I should already know the answer to this... but I don't

How long does the PCM keep the GP's on for the first cold start of the day?

Reason I ask is that I can't plug my truck in at work and it's darn could out today. I'd like to cycle the GP's 2 full times before I start it up. Figure I'd turn the key to on, and come back to cycle them over again (luckily I'm the first one in so I park close to the door at work)

Think I'm going to need to wire up the GP's on a switch so I can leave them on for about 4 min before I try and start is on cold days w/o being plugged in

Thanks

Robb

 

2 minutes...

 

Cant answer how long exactly, I am going to guess a minute or more. Did you know they are actualy still on after the wait to start light goes out? My truck starts easier and runs smoother if I wait for 10- 15 seconds after the WTS goes off to kick it over. You can time how long they are on after you start the truck by watching the volt gauge, a minute (maybe I have never timed it) after it is running the voltage will suddenly jump up a 1-2 volts, that's when they shut off.

 

Thanks for the diagram, I didn't have that. Always good to keep those around

Butch, Yes, I am aware that they stay on long after the WTS (aka idiot) light goes out and the truck starts. I just want to give my truck the best chance to start with it in the single digits temp wise today with no place to plug in. Figured a 4 min cycle, 10 second break then kick the starter and see if that works.. will need to find a winning combo because it's only getting colder here...

Thanks

Robb

 

Do you think all the GP's are good?...I am going to Ohm them out this weekend to see if any are weak or inoperative...

 

Yes, replaced them 2 years ago (I think? maybe 3...). I also have new batteries, battery cables, a Stancor 586-902 GPR, new starter relay and new starter. Basically everything related to cold weather starting has been replaced. I am still running 15W-40 and will continue to because I think it's better protection for the engine, even though it's a little thicker in the HPOP in the winter months

I'm just trying to find the best combo for timing the GP's and the starter, because as we all know the WTS light might as well just say "good morning, how are you today?" because it does no good telling you when to start your truck

 

Do you have a block heater?

...Sorry I missed that...need more coffee, I am not awake yet! ...

 

Haha I hear ya. Been up since 4:30. already on coffee #3.

Yes, I do have a block heater, which I have on a 3hr timer that I use in the morning. The problem is at night, I work from 6am-7 or 8pm and the truck sits all day and I have no where I can plug it in...

Robb

 

OBS trucks = 90 seconds

SD trucks = 120 seconds

 

You can also insert a (SPDT) switch in the GPR control lead from the PCM. It can give you the option of letting the PCM control the relay or you. If you try it, I'd suggest adding a LED or other indicator to show you are in 'manual GPR mode'.

Only drawback I can see is setting a code if the PCM monitors the GPR control lead for continuity.

 

I think if you leave your GP's on for 4mins. you will burn them out very fast

 

Mine lasts for 120 seconds... I will get a video of it next time that I start the truck up with it below 23 degrees.

 

Install an LED on the switched side of the GPR so you know exactly when and how long it stays on for.

 

Exactly what i have.... just hasnt been cold enough yet.... still hasent even snowed yet here in denver.

 

Good idea on the LED. I'll have to throw on on there

Robb