SS diesel glow plugs

[CUCVFAN]

RE: 12 vs 24?

So, I thought that the module used the temperature switch to determine how long to energize the plugs and a timer to turn on the wait light? How does measuring the voltage at the relay help it determine how long to energize the plugs? I see that the wiring diagram calls the orange wire the "voltage monitor", but we know from other discussions that the TM's can be a little misleading. I still haven't looked at the card closely, but I did look at the diagram again and I'm still not clear on this.

 

[CCATLETT1984]

RE: 12 vs 24?

the module reads the voltage draw of the plugs, as they heat they draw less voltage. Its the way the controller knows the GP's are heating. the voltage sense transistor on the card is what will be sacrificed if you hook it up to 24volts, thats what happens when the resistor fails and lets 24v through to the controller and plugs.

you would need to use a 24v controller and odds are, would have to change the temp switch too.

 

[CUCVFAN]

RE: 12 vs 24?

Forgive me, as it's been 15 years since I've done any actual circuit design, but since you used the word "draw", I assume we are actually talking current, not voltage? The voltage potential across the output of the relay and ground (which is all the controller knows about) is still 12V, even when the plugs are hot. If we are talking about the current flowing through the plugs going to zero (or whatever), then since the controller is not grounding through the glow plugs, I don't understand it can use this to determine the current flow through them. Plus, why would the module have a habit of burning out plugs if it cycled too many times?

 

[CCATLETT1984]

RE: 12 vs 24?

yeah, soory about using the wrong term, could confuse people (as if I don't confuse myself enough as it is! )

It is has the same source as the GP's
since they both go through the restistor and the resistor cuts back the voltage as it heats up, there would be a noticable change at the controller, forgive me if I am not explaining this correctly.

 

[CUCVFAN]

RE: 12 vs 24?

I understand they have the same source, but I don't see how that helps. If it is sensing the voltage at the source (after the resistor) and using that voltage, then it can only determine how hot the resistor bank has actually gotten, right? I guess it could use this value to determine how long to leave the plugs on, but the two just seem too disconnected.
Plus, I can't see this working for one main reason: It still operates the same if you pull the power for the GP's off the 12V junction block, instead of the resistor on the firewall. In fact, I've heard lots of people recommend this change.

 

[ida34]

RE: 12 vs 24?

If pull 12 from the junction block you will not be able to use slave cables to start it. I can't comment on the rest.

 

[CUCVFAN]

RE: 12 vs 24?

True, if the batteries are stone dead, that is a drawback. I was just saying that if the card still works properly (under normal conditions) when that mod is performed, then I don't think the firewall resistor figures into what it's doing with the voltage.

 

[Blake]

glow plugs

I just tried to bypass the resistor and use 24 volt ss diesel plugs. The plugs would come on and then go back off. They would not stay on long enough for them to heat up and start on a cold morning. I had a new controller in place and it would not work. Put the regular plugs back in and a takeout resistor, started fine.

 

[CUCVFAN]

RE: glow plugs

This reminds me of the other thought I had about voltage sensing. I thought maybe the card prevents the plugs from cycling if the voltage is too high? That would prevent them from burning out. But, it seems to me that a few folks have said that the card burns out with this sort of situation. I guess that's still a fail-safe of some sort, but not was I was thinking.

Was everything else in your setup stock when you tried the 24V plugs? Did it burn out the card? Did you try to leave the small orange wire on the resistor, so it only saw 12V?

 

[85-m1028]

when I first got my truck, it had the ac delco 13G plugs and only one was still good. I noticed that the resister was bypassed and the relay was connected to the 12v block? After tracking down a new set of 13G plugs and reconnecting the resister it only took about a week to kill those plugs.

I did notice that as the week progressed the wait light duration would shorten on cold starts. First it was 8sec then about 6sec enventualy to about 3sec as most of the plugs were dead!

I think it does measure the load somehow??

After that set of 13G's I tried the wellman plugs, checked the resistor on the firewall it showed 3ohms and that new set lasted about 2 weeks? The wellman plugs did the same thing "wait light duration got shorter and shorter"

I bought another set of wellman plugs checked all the connections and bypassed the resister to the 12v block once again, guess what same results!

In hind sight crimping on a new set of 1/4" female tang connectors and throwing in a set of 60G's would have been the cheapest way to go. This would be course I would recomend for anyone who wants to try and keep the stock mil system!

 

[CUCVFAN]

So, you no longer have the problem with the 60G's? It is now hooked up with the resistor and working fine? And nothing else changed?

 

[85-m1028]

So, you no longer have the problem with the 60G's? It is now hooked up with the resistor and working fine? And nothing else changed?

No I'm the guy who bucked the system and decided 12v conversion was better for my use. "see civy glow plug controler conversion"

Had I known that you could just change the tang connectors and used delco 60g plugs, I may have still had the mil system today?? I just thought that the mil system reqiured the special plugs! Once I figured out how to wire the civy controler and make it work, the reasoning to do out weighed the not to do!

I don't even run the 60g's I run the autolite 1110 plugs. After doing the conversion I read about a lot of people who had similar probs, ran the 60g's and solved their problem.

 

[bassplayer88]

RE: 12 vs 24?

The connection from the Pos Term ( TM-9-2320-289-20) F-1 to the resistor bank is 24v , resistor converts 24v to 12v, out resistor bank to glow plug controller is 12v.. 12v to the solenoid closes circuit 12v to the glow plugs.. OK sounds good BUT, the resistor still allow +12v at the initial closing of the glow plug solenoid , causing a spike in voltage to the plugs .. The Glow Plug Module is pulling from 12v see figure F-7.. Prior to changing my glow plugs out , but unaware to me, M1009 had Wellman G070's at 24/12 volt .. I replaced them with New Wellman G070's on a manual glow plug controller , and 12v conversion .. No issues at all...

 

[rizzo]

RE: 12 vs 24?

this is confusing to me. I'm getting most of it, but need some help on the following:

I bought new "military" GP's from SS Diesel and now they don't work.

are the G070's the ones to buy? do they have the thing that will protect them from overheating?

is the reason civy plugs don't work because of a voltage spike caused by using a resistor?

 

[rizzo]

RE: 12 vs 24?

response from Walt at SS

"Hi Kevin,

It should be an 070 on the barrel portion, not the hex. Make sure of that.

You have a bad controller. The way your system should work is hit the plugs with 24 volt for a second or two, then switch over to 12 volts.
If it stays on 24 volts too long they will smoke.
Yes they have over-temp protection, but NOT over-voltage protection."

 

[rizzo]

RE: 12 vs 24?

when i took the old plugs out of my truck they were all AC 13g

after I installed the new plugs from SS Diesel they stopped working after a week so I took 6 plugs out of my truck and 1 was labeled AC 11g the rest were wellman 070g. the last two i can't get out by hand. I am assuming the tip is bulbus and won't fit out the hole.

After I installed the new plugs last week I was manually jumping the selonoid to start the engine. The longest I held the power on was 20 seconds. any comments on the manual jumping procedure?

 

[CUCVFAN]

RE: 12 vs 24?

The G070's are the CUCV plugs. Were the old plugs (13G's) not working? It sounds like you've got 2 swelled plugs. I'd be a more than a little pissed at receiving 1 (or more) AC 11G's when I ordered G070's!

The stock system does not switch from 24V to 12V after "a second or two". Nothing about the system is designed to do this. It gets power for the plugs from the resistor, which should be providing approximately 12V. Check your voltage at the output of the resistor to make sure it's not too high. I have never tested it during operation, but I do not think there's a spike to 24V before leveling off when the plugs are active. If there is a spike, I'd bet it's VERY short nad not 1 or 2 seconds in duration. You'd probably have trouble measuring it.

Manually operating the G070's for 20 seconds will not harm them unless the voltage is too high as you were already told.

 

[ARMYMAN30YearsPlus]

RE: 12 vs 24?

I just put the SS GP's in my 6.5 TD Suburban and for the first time since I have owned it got the #6 one in which is behind the exhaust down tube. Forget about the #8 it is lost in the firewall engine breathing space. Anyway the Suburban finally starts great in cold weather with just one GP cycle. I have put in several other brands and they did not cut the mustard. I highly recommend them as Mike did to me. I plan on putting them in the M1009 as soon as payday rolls around.

 

[rizzo]

Re: RE: 12 vs 24?

Manually operating the G070's for 20 seconds will not harm them unless the voltage is too high as you were already told.

what if you left them on for an hour while driving the truck? with the temp protection, they should be ok right? I wonder if my resister is bad and letting more than 12 volts through?

if some of the plugs are bad will that cause the others to fail?

 

[CUCVFAN]

RE: Re: RE: 12 vs 24?

Check the output of the resistor. An hour will not hurt them either, but while driving the truck might be a little different. Not only are you stressing them with temperature, but they are also being subjected to continual high combusiton pressures, fuel spray and engine temperature. Not sure if this would cause premature failure, but I would not doubt it could contribute.

It is often said that as plugs go bad, the others will fail faster. The voltage does not increase, and the current a plug can draw is what it is, so neither of those should affect it. I'm sure someone will chime in with an explanation. My theory is that they get cycled more and more trying to get the truck started and this shortens their life. Although, you should not have this problem with the self-regulating type....