Glow plug resistor

[86k10]

I have a question about that big resistor on the firewall, I was trying to get the last one of my fleet running and checked the glow plug relay and there is 24 volts there. And yes it doesn't work, am I to assume that the resistor is bad and therefore took out the relay. My 1028 has the glow plug relay hooked to the power block just above it and seems to work fine, is that an acceptable way of doing it or do I need to get a different resistor.

 

[acetomatoco]

With no load you will get 24 volts at the output of the resistor.. when you put the glow plug load on the voltage drops to the required amount and the rest is dissipated in heat thru the resistor. The relay operation has no connection to the high voltage.. there is a straight thru path for the amperage when the relay is actuated... The purpose of the resistor pack was just to allow 12V to the glow plugs when jumping with the NATO plug when the batteries were frozen...in that state, there is no 12 V available from the jumper between batteries and the 24 V is all that is available.. ACE.

 

[86k10]

Well it seems that is not the problem, I traded relays and still nothing. There is power only on the top input terminal even with the key on. What do I need to look at next.

 

[acetomatoco]

Probably the glow plug card... see Jeff at Frontline for one... ACE

 

[86k10]

This truck is one I'm parting out and when I got it the IP was off and laying in the cab. I just put it all back together to see if it would run or not. There was a service record in it talking of an engine knock, so I just figured let's see if it's true or not. Believe it or not I did manage to et it started and I can hear what they were hearing but it doesn't sound like a bearing knock or something of that nature. It sounds to me like a diesel ping, or perhaps a carbon knock since it sounds to me like it is up high, I never did get the glow plug light to go on but it flickered while cranking, is that normal? I figured I'd ask here and if anyone reads this that has maybe experienced the same symptom.

 

[CCATLETT1984]

just go with a manual switch for the GP's, see the sticky post regarding how to do it.

 

[86k10]

I may have found the knock today, I was loosening injector lines to see which hole was missing and it seems number 3 loosened up makes the noise go away even when reved up. I guess we'll try some new injectors.

 

[jfmrj]

I've heard about bypassing the resistor. Where do you put the wire that runs out of the resistor if you replace it with one off the block on the firewall or just run a fusible link from the positive terminal on the front battery?

 

[Michael]

I hooked mine up to the 12volt buss just above the relay.

 

[jfmrj]

I got rid of the resistor and ran a wire from one of the batteries and the blazer still isn't starting. I'm still only getting 4 volts to the glow plugs. I was wondering if a bad ground could cause this and if so how do you check that. Are the military glow plugs the same as the civilian ones?