Glow plugs, and solenoid problem

[2deuce]

My sons M1009 has an issue of the glow plug solenoid not turning off when it should after startup.
1)First the truck would not start unless you gave the solenoid a whack. That told me it probably wasn't making good contact inside and we needed a new one. Got a cheap one off ebay and it didn't work out of the box. They replaced it with another that does work but....
2)Usually when cold we get the after glow a couple of times as the truck warms up. As the solenoid turns off for the last time it flutters making a buzz type sound. I'm thinking that the voltage supply to the solenoid has lowered to a point that the solenoid doesn't know whether to turn off or on and does both very fast for about a second. While I don't think this is normal in any way, I wondering if power to the solenoid is supposed to drop slowly/gradually or turn off positively, and on the same way, because it appears that this is not happening.
3) Today the glow plugs stayed on a long time after up, probably close to a minute. Then they started to turn off and on many times becoming more rapid until I again got the flutter/buzz and then they were off and stayed off.

This truck has the resistor bypassed and the fast idle does not work, making it already harder to start than it should.

I don't understand the action of the glow plug card and the temp sensor and how power is sent and regulated to the solenoid. I'm thinking of going to a manual setup, but I'd like to understand this system better. If someone can explain what is going on here, that would help in my understanding.

Thanks

 

[cpf240]

The buzz, or flutter, is not uncommon. I'd suggest looking at the glow plug troubleshooting section in the -20TM. My guess would be that the temp sensor is going bad.

 

[2deuce]

Yeah, I thought that before, and put in a new one a couple of years back. The problem, if I remember right was the temp sensor read hot so the glow plugs would not come on. Now they stay on too long. I'll read that trouble shooting section again, but it doesn't explain how the system works, like how the GP solenoid is turned off. I think the card detects how long the glow plugs are on and the temp sensor lets the card know when the engine is warm enough, but is there a switch in the card that turns everything off or what. I've seen burnt out cards too and don't know if there is a specific cause. I don't like the glow plugs staying on too long and getting too hot either. The more I think about it the more I want a manual setup.

 

[Tinstar]

Stay away from cheap parts.
Most of the time they cause more issues than not.

Get ACDelco 60g glow plugs.
They are self-limiting and recommended for the CUCVs.

The temp sensor on passenger side low is for the cold advance.
The GP temp sensor on drivers side high is to tell the glow plugs if their needed or not depending on engine temperature.
Engine cold, yes turn on.
Engine warm or hot, no your not needed right now.
The two sensors are not linked. They each perform separate functions.

The GP card is to link everything GP related together.
It determines when the wait light comes on and the duration of the GP heat up.
Once engine starts, it determines if an afterglow is needed and how many.
Its the brains of the system.

I would replace the GP temp sensor.
It's much cheaper than the cold advance sensor, which sounds like needs replaced also.
I would also replace the cheap solenoid with a quality part.
Of course check all connections again.


I'm not sure how bypassing the resistor will affect it.
Mine are all stock.
Me personally..., I would put it back stock.
I know a lot of guys have bypassed the resistor and have done a manual setup with success. It works for them.
Once you understand the stock system, it's very easy to maintain and troubleshoot.
You will also be able for full use of the TMs and more people here on SS to help.
Once you start hacking (figure of speech) then your kinda on your own.

The stock system works very well when maintained properly.
Mine started like a champ when it was 3 degrees outside a few days ago.
I have yet to use the block heater.

 

[2deuce]

I have a tendency to look at electricity in a wire like water in a pipe where amps is the water and volts is the pressure. So it is hard for me to wrap my head around the thought of the solenoid turning off and on a few hundred times in the blink of an eye to flutter and buzz. Then complicate that the next time when it turns off with a clunk of click. I've taken GP solenoids apart to see why they fail. I don't know the reason for the long duration of the glow plugs, but it sounds like the sensor or the card. As far as the resistor goes I don't think it has an effect on glow plug duration, it's removal only saves your glow plugs from the cascade fail event of all the plugs. Thanks

 

[dmetalmiki]

IF you go manual..be careful, Some units do run intermittently after initial start up, BUT at reduced power. if you bypass the resister the glow plugs receive the 'full whack' and oblige by promptly burning out.
The previous post advice on the 'limiting' good quality glow plugs alleviates this. And yes, stock is best.

 

[Grega]

My glow plugs started the fuzz/flutter noise after I did the resister bypass, no manual button, usually 5 to 10 seconds after I start the truck, but still works good.

 

[2deuce]

what I mean when I say bypass the resistor is bypass it with 12 volts not 24 volts, by only using 12 volts there is no "full whack" ever. This protects your glow plugs from burning out because the resistor will let your 12 volt GP's receive over 12 volts in many circumstances, and when one burns out the rest soon follow. I don't understand why anyone would want that resistor connected unless you have a truck starting without any issues and want to leave well enough alone.

 

[cucvrus]

I don't understand why anyone would want that resistor connected unless you have a truck starting without any issues and want to leave well enough alone.

I have all 7 of my CUCV's wired as original and use the original 13G glow plugs. I never had any problems. I turn the key wait and it starts right up and I wait for the system to cycle the glow plugs 2 - 3 times aafter it starts. When the cycling is complete I put it in drive and away I go. When it don't start right up and I can see a fluctuation in the volt meter I then go about doing a diagnostic check of the glow plugs. My diagnostics takes about 20 minutes. I simply remove all 8 glow plugs. I take them in my shop. Plug in a trickle battery charger. Dip the tip of the glow plug in a bit of grease or oil. Clamp the negative cable to the glow plug threads and touch the positive to the 3/16" spade. It will instantly spark and make a bit of smoke. The glow plug is good. If I see no spark and the glow plug does not smoke. I clamp the positive clamp on the spade and twist the ground a bit. Nothing happens the glow plug is bad. I break the tab off of it and scrap it in the steel scrap. I replace a set of 8 very seldom. I replace them as needed. And it seems to have worked for me for over 20 years. I have dozens of used glow plugs. I removed them from every CUCV engine I seen at the scrap yard and friends give me the used ones they change out. I buy new ones at the GM dealer 8 at a time for about $100. I only ever put a glow plug card in 1 truck. And that one started but would cycle the glow plugs for 10 minutes and make the belts scream. I read a book that was written by CUCV electric and bought 2 glow plug cards from him. I still have one new in the box. Never needed it. If the glow plugs work and it don't start it must be fuel related. So I keep after both systems. If any of my CUCV's start hard I get to diagnosing and fixing it. I will say slave cables are a great thing in extreme cold. I hook them up and start the first one and the second one is a breeze to start. I think that was the intent of the cables to assist in starting. I have 1 block heater I installed on my Mule M1009. But I have never used it. I use them on the plow trucks all the time during winter months. I am very tentative of every detail of my CUCV's. And I seldom have any issues with them. I always felt like if one thing don't work and I let it go . It is not long behind when 2 things don't work and from that point it is all down hill. I also do my best to just replace the defective parts. Not redesign the original design. I keep it stock and uncut. it has helped several times when I decided to sell one or two. Uncut and as designed holds true in many vehicles when it comes to resale. Take care and Good Luck with your starting issue. Happy New Year.

 

[2deuce]

Cucvrus, I have read your restoration posts and marvel at the lengths you go in your restorations. You are thee CUCV expert! I definitely respect what you have to say. If I was restoring this truck I would make it original, including the resistor too.
I bypassed the resistor, because I don't want to ever replace a glow plug again and since I bypassed it, I have not replaced any in 5 years. This truck has always started hard so the glow plugs are used about 3 or 4 times as much as a truck that starts as it should. Now that the glow plugs don't turn off after startup for about 2 minutes, I'm thinking they are receiving extra abuse and may lose some before this problem is fixed. I'm going to replace the temp sensor and get the fast idle/advance working. I know these are correctable faults that are putting a strain on the entire system. I still have questions how this system works, and feel I have a reasonable understanding of it. I would really like to know exactly what the card components are doing and not look at it as the brain of the system. Happy New Year to you well.

 

[Tinstar]

But it is the brains of the system.

The Glow Plug Controller Card determines everything.
It does rely on the temp sensor for GP activation, etc.
Determines afterglow. How many, etc.
Without the card......good luck.

I still recommend putting it back to stock.
Your not restoring, just getting it reliable again.
Install ACDELCO 60Gs
Quality GP solenoid
Replace both GP and Fast Advance sensors
Fast idle switch if needed. ACDelco still makes that also.

Buy the best parts you can afford. It does make a difference.
Especially in the long run.

Mine is bone stock.
Starts everytime in less than two seconds, if that.
Even when it's 3 degrees outside.
Still haven't used block heater.


Maintenance is extremely important on these.
Get behind with it and it will bite you in the behind

 

[cucvrus]

For the sake of argument/debate you are NOT bone stock in a CUCV with 60 G glow plugs. I have AC 13 G with 3/16" tabs. To set the record straight that is bone stock. I never have any issues with mine starting either. I just wanted to clear the air with the fact that 60G are NOT stock on a CUCV. He already mentioned that he had to grind down an incorrect set of glow plugs (1/4") to fit the correct (3/16") spades on the CUCV. I never done that. I followed the CUCV electric manual to the letter and have 0 issues. It is your truck do as you want. Happy New Year. For less then $100. you can buy 8 at a GM dealer.

 

[Tinstar]

System configuration
Not part numbers

Geese.......

 

[cucvrus]

No GEESE were harmed during my response. I am going out now to harm some hardwood. I also received a Milwaukee cordless grease gun as a Christmas gift. I am going out to put it to work. It may be more of an incentive to grease the CUCV's and all the other equipment.I was not trying to make and issue. just set the record straight. The man cut a new set of glow plugs tabs because he did not know the correct ones were still available. That is all I wanted to clarify. Have a great day.