Pre-Heater Cycle (Cold Weather)

[rjohnson916]

Started my truck this morning, as you may or may not know California has had some really unusual weather patterns in years. It's been 34-24 degrees for the past week. Anyway today when I went to move my truck out of the drive it said it was 45 degrees on the overhead readout. Anyway, the wait to start coil came an as it normally does, but the tick, tick, tick, tick..... I also usually hear wasn't present. My truck has intermittently done this since new, also I've had the tick, tick, tick, tick ..... come on in the Summer months too, sometimes when 80+ degrees out side. At what temp is the grid heater actually programmed to cycle?



-Ryan

 

[rbattelle]

The pre-heat cycle will occur if the inlet air temperature sensor indicates <66°F. For 15-66°F, both heaters come on for 10 seconds. For 0-15°F, both heaters will preheat for 15 seconds. Below 0°F both heaters preheat for 30 seconds.



After startup, for 30-60°F and RPM>1000 the following post heat cycle will run:



1. Both heaters on for 10 seconds

2. One heater on continuously for 90 seconds. That means one grid will be on at all times, but the two grids will alternate every 5 seconds or so.

3. One grid on at a 50% duty cycle for 40 seconds.



For post heat at RPM<1000:



1. Both heaters on for 10 seconds.

2. One grid on at a time running at 25/75 duty cycle.



For those who don't have LED's connected to their grid heaters, I highly recommend that mod! It's fascinating to watch them do their thing and how they adjust depending on engine RPM. It's kind of clever.



Ryan

 

[sfr1047]

rbattelle,

Now explain the procedure for the led mod and what voltage led.

 

[Pawpaw]

For those who don't have LED's connected to their grid heaters, I highly recommend that mod! It's fascinating to watch them do their thing and how they adjust depending on engine RPM. It's kind of clever

I hadn't heard about that mod. Is there a thread about it?



It does sound interesting.



Bob

 

[rbattelle]

It's not difficult, you just need a couple LED's and a couple resistors. This site explains very nicely how to calculate the correct resistor for any LED you want to use. And here's my thread on the subject.



Enjoy!



Ryan

 

[Prairie Dog]

FWIW, You can get LED's at rat shack that run on 12V w/o an extra resistor (the res is built in). I use an amber one to indicate low F. P.



Scotty

 

[rbattelle]

FWIW, You can get LED's at rat shack that run on 12V w/o an extra resistor (the res is built in). I use an amber one to indicate low F. P.

There you go, even easier! It's almost criminal not to do it!



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Ryan