glow plug relay
Cargo Master
Joined: May 2011
Posts: 2,623
Likes: 0
From: Rockford IL
I got him for ya! 
Id say add it anyway.. some of us do look through the entire thing just cuz u get that dang determined to figure somethin out.
Oh and tshrager... was at the OSU vs IL game the other day! lol I was on ESPN with my mom. Was an epic win. even though we only threw one good pass...
Id say add it anyway.. some of us do look through the entire thing just cuz u get that dang determined to figure somethin out.
Oh and tshrager... was at the OSU vs IL game the other day! lol I was on ESPN with my mom. Was an epic win. even though we only threw one good pass...
Lead Driver
Joined: Oct 2010
Posts: 5,127
Likes: 44
From: Columbus, Oh
I got him for ya!
Id say add it anyway.. some of us do look through the entire thing just cuz u get that dang determined to figure somethin out.
Oh and tshrager... was at the OSU vs IL game the other day! lol I was on ESPN with my mom. Was an epic win. even though we only threw one good pass...
Id say add it anyway.. some of us do look through the entire thing just cuz u get that dang determined to figure somethin out.
Oh and tshrager... was at the OSU vs IL game the other day! lol I was on ESPN with my mom. Was an epic win. even though we only threw one good pass...
More Turbo
Joined: Jan 2010
Posts: 569
Likes: 0
From: Missouri
Not to hijack to badly, If it is 20* or 110* I think my GPs activate and I say that because my volt gauge drops the same. Is this a correct assumption? I have always wondered by on a hot summer day the gauge drops if the GPs are not needed?
FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
Mine does the same if my switch is not activated. I was wondering the same thing. waiting for an answer
Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
It's all about EOT, not air temp. On my rig if EOT is 135 degrees or above then glow plugs do not activate. This was observed with Scan Gauge.
More Turbo
Joined: Jan 2010
Posts: 569
Likes: 0
From: Missouri
I still have the question. My oil temp could be 205* and still get voltage drop. Just wondering if this is normal or is there a problem?
Postmaster
Joined: Jun 2009
Posts: 2,566
Likes: 1
From: Monroe/Ellensburg, WA
GP's are not the only thing that draw power with the key in the ON Position... Hook up an LED to the GPR and you will see that once the engine is warm, your GPR will not activate...
More Turbo
Joined: Jan 2010
Posts: 569
Likes: 0
From: Missouri
I will have todo that and see happens. I did not realize that that big a draw with the key on would come from anything else.
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Postmaster
Joined: Sep 2007
Posts: 4,195
Likes: 6
From: Medford Oregon
With glow plugs ON voltage will drop below 12 volts and charging will not show much until they cycle OFF. If glow plugs OFF then as soon as the truck starts charging begins and voltage will jump up to 14.5 volts or so.
On Edit: I have my Scan Gauge set up for the warning lights to come on when the GPR is active. To do this program it to watch battery voltage and on mine if the battery voltage is below 12.3 Volts activate the warning lights. As soon as the GPR turns OFF the alternator kicks in and battery voltage goes above 12.3 volts so the warning lights go OFF .. instant GPR monitor.
More Turbo
Joined: Jan 2010
Posts: 569
Likes: 0
From: Missouri
Based on what you just wrote. My are always on at start up. My scan gage is set to show voltage and it takes something like a minute for the volts to come back up to 14.2 every start. This weekend i will set my gauge up like yours but I am 99% sure they are cycling every start.
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
It's not that the "alternator kicks in" after the GPs shut off. The alternator isn't controlled by the PCM. It's generating the whole time the engine is running. It's just that the GPs draw so much that it pulls down the voltage, even with the alternator. So when the GPs shut off, the voltage goes up, but the alternator is generating the whole time. Yes, there are other draws, most notably the PCM and IDM, but if the voltage starts out below 14-ish (usu 14.2), then goes up to 14-ish after a short time, that can only be the GPs (they're the only such load that's timed by the PCM).
PCM control of the GP relay is based on EOT, but IIRC, the time periods changed over the years. Later models, it would not activate it at all on a sufficiently hot startup, but earlier models always activated, even if for just a few seconds. But that's just based on my memory; there are charts of the time period vs. EOT, for various years, floating around on the forums somewhere.
PCM control of the GP relay is based on EOT, but IIRC, the time periods changed over the years. Later models, it would not activate it at all on a sufficiently hot startup, but earlier models always activated, even if for just a few seconds. But that's just based on my memory; there are charts of the time period vs. EOT, for various years, floating around on the forums somewhere.
