How does the "preheater" work?

[simoncrk]

Is the preheater on the dash of my deuce kinda like a glow plug? Where are they located on the engine?

 

[WillWagner]

It is in the intake. There is a fuel line from the low pressure side of the IP across the engine to a small injector and a glow plug right next to it. At the top of the pages here is a tab labeled "resources". Click it and go to the TM section. Download TM9-2320-361-10. That manual will give the basic operation and location of controls on your truck. I keep a hard copy in the truck so if I forget, which is highly likely, I can find things!
HTH, Will

 

[simoncrk]

Thanks!!!!
Many Thanks.

 

[RANDYDIRT]

How do you know if the preheater even works? I can't tell the difference one way or the other, it seems to start the same if I use it or not. Is there an easy way to tell if it works?

 

[WillWagner]

I know when it is cold here...35 or so...I know, I know, you east coasties don't think that is cold, but it is for here Mine is kinda slow to start. If I use the flame heater, it starts and idles fine when the switch is thrown and if I let off it idles funky 'till I throw the switch again. Guess it works, that is how the manual says that's how to use it.

 

[Capt.Marion]

What it consists of: a sparkplug in the intake manifold, an ignition coil, and a fuel injector next to the sparkplug in the intake.

How it works: when you flip the switch on the dash and hold it, the injector sprays diesel into the intake manifold and the sparkplug ignites it, so there is literally fire going into the cylinders.

How to use it: ONLY ONLY ONLY flip the switch when the engine is being cranked or is idling. Bad things will happen when there is rapidly expanding hot gas and fire in the intake manifold with nowhere to go but backwards.

When you are starting the truck, hold the switch over while cranking the engine. As soon as the engine catches, give it some throttle (NOT ABOVE 1000 RPMs), and flick the switch and hold it as needed to keep the truck idling smoothly until the engine warms up to where it will idle fine on its own. You shouldn't need the flame heater for longer than 30 seconds once the engine catches and starts to run.

 

[OldDominionIron]

If you have never used your flame heater before, or it's been a while, check it for leakage after you've finished using it. The O-rings inside it can dry out and leak when exposed to the higher pressure of the IP. If you break the injector for any reason (such as over-tightening the locknut, not that I'd confess to doing that) Clark Truck Parts has used ones for $45. There is a little disassembly involved in replacing one (I mean, if I actually had to replace one after breaking it)

 

[cranetruck]

If you have any old Military Vehicles Magazines around, look for the October 2003 issue (#99)... article by yours truly on the flame heater operation, test and verification of function.

Use it sparingly, as stated above, it uses up oxygen.

 

[Orionspath]

Great topic considering the deep penetrating freeze in the last few weeks!

 

[timntrucks]

on my preheater there is a wire burnt off just at the connection.. thinking it would be best to just get a new wire for it.. anyone have thoughts on that ..

 

[Earth]

I'm using a combination of starting aids on the deuce I'm running this winter. Primarily the block heater, 600 watt screw in from westy, but also the flame heater. This flame heater is working fine, and you can hear the little pump and feel the multifuel taking off on the flame. It's an unmistakable and positive addition to the starting experience. On the other hand, I have a dropside deuce that when you flip the flameheater switch absolutely nothing happens. It needs to be serviced and I failed to get to it before the cold. So, I feel that if functioning properly, the flameheater is a good cold weather starting aid. I used it solely down to about 20 degrees and then we started plugging in the block heater. Starting diesels in the winter is war.

 

[Redleg130]

Older thread but closest to my question and there is great info in this thread.

It has been below zero in my area last few weeks, and I was curious about its ability to start in these cold temperatures. Good news is that it does start after a small handful of tries, like 7-10, which I think is fairly normal or acceptable. It did start reliably in any case over the course of a week making attempts every other day or so. On a couple attempts, I tried the flame heater/manifold heater according to the TM - only switching on while being cranked and no longer than 10 seconds. I noticed no difference between switching the heater on vs not using it, so I cant tell if it works.
The engine cranking drowns out any noise the manifold heater would make, and I don't want to switch it on without cranking. Is there any test I can run to determine if this system is working as it should?
The poster "Earth" from 2010 states the manifold heater should produce a noticeable effect while starting. I am unable to find the article from Cranetruck in issue 99 of military vehicles magazine, which I assume is only available in print.

The answer may be I don't need this starting aid as the temperatures we got in the Midwest Jan 2024 are about as bad as they can get, and the truck started reliably. But since this system is in my truck, I would like to have it available in case I may need it sometime, so some way of knowing how to test it would be welcome.

 

[NY Tom]

Older thread but closest to my question and there is great info in this thread.

It has been below zero in my area last few weeks, and I was curious about its ability to start in these cold temperatures. Good news is that it does start after a small handful of tries, like 7-10, which I think is fairly normal or acceptable. It did start reliably in any case over the course of a week making attempts every other day or so. On a couple attempts, I tried the flame heater/manifold heater according to the TM - only switching on while being cranked and no longer than 10 seconds. I noticed no difference between switching the heater on vs not using it, so I cant tell if it works.
The engine cranking drowns out any noise the manifold heater would make, and I don't want to switch it on without cranking. Is there any test I can run to determine if this system is working as it should?
The poster "Earth" from 2010 states the manifold heater should produce a noticeable effect while starting. I am unable to find the article from Cranetruck in issue 99 of military vehicles magazine, which I assume is only available in print.

The answer may be I don't need this starting aid as the temperatures we got in the Midwest Jan 2024 are about as bad as they can get, and the truck started reliably. But since this system is in my truck, I would like to have it available in case I may need it sometime, so some way of knowing how to test it would be welcome.

Might be able to remove the flame heater nozzle from the manifold and activate it without start to see if it is spraying fuel.