Glow plug issue

[cobia2017]

Hey guys, appreciate any help you guys can offer....issue: wait light on for a much longer time than usual occurred gradually but i can still hear the relay click but it takes like 30 seconds at least and motor will not start cold. (without starter fluid) I checked all glow plugs and about half were not working, so i replace them all so that now all glow plugs are working but still same exact problem, so I started testing the harness - test light at the green wire feeding the individual plugs gets no light, test light at the the glow plug relay where the input wire from the ignition switch attaches does light up, next I was testing the bigger two orange wires from the copper studs exiting from the relay when I noticed some smoking from the resistors and of course turned off ignition. and stopped the process it was getting dark anyway....Thoughts? resistors bad all of a sudden now that the plugs are all new and making the circuit complete? plugs are 60G ac delco. I wouldn't think its the fuseable link prior to the resistor from the buss bar?...I have reviewed threads on here and the wiring diagram but am stuck, any help really appreciated, Thanks Robbie

 

[antennaclimber]

Check the voltage on the orange wires at the GP relay with it closed. It should be around 12 volts. Open should be 0.
The wire from the resistors should be around 24 volts open relay, and 12 volts closed relay.
The green wires will not have any voltage on them when the GP relay is open. When its closed, around 12 volts would be normal.

The resistors may emit some smoke if they have dirt and other crud on them, this means that they are doing their job.

In cold weather, the Wait light can stay on as long as 30-45 seconds.

Read the GP Theory of Operation to help you understand how the system works.
GP Module Theory of Operation

 

[cobia2017]

Check the voltage on the orange wires at the GP relay with it closed. It should be around 12 volts. Open should be 0.
The wire from the resistors should be around 24 volts open relay, and 12 volts closed relay.
The green wires will not have any voltage on them when the GP relay is open. When its closed, around 12 volts would be normal.

The resistors may emit some smoke if they have dirt and other crud on them, this means that they are doing their job.

In cold weather, the Wait light can stay on as long as 30-45 seconds.

Read the GP Theory of Operation to help you understand how the system works.
GP Module Theory of Operation

when you say "open" do you mean the relay has not magnetized the core to touch the copper studs yet?f and closed is when it has and you hear the click?

 

[antennaclimber]

when you say "open" do you mean the relay has not magnetized the core to touch the copper studs yet?f and closed is when it has and you hear the click?

Yes that is correct.
The relay is merely a remote controlled switch.
Open means the GP's are not getting power applied to them, Closed means the GP's should be getting voltage from the vehicle power system.
In your case, that is from the resistor.

 

[cobia2017]

Yes that is correct.
The relay is merely a remote controlled switch.
Open means the GP's are not getting power applied to them, Closed means the GP's should be getting voltage from the vehicle power system.
In your case, that is from the resistor.

Ok narrowed it down to the glow plug relay and got part number AR 145 at Napa, which I failed to get to work…however Napa relay part number ST81SB did work (it looked much more like my old existing relay)….I never could get the smoking resistor to stop smoking in my comfort timeframe despite cleaning it with wire brush and compressed air (perhaps more time of allowing dust to burn off would have worked) so I removed the resistor and circumvented it via the 12V re-route as per others have described on here…truck starts up quickly on cold start now! Thanks for your help today really appreciate your time

 

[MarcusOReallyus]

(without starter fluid)

Starter fluid in the engines is playing Russian Roulette. Don't do it.