truck needs glowplugs even when warm???

[kapnklug]

Used to be, my M1009 would start right up after it had been warmed up, without using the glowplugs (fortunately I've got them on a button). Recently though, it began to need a few seconds of glowplugs even if I'd just shut it off. And now it's getting worse, takes about 10sec of glowplugs even if it's been off for only a minute or so.
What's going on here? Is this an injector problem?
The glowplugs are new AC60G and are on a pushbutton.

 

[USAWEAPON777]

yes that is odd if the weather hasn't changed much. I know if my m1008 is out on a hot day even if its sat all day it will cycle the glow plugs only a second or two to start. However, if its cold that light will be on a mighty long time. I wonder what tells the glowplug system how hot the block is. Maybe that is malfunctioning.

 

[Hasdrubal]

Had a similar issue, all of a sudden I had to use the glow plugs all the time after only stopping for a short while. Turned out that the thermostat had failed, of course its more apparent in colder weather when you notice your heater doesn't blow hot air.

 

[Matt65]

Used to be, my M1009 would start right up after it had been warmed up, without using the glowplugs (fortunately I've got them on a button). Recently though, it began to need a few seconds of glowplugs even if I'd just shut it off. And now it's getting worse, takes about 10sec of glowplugs even if it's been off for only a minute or so.
What's going on here? Is this an injector problem?
The glowplugs are new AC60G and are on a pushbutton.

If the engine is warm - in my experience it should need no GP to fire. Can you confirm that it's the GP cycle that it needs to light, or just additional starting time.
Try a short 2-3 second crank, then wait, then crank till it starts. This is the sequence I used before my IP rebuild. If this ends up being the case, you may want to confirm fuel system. i.e. There may be air in the system that prevents quick starting. The additional cranking time becomes needed because the mech lift pump is re-building it's prime to each cylinder. Keep in mind since the lift pump pulls instead of pushing you could be getting air in the system, but not see diesel leaking.
You may want to check:
- The engine valley for wetness from diesel.
- The IP return check valve could also be sticking open and allowing prime to be lost when shut down.
- Check for leaks at your filter housing, especially if it’s the factory square style. I have seen these leak on several trucks.

 

[cucv1833]

I wonder what tells the glowplug system how hot the block is. Maybe that is malfunctioning.

I beleive thats the temp sensor on the driver side rear block that your talking about. but he has it in a push button so it shouldnt matter. I have mine bypassed on a push button i give it some glow when i first start it and thats it. I can let it sit for 3-4 hrs in this hot weather and it will start back up with no glow.

 

[Barrman]

The stock glow plug system is supposed to come on if the engine temp is below 125°. I "think" the WAIT light comes on if the engine is below 85°. Or at least those were the thoughts of the designers 30 years ago. What is actually happening with your engine depends on the state of the glow plugs, the temp sensor, the GP card and or your push button mod.

 

[Screamin' Metal]

Correct! Wait to start is after the glowplugs have initialized, and will turn off after the timer has tripped. If you listen for that thud, its the controller kicking out, you can start the truck.
After a truck has been run some, it should start really easy within 30 to 45 minutes. A diesel has no sparkplugs, it gets its ignition from the heat being compressed in the cylinders. If everything is in good working order, your truck should start within a second or two. IF IT DOESN'T THERES A PROBLEM!
Remember......usually the glowplugs will start failing one by one. One a cold engine, you need them. On a warm engine, you need them. On a hot engine, no you do not. Remember the old pony motors on the heavy equipment? If anyones ever been around one of the old cats, it'll start running 1 cylinder at a time until all of them are running. Thats what glow plugs do for you now. And a good strong electric starter with good batteries........
Some of the old dozers, its a 30 minute starting ritual to get those running, You had to get the pony motor running, then you'd pull the air cleaner on the diesel intake, a 5 second burst of ether into the intake tract, pull the engagement lever to throw in the pony motor to spin it over, grab your can of ether, as it spun you'd give it a short spray till it started, then let her run till all cylinders were firing, then disengage the pony. Fun oh fun!!!!!!!!!!!!!!!!!!!!!!