmeter gauge and easily see when they are on or off.
Runs great so far.
I do miss the second alternator because of the additional belt driving the ps pump.
Yesterday i went out and broke open some snow drifts on the trails so we have some place to take guests in the atv's.
A couple of times my ps squealed.
Got a new belt on there and tight.
Never made a peep with the second alt and extra belt.
I am rebuilding that extra 27si alt.
Just waiting on a part.
May put it back in just for the extra belt.
I bought a brand new glow plug card (not cheap) and it operates the same way.
So you turn the key, wait light comes on, glow plugs go (based on voltmeter reading).
After a period of 8 to 15 seconds (depending on temp) the wait light goes off but the glow plugs still go for another 5 seconds.
I replaced the gp solenoid too.
Does the same thing.
I think I'd rather have the wait light wired to tell me when the glow plugs are on.
Of course i can just ignore the light and watch the voltmeter gauge and easily see when they are on or off.
Runs great so far.
I do miss the second alternator because of the additional belt driving the ps pump.
Yesterday i went out and broke open some snow drifts on the trails so we have some place to take guests in the atv's.
A couple of times my ps squealed.
Got a new belt on there and tight.
Never made a peep with the second alt and extra belt.
I am rebuilding that extra 27si alt.
Just waiting on a part.
May put it back in just for the extra belt.
