Hacked wiring M1008

[usmcgunner]

A fellow CUCV'er was over and noticed that the RED POS. cable from the right side of the resistor had been cut and terminated to the 12v block on the firewall (just right of the resistor). When the GP's are cycled (I put in a push button on the dash) I only get 10.5v at the GP's and at the lug on the relay. If I disconnect the output side of the relay, I get 13v +/-. Now I've replaced the GP Relay just for good measure since I was in there. So I know that's good. I checked the resistor and it's putting out 25v. Can anyone think of a reason why this was done? I've loked at the TM's, but they don't really address hacks. So my thuoght was to connect back up to the resistor so I can get full power to the glow pugs. As it stands right now, I don't get enough heat to start the engine. But if this was done because of some other issue, I don't want to fry anything. Side note: mine was retired into the Forestry Service before the PO bought it. I'll post up a picture in a bit.

 

[Warthog]

This is the Glowplug resistor Bypass that we talk about weekly. Many of the members have done this bypass. You can restore it to stock or leave it as is.

One of the drawbacks of restoring the system is that it can/will burnout your glowplugs.

Here is how the system works.

The glowplugs are 12v versions. They require about 10.5v to work.

24v is supplied to the resistor pack and the GP relay. When the relay is engaged the full 24v is supplied to the plugs.

Between resistance of the plugs and the resistor pack, the 24v drops to 12v and the plugs work.

Now if one of the plugs goes bad, then a little more voltage is supplied to the others.

Another plug fails, then more voltage to the others.

By the time seven of the plugs are bad, that last plug receives the full 24v and dies a painfull death.

 

[usmcgunner]

Here are the pics as promised.

 

[usmcgunner]

Oops, Sorry Warthog. I replied without refreshing. So what you're saying is I can do away with this all together. Ok. Then the 10.5v makes since. I thought this is why I'm not getting warm plugs. I'll replace the plugs and check back.

 

[goldneagle]

I would clean or replace the rusty terminals and nuts in the 3rd picture. Rust is not a good conductor of electricity.

 

[doghead]

What glow plugs do you have and what will you replace them with?

How long do you hold them on?

 

[usmcgunner]

I have new AC 60s to put in. The PO already replaced with 60s (7 out of and replaced 7 of the 8 connectors with female spades. I discovered one Wellman still in there. It doesn't want to come out though. As far as hold time, I'm up to aout 30 seconds and it still struggels to start.

 

[doghead]

10-12 seconds should be all you need.

Unless you have bad glowplugs(test them), you may have another issue like a air leak in the fuel system.

 

[usmcgunner]

Doghead, I'm leaning in your direction. I plan to do an electric pump swap in the near future. Maybe that will solve it. As for right now, I'm in serach of a way to get this plug out. So I'll be site: searching this evening. I replaced the controller card with antennaclimber's, it seemed to funcntion fine. The LED's really help. I noticed that the red LED indicator light he provided stayed on which he states shows a closed relay. I'm gonna have to start chasing wire now because I've replace just about everything in the GP system with new. I think I have a bad ground somewhere or the temp sensor is bad. I had ordered one from CUCV electric, but it never showed...along with the card I ordered from him.

 

[MarcusOReallyus]

So what you're saying is I can do away with this all together.

Yep. Resistor no longer needed. Judging by that nest, I'd say it's been non-functional for a while now.

No reason for it to be there any more unless you just like the looks of it.

I would clean or replace the rusty terminals and nuts in the 3rd picture. Rust is not a good conductor of electricity.

Yes!


I suggest you go THAT before anything else. Then test your voltages again.

 

[doghead]

One common air leak area is the sensor on the fuel filter base. Inspect that for any wetness.

 

[antennaclimber]

Doghead, I'm leaning in your direction. I plan to do an electric pump swap in the near future. Maybe that will solve it. As for right now, I'm in search of a way to get this plug out. So I'll be site: searching this evening. I replaced the controller card with antennaclimber's, it seemed to function fine. The LED's really help. I noticed that the red LED indicator light he provided stayed on which he states shows a closed relay. I'm gonna have to start chasing wire now because I've replace just about everything in the GP system with new. I think I have a bad ground somewhere or the temp sensor is bad. I had ordered one from CUCV electric, but it never showed...along with the card I ordered from him.

Just to clarify ;
The RED LED (on my GP card) indicates that the card is providing the ground output to close the relay. It does not indicate that the relay has actually closed.
It is there to indicate that the card is functioning.

And I agree with the others advice; clean all of the electrical connections.
Karl