Had an unusual issue this am.

Since it was crazy cold here, I plugged the block heater in overnight. (I usually only plug it in 2 hours before I start the truck in the am). Truck sits outside all the time. It was -8F overnight low, maybe 0F when I went to drive this am.

I did the "double warmup" thing; turned the key to on, waited for the "wait to start" light to go out, immediately turned the key off, and then back to on again, to cycle the grid warmers 2x before starting. The truck started like it was a summer day.

Drove 3 miles, pulled into a local shop, left idling for 5 mins. Running fine. When I went to pull away, the truck was stuttering and stumbling badly. No noticeable smoke. Downshifting didn't help, might have been slightly worse. Couldn't get above 30mph; was getting concerned I was going to have to walk!

I made it home, put it in the garage where it was slightly warmer than outside temps, and plugged it back in for a few more hours. Started fine, ran fine the whole rest of the day.

Guessed it was a fuel gelling issue. Bought the last bottle of Power Service Diesel 911 from WallyWorld. Topped up the diesel from a different station than I usually use (In case my normal station's diesel wasn't treated properly for winter).

What did I experience? Gelling fuel? Weak batteries with heavy electrical demand? Something else?

 

I was thinking gelling fuel myself.
Any white smoke along with the stuttering?

I was -25F this morning when I fired off the '95 12V to bring my daughter to school and I only gave it a little over an hour with the block heater plugged in.
It acted like the fuel was a constricted and it would lightly stumble and white smoke the first mile or two.
Gave it a shot of the white diesel power service bottle myself.

 

No white smoke that I noticed; I did look to see if it was smoking during the limp home.

I'm guessing that due to the block heater, the fuel filter housing and associated lines were warm enough for the first 3 miles. Then maybe during the drive, the airflow thru the engine compartment allowed everything to cool down. This, plus maybe some not-quite-winter-spec fuel could have caused the issue?

I sure don't care to repeat this! Guess I should plan on tossing in a bottle of 911 or PS whenever we're looking at temps this low? I used to do it regularly 10 years ago, but stopped doing it. Never had a problem until this winter...

Also, how do you guys avoid driving off with the block heater plugged in? My memory must be fading, I haven't done it EVER in the first 13 years of owning the truck; but I've done it 3x already this winter!

 

Diesel 911 is for emergencies only, white bottle of power service or howe's to prevent it. The 911 stuff isn't good for injectors or pumps, but will thin out jelled fuel enough to get it running once it has jelled.

I usually drape the cord over my rear view mirror so I see it first thing.

I still find it amazing how good sub zero temps are at finding weak links... could be several things, usually jelling causes some visible smoke. Something in the VP cooling down and throwing it out of whack once enough cold fuel went through it....any codes?

 

Yeah just give it a good shot of PS white bottle if it is calling for a really good cold snap.
Fuel is treated in any given area for what they predict will be a rough low temp.
At the 18 wheeler truck stops around here it will post what the temp is the fuel will gel at.
If it is calling for an unseasonable cold snap I grab the PS and give it a shot.

As far as the block heater, I only plug it in if I feel it is cold enough and hour or so before I need the truck. That and the fact that I have to walk right by the orange cord in the snow to get to my truck, makes it hard to forget.
If it is not about -10F or below I don't even use it.
I also use synthetic oil for the winter months.

 

2 hours on the block heater may not have been enough at those temps, I set mine for 4 out here on the coast....

I'm thinking gelled fuel also. Not sure if the block heater would emit much heat over to the fuel filter housing, but it might. I'm gonna feel it next time I plug in if I remember.....

 

three cyl idle comes to mind ,mine will do it after warm up if left idling at below zero temps.........it cools off real fast at a idle

 

I considered high cold weather idle, but thought it disengaged once you started moving.

Something to look at....