Intake heater grid circuit

[driverswanted]

Does anyone have the text that explains the glow heater grid time vs. temperature? I am having one of these circuits made for my 4BT that now has a 6BT grid and shortened 6BT intake plate. I need to know the grid sequence for the "pre-heat" phase. I don't know if the circuit turns both heaters on for all temperatures below 59F or does it use one or two grids based on the ambient temperature.

 

[MAX A/C]

Looked in my Haynes manual for 1994-1998 models...

Above 59*, no heat.

15* to 59*, 10 seconds pre-heat.

0* to 15*, 15 seconds pre-heat.

below 0*, 30 seconds pre-heat.



Post heat with the above three pre-heat cycles but no times indicated. Also, the book makes no reference to only one working at times--refers to both working each time. Hope this helps.

Scott

 

[driverswanted]

I do have the after pre-heat cycle information. It does, by the way, alternate between the two grids when in engine running mode. At least that's what my single page from the facory manual has on it. It may use both grids at the coldest temperatures. Not sure though.

so it sounds like both grids are on in the pre-heat mode.

 

[JLEONARD]

I know the marine grids alternate.

 

[BushWakr - RIP]

Here it is right out of our manual.....



https://www.turbodieselregister.com/forums/showthread.php?t=31560



pb

 

[driverswanted]

Does it use both grids in pre-heat when at all grid active temperatures?

In engine running mode do the grids alternate for the listed seconds until above 59F or is there any "no grids on" time during the cycling? That is, is there any off state in the duty cycle.

 

[Paychk]

Yes both are used in pre-heat mode. Post heat mode can use both or alternate one then the other, depending on the temp. The FSM doesn't state at what temperature set point it will go to alternating. In the post heat cycle there are periods when both heaters are off. That is why your head lights & alternator gauge show normal voltage levels.

 

[driverswanted]

Post heat off

Could you probably have the thermistor temprarily above 59F when both are off in post heat and have them come back on when colder intake air chills the thermistor back down below 59F? I don't see anything in the chart to otherwise explain this.

 

[driverswanted]

Ah, I see a Bossier City as an address. I worked for Schlumberger in Shreveport for some years.

 

[Paychk]

The manual dosen't specify what happens if the thermistor goes cold again, quickest way to find out would be pull it from the intake, plug the hole and put it in water. Or if you have a spare sensor, once the engine is warm, move the wire from the engine to the spare in some cold water.



I see the blue & white convoys all the time, coming & going across the Jimmy Davis. I bet you miss the winters down this way, I'm looking to move home to Oregon this next summer.

 

[driverswanted]

Good idea on teh extra thermister. I do have a spare I can test with.

Used to live on Preston avenue in Shreveport. Miss the fine food down there. Had many Dades while I was there.

 

[PeteFleming]

Does anyone have the text that explains the glow heater grid time vs. temperature? I am having one of these circuits made for my 4BT that now has a 6BT grid and shortened 6BT intake plate. I need to know the grid sequence for the "pre-heat" phase. I don't know if the circuit turns both heaters on for all temperatures below 59F or does it use one or two grids based on the ambient temperature.

I was reading about the wait to start light and water in fuel lights flickering during grid heating being described as normal for gen 1. I just started having the flickering on and off. Found that when lights flicker, grid heater solenoid(forward one) vibrates because of worn. dirty contacts(shot). When it makes good contct, then lights do not flicker. Solenoids for grid htr are not available . . found them as western snow plow parts on the web (Mill Online Store) part # 256-0515 (need 2) at $10 ea. plus shipping. These appear to be the ones. . will let you know if they turn out not to be.