Glow Plug process overhaul

[epartsman]

I believe the intent of getting the piston to the top is so the broken tip is as close to the injector hole as possible to get it out. You do NOT crank the engine to get the piston to the top however. Use a breaker bar and socket on the pulley bolt on the front of the motor and turn the engine by hand. If you break off a tip you will remove the injector to hopefully fish it out. I have heard of some doing it with a shop vac.

If you take your time and don't try to force anything you will likely get them out without breaking one off. They make a tool to help if the tip is swollen. I have two different types, one by OTJ (I think) which you can find on ebay, and there is another company that makes an even nicer one, but the name escapes me. If no one else posts the name I'll look tonight and see what company it was.

jj&a racing makes the other tool which is far better and less money than the OTC tool. Also go to cucvelectric.com and get you a complete set up as I did. Legacy card, 60G's, Manual, Temp sender, Relay, connectors and all was about $200.00 including shipping but will give you everything necessary to overhaul your GP system with the latest and greatest all designed to work together.

 

[AmericanHaole]

Tonight, I measured the voltage to the glow plug relay and found it was getting a full 24+ volts. Decided that phase two was more important. I took apart the gp resistor and found it was burnt out. I cut the wire, added a new terminal and bolted it to the 12v diamond bus above.

Phase 2 is completed.

 

[mistaken1]

Just an FYI. In a fully functioning stock system you will measure a full 24V at that glow plug relay when it is not energized. The resistor will only drop the voltage when current is flowing through it to the glow plugs.

If the glow plug relay is energized and you are reading 24V at the glow plug relay then something is wrong. Either a shorted resistor or open glow plugs or a bad relay.

 

[AmericanHaole]

Is there a post that explains this? This is not the first time I am hearing about it, but I can't wrap my mind around a resistor that changes the resistance based on the amount of flow. Is there a post on this somewhere? In today's language, one might say it is a "smart resistor".

I am glad it motivated me to get it done. I actually removed the resistors and it turned into a two hour project. That car is hard on the knees! I did see something that looked like it was being shorted out, a charred gummy substance that crossed a resistor to the bolt.

Thanks for your guidance.

 

[doghead]

It's all listed in the -20 TM, in the troubleshooting section for the glow plugs.



As for the resistor, let me explain it like this.

Take a 12v battery, connect a resistor to a terminal. Use your volt meter and measure the battery voltage from the other terminal, to the resistor that is on the other terminal.

You'll get 12V. There is no load. With no load, you do not have a complete circuit. The resistor does nothing without a complete circuit(load).



Now, in the CUCV, the resistor is just sitting there in line with the battery, going to the glow plug relay. Until the relay closes(and has good glow plugs), there is NO LOAD. The circuit is OPEN. The resistor does NOTHING.

Where it gets confusing is, the voltage will drop when the GP relay closes, and the amount the voltage drops is proportional to the combined resistance of the resistor bank and all 8 glow plugs being good, or it will not drop enough(if one is bad). If that happens, the voltage is too high for the rest of the glow plugs and causes them to burn out.

That is why we suggest you resupply the GP relay with 12v. Then, when one does burn out, it has no effect on the others.

The military designed the system with 24V, NATO slave jumping optimized. We do not need that.

 

[1stSarge]

Try this on...

Resistance is Futile - CUCV Electric

---Note the correct spelling dh---

 

[AmericanHaole]

No resistance to the lightbulb over my head

I see what you mean now. A resistor is not constant. I always thought a resistor was a limiter, or a reducer, like connecting a straw to a hose.

Thank you doghead for explaining it.

CUCV Electric's website was great. Thanks for sharing.

(For what it's worth, I did do well on my Ham Radio License.)