Earlier this winter when the temps got down into the 20's and i forgot to plug in i had no problems getting the truck to start right up after a couple times cycling the heater grid. As the truck sat idling and warming up i would notice drops on my volt meter and dimming of the headlights/dash lights until she got warmed up good, which i know is normal.

The other day temps got back down into the 20's (not plugged in) and i didn't think i was going to get her started at all before the battery pooped out on me..... but it did finally start after cycling through the heater grid 4 times and a little bit of cranking. It ran rougher at first than it ever has. I also noted that i wasn't seeing a drop in the volt meter while warming up. Throughout the rest of the day i didn't have any problems starting the truck. I wrote all this off to it being cold outside in the morning and the fact that i hadn't plugged in.

But..... yesterday morning the temps were up to 40 or so and i experienced the same problems as the morning it was down into the 20's. Not that cold outside this morning, i was thinking. Something just doesn't seem right and i want to get a handle on it before i'm stranded and looking for a ride to work.

A couple things to note- when i turn the key on and the WTS light is on, there is a definite pull on the battery and the "click" as the heater cycles off and the light goes out... so i'm guessing the heater grid is working okay....... but why did it not cycle on and off while sitting and idling after finally starting the other day? Also, the PO installed a battery that is undersized for the truck (i think its only like 850 CCA).

Sorry for the novel but i'm just a newbie looking for some advice and i wanted to be as specific as i could. I'd appreciate any advice from ya'll.

 

The 4 grid cycles at 40 degrees is the key to this puzzle. Things were warm enough in there after the last time you cycled the grids that the PCM thought the grids were unnecessary. The PCM has no way of knowing how many times you tried to start the truck, so as far as it was concerned on that final attempt it might have been 60 degrees outside.

My truck had no grids last winter due to melted relays and it started just fine down to 17 degrees unplugged. If the truck is cranking slow after you run the grids due to a weak battery, start it like a gasser - just hop in and hit the key. It'll crank faster and start better without the grids dragging the battery down for 20 seconds. The grids are more of an emission control device than a starting aid, they really don't help with starting until you get in the single digits.

 

Okay that makes sense and explains the no cycling after i finally got the truck started. But what i don't understand is that i've never had a problem getting her to start right up the first try... like within about a second of turning the key after letting the grid heater cycle once. Lately i've been cranking for several seconds before i go through the whole routine again.... thus draining the battery. Or maybe i got hold of some bad fuel this time around? Should i try some fuel conditioner and if so what is the recommended brand/type? Should i go ahead and replace the battery with the correct one rated at higher CCA... like 1250 or so isn't it? Or should i just jump in her and crank her right up like a gasser like you said above? Thanks again.

 

You could try some additive, I doubt you guys get winter blend fuel down there. Power Service is very popular, get the stuff that says cetane boost on the bottle. It's sold just about everywhere, even Wal Mart. A bigger battery wouldn't hurt any. Don't be afraid to crank for 15-20 seconds at a stretch, that will help more than cycling the grids again. Cranking builds more heat in the cylinders.