what is the draw on a solid state GPC?

IDIoit

MachinistFabricator
Joined
Aug 26, 2014
Posts
13,438
Reaction score
4,186
Location
commiefornia
my truck needs a bit of work.
nothing too crazy just some things ive been putting off.
one of the things im worried about is the wiring of my glow plug controller.
I have a 8ga wire from the heavy side of the controller to the battery.
incase of a total melt down of the solenoid, I want some protection.

what is the average draw of a properly working glow plug system?

I will be installing a circuit breaker type cut off.

thanks folks!
 

chillman88

Full Access Member
Joined
Feb 22, 2017
Posts
6,111
Reaction score
6,319
Location
Central NY
I blew a 175 amp fuse at 60 degrees outside. I haven't blown the 200amp even in 20 degree weather. I have 4ga wire going to mine.

Edit: this is with new plugs and a new harness too.
 

IDIoit

MachinistFabricator
Joined
Aug 26, 2014
Posts
13,438
Reaction score
4,186
Location
commiefornia
my entire system is new.
down to every last piece of shrink wrap,
it works great, I just want some redundancy.
I have a 200A breaker for it I plan to install.
appreciate the input
 

laserjock

Almost there...
Joined
Nov 20, 2012
Posts
8,851
Reaction score
3,142
Location
Maryland
I need to look but I think I put mine on either a 150 or 175 amp fuse. The inrush is up over 200 from what I remember from Bill's test rig but it drops quickly down to something smaller. I want to say a bit over 100. The big inrush is why I went with a slow blow fuse rather than a circuit breaker.

Edit: Bill's test showed the inrush to be closer to 185.
 
Last edited:

icanfixall

Official GMM hand model
Joined
Apr 10, 2005
Posts
25,858
Reaction score
681
Location
West coast
Look at what the factory engineers did for the solid state controllers. They ran 2 small wires parallel in the same lugs but. Look at the main engine harness plug connections. They are VERY small for the load draw.Any dirt or corrosion in this plug and you get plenty of heat. Many truck electrical fires start at this plug. One morning start I saw smoke escaping from the hood to fender joint. Thought my starter failed but nope. While moving wires around I felt lots of heat in the plug. Found it melted where the 2 yellow wires in tandem feed power to the controller. Fixed it with multi strand speaker power cable purchased from stereo shop.4 gauge wire too run directly to controller now. Please remember this feed wire is ALWAYS hot. Like the alternator they are always having battery power to them so accidentally grounding this wires will cause the magic smoke to leak out of the wires very quickly.
 

OLDBULL8

Good Morning Ya'll.
Joined
Feb 12, 2009
Posts
9,923
Reaction score
342
Location
Delphos , Ohio
As laserjock noted above for amperage.

If your going to fuse the GPC relay, use a slow blow fuse, a 175 amp will do. Using a circuit breaker, a 150 amp will do.

Circuit breakers are slow to trip unless you have a dead short. You have to be careful of what breaker you use. A household breaker is rated at 600 VAC and 250 VDC , Marine breakers are rated for DC volts. Some breakers can be adjustable, Instant trip or delay trip.

Those guys using a Circuit Breaker on there Glow plug relay power better be careful on what kind there using.

http://www.abt.com/product/60825/St...d^1100404199103-sku^60825@ADL10BMC-adType^PLA
 

shawn deere

So many wrenches, so little time...
Joined
Dec 29, 2016
Posts
445
Reaction score
82
Location
nebraska
Holy smokes, i have a new respect for the glow plugs now, didnt know they pulled near that much
 

icanfixall

Official GMM hand model
Joined
Apr 10, 2005
Posts
25,858
Reaction score
681
Location
West coast
Actually, those are most likely two fusible links running in parallel. That's how a PSD is wired.
No fuseable link in this line. I removed mine completely and no fuse was found. Its common knowledge in the electrical industry its cheaper to run 2 or three small wires than it is to run one large wire. Just look at any high voltage cable on this 200 to 300 ft tall metal power towers. 500,000 volts you will see 3 lines in a triangle run per bundle on these towers.
 

Hydro-idi

Full Access Member
Joined
Nov 8, 2011
Posts
2,273
Reaction score
361
Location
Lodi, California
Good idea to integrate a fuse for these gp systems. Something I never really thought of to be honest.
I did fry a GPC after installing my rebuilt engine in. Not a good feeling when you see smoke bellowing from hood of a 30 year old truck lol.
 

snicklas

6.0 and Loving It!!
Staff member
Administrator Moderator
Joined
Aug 7, 2006
Posts
6,215
Reaction score
2,455
Location
Greenfield, Indiana
One other thing I discovered with the solid state controller. Specifically the Z Shaped resistor on the controller, this Z-Shaped resistor gets VERY HOT when all 8 glow plugs are working correctly. If you have not had a correctly working system for a while, either a bad plug(s) or "incorrect" plugs, you may find yourself with a little surprise.

When we replaced the Delphi plugs with Motorcraft plugs and replaced the Glow Plug Relay the bakelite case crumbled on, I had everything apart. I even removed the entire controller to clean everything up, and replace the relay. When everything was put back together, I left the black plastic cover off so I could watch the controller and wiring. Had my son turn on the key and I stayed up top to watch everything, Once the relay kicked on, I counted to make sure the controller turned off in a proper amount of time. At about the 9-10 second mark, the Z-Resistor started SMOKING. I had him shut the key off, triple checked the wiring, even looked at pics on here. Got out the meter, hooked across the resistor and saw there was a voltage drop... so it should be working. To make sure I hooked everything up right, I pulled 3 glow plug connectors, to force the controller to short cycle, because I was beginning to wonder if the controller had failed..... With 3 plugs out of the circuit, at about 4-5 seconds, click...click....click..... So the controller was working. Hooked each one up, one by one, and each time the delay got longer. So had them all hooked up, and just "let it go"..... It smoked again, and at about 12ish seconds, the WTS light went out and the relay opened like it should. Over the time the plugs weren't working correctly, crap collected on the resistor, and the first time there were 8 Brand New ZD-9 plugs all lit at the same time, it heated the resistor enough to burn the s**t off of it. It was working as it should.... it is just a surprise at first just how hot the resistor gets......
 

IDIoit

MachinistFabricator
Joined
Aug 26, 2014
Posts
13,438
Reaction score
4,186
Location
commiefornia
like Scott said, they do get hot, so don't go touching the bar after you cycle your plugs!
this was one of the very first things I learned about these trucks, before my oil burners days.
but in hindsight, that finger will likely never produce the same print again! lol
 
Top