Smoking GP module and resistors

i am not posting this in search of advice but more for informational purposes regarding the GP module... i was not sure where to post this as i did not want to jack another thread, but did notice my 86 model GP module is different that other pictures i have seen within SS.



Senario-
Went to start my 1028 this am....

wait light went through its cycle, and i tapped the starter for a split second.... did quite catch, so i hit it again and it fired right up.....

as i sat there warming it up, everything looked and sounded good, the relay chattered away and stopped like normal, but something just didnt quite smell right....

i hopped out and opened the hood to see a whisp of smoke rising off the resistor bank..... awe crap..... I had not yet put a fire extinguisher in this truck yet (6 weeks old)... turning it off i also noticed a whisp of smoke from under the dash....

gave everything a quick once over and found the GP module was the source of smoke under the dash....

best news NO FIRE!!!



the pain in my butt is the truck is half a block away from my tools and the TM.... lots of back and forth slowing progress....

I plan on retesting all circuits properly as the TM states (resistor included) then I plan on performing a temporary push button bypassing the GP module until i can repair or obtain an affordable replacement module.

the Diode that burned up is not on all the modules i have seen. Being that it needs to be replaced anyways, and i have seen others that do not have the same diode, i am tempted to remove it... but then there is the question of "Why?" it failed and not wanting to risk unnecessary damage.

Check the connections on the firewall. Id bet one of the nuts is loose.

By Pass that sucker, and install some AC60G glow plugs. You will be happier

Good thing it was not worse!

I would like to know if the difference in the cards components actually amount to a difference in the way they function. My original and back up are different.

allrevup said:

Good thing it was not worse!

I would like to know if the difference in the cards components actually amount to a difference in the way they function. My original and back up are different.

Click to expand...

Basically they should be the same, only the new one is missing one diode, the one that's burned out on the first picture, all other components(visible enough) are the same specification......

Confused again!

South dave, I though you didn't have to bypass anything if you use AC60G's, Just the blade width was differant? I thought I had this GP thing figured out?!

do not be comfused!

robesetz said:

South dave, I though you didn't have to bypass anything if you use AC60G's, Just the blade width was differant? I thought I had this GP thing figured out?!

Click to expand...

Well I am with you, this is what I have read in this and other forums.

The AC 60g have a 1/4" blade instead of the 3/16" of the AC 13g or Wellman's G070, this 2 GP's get hot quickly, maybe what is consider "Fast-Start" or "Fast Heating" in a properly working CUCV.

The AC 60s are "Self-Regulating" and the replacements for many Civilian 6.2/6.5 applications and requires a longer glow cycle to reach its absolute Hot temp, longer then the CUCV glow plug setup will allow it to stay ON.
That is why "you may need" a "manual ground switch" to keep then ON... say up to 10 seconds or in case the card fails altogether.

no connections were loose, gp relay tests good (recently replaced anyways) and the resistor bank looks and tests ok...

the glow plugs... 1 slight mushroom, 2 a small struggle to remove, and 5 were a total pain in the rear as they were swollen bad...

between the gp's and the resistor bank, it looks like my module stuck in the on position?....

ac 60g's in there now, cut the factory terminals off and replaced them with spades that fit the 60g's... (all 8 gp wires had corrosion within the insulation)

already have the push button physically wired in but not mounted yet.... would have fired it last nite but it was dark, my flashlight was dying and i want to easily be able so see if anything like the resistor bank starts smoking again....

i am also thinking about wiring the "wait" light so i can utilize the temp sensor to guesstimate engine temp in relation to how much if any the gp's get used before starting.....
the theory is "how cold is it".
from everything i have read the 60g's are self regulating, buy why work your batteries any more than you need to. after all the module does use the temp sensor as a critical part of its function.

I believe that if you leave the control card IN and cut the BLUE wire going to the card (since it is not working anyway) and ground and activate the GP relay with the manual switch your "wait lite" should work and if working it should also coincide with the seat belt buzzer

the purpose of the diode is explained in this thread
http://www.steelsoldiers.com/cucv/46669-glow-plug-control-card.html

the above link does not seem to work for me...


as i left the 1028 last nite, i double checked everything to make sure everything was on and tight.... leaving the hood open

key on, hit the push button for about 10 seconds (probably like 6 to 8 in reality) released the button, hit the key again and it fired right up....

as soon as it was running i jumped out to ho a physical heat test on the resistors.... slightly warm to the touch, slightly above the days ambient temp....

all looks good!!

try this
http://www.steelsoldiers.com/cucv/46669-glow-plug-control-card.html#post531365

that link works.... read that thread yesterday aswell.... thanks for reposting it...

so far all is well.... time will tell....