Is my grid heater confused?

[Mel Fuelling]

Twice this past week here in SW Iowa the temperatures in the morning have

been -21F. My 93 CTD work truck block heater was plugged in and started

promptly. The drop in the voltmeter reading indicated that the grid heaters

actuated but stayed on for about 5 minutes on the road without cycling off.

I was watching anxiously, hoping it wouldn't catch on fire. It didn't. At -11F

2 following mornings, when I turned the key on, the grid heaters didn't come on, I started it and the grid heater came on, but the wait to start and water in fuel lights flickered like a slow starting flourescent until the grid heater cycled off in about 2 or 3 minutes (I left the block heater plugged in until the grid heaters turned off) , then the indicators quit flickering.



Are these symptoms of grid heater temperature sensor and/or computer problems?

Has anyone else had a similar experience?

 

[WyattEarp]

i tell u what its truly amazing what such cold air will do to our truck, i haven't had the issues you speak of but i have had the wait to start etc. . lights act very odd when it gets to a certain point of cold out. . I call it the winter Gremlins, but with my truck plugged in i have not had those issue only when not plugged up.

 

[PToombs]

It's so cold out that when the turbo pushes that cold air in the sensor tells the computer and it causes the grids to cycle.

If the other lights are flickering you need to check and clean the grounds. Sounds like the grids are drawing a lot and it's grounding thru anyplace it can.

As for leaving it plugged in while it's running, that's a no-no. If you get cavitation near the heater it can burn it up. It should stay warm for an hour or so after you unplug it, even in those temps.

 

[Mel Fuelling]

Pete,

I hadn't thought about the possibility of cavitation that you mention. Will

cavitation occur before the thermostat opens?



Wyatt Earp,

I am relieved to hear that my truck isn't the only one with wait to start and water in fuel fluttering at low temps. I will check grid heater connections for corrosion and contact. I would like to avoid the grid heaters being "stuck on" for five minutes in the

future if I can.

 

[Midnite]

I wonder if your grid heater relay is going goofy. It's an easy thing to check--just swap it with one of the others of the same size.

Mike

 

[JLEONARD]

Mel I think YOU are confusing your grid heater. . plugged in, not plugged in, telling your truck you love her yet making her run at -21. :-laf



I also had goofy things happen when the temps got really low and I wasn't plugged in. I've had the grids stay on for what seemed like an eternity.

I attributed it to living in the rust belt and having ground issues when metal things got cold and contracted... . shrinkage strikes again.