7 degree YEAH, 0 NO :(

[robbertwilliams]

Yesterday, I started the car at 7 degrees, without even being plugged in, it did take a couple minutes of cycling the plugs, but it did start.
Today, 0 degrees, car plugged in and heater working fine, NO START. It doesn't even catch once, just turns and turns. What could be the culprit?

[82vdub]

Glow plugs burned out since yesterday, glow plug fuse is blown, fuel solenoid isn't working, fuel gelled in IP, fuel siphoned out of IP, block heater not working, and old battery (slow cranking speed) are things that come to mind. Hard to say without other data.

Also, how long was it plugged in before you tried to start it, and are you sure that the block heater actually warmed the block? Even though it's a 7 degree difference, it could make a world of difference.

[robbertwilliams]

Diesel, once gelled, what do you do? Just wait for warm weather? Also, glow plugs were definitely drawing this morning based on the volt gauge. But now, this afternoon, when I turn the key I can still hear the relay click but it doesn't appear to be going from the normal 11v (when plugs are on) to the 12v (when they turn off). But maybe the plugs aren't staying on as long since the block heater has been on since this morning, so maybe the temp sensor is telling them to shut off earlier.

[Quantum TD]

Spray some WD-40 into the intake. Less-potent than starting fluid, the car will fire and spin easily. Starting fluid is jarring on these 4-cyl diesels. WD-40 has enough aerated oil to make it less-horrifying.

[robbertwilliams]

Fuel Gelled...first time that has happened to me. Left the car plugged in for a couple days, started right up just as if I were leaving the beach on a hot summer day. Thanks for help on speculating the culp.

[82vdub]

Glad you sorted it out. How did you find that the fuel gelled?

[robbertwilliams]

I tried draining the fuel filter...nothing came out but a few drips but there was fuel in the line

[82vdub]

There's also a water separator in the fuel filter. If you have not changed it lately, I'd change it. Even if you did, I'd still change it to be safe.

[Fatmobile]

Diesel 911 is the only stuff I have heard of that will melt gelled fuel after it has gelled.
Many others that can be used to prevent gelling.

There is a vent hole on top of the fuel filter that sometimes needs to be opened to let air in, if you expect anything to come out the drain.