Use glow plugs at every start?

[CO2Wrangler]

If anything I would think getting the oil warm and flowing is more of a concern for the EcoD than the glow plugs before a start.

Typically that's why you see a high idle in colder temps. Trying to get the oil flowing sooner. I'm usually watching oil temp and pressure on cold mornings. Try not to get on it until oil temp is a bit over 100.

Not sure if this is a good practice but the oil pressure is so damn high on a cold start it makes me nervous.

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[Camaroboi13]

The days of the old school diesel are gone, we are not trying to warm up glow plugs in a big six liter straight six diesel with a very rudimentary fuel system. Our fuel pressures are ridiculously higher than they used to be, and efficiency makes things work better, easier, and faster.

 

[SargeDiesel]

In Alabama, we get in the low teens. I've have never purposely engaged the glow plugs. I DO always let the engine idle up to an acceptable operating temperature. I also let it cool down to a sub 400° turbo out temperature before shutting it down.

Back in my days of driving 5-tons and HMMWV's... they had a switch to engage the glow plugs and you had to wait for the idiot light to turn off before starting... this was done in any climate.

But on the JT, it has never hesitated or had a rough start due to weather.
If I was really worried about it, I would plug in or use a block heater.

 

[Deleted User 38384]

Stupid question, but why?

To keep it warm, and cool.

 

[BDinTX]

You know… I forgot all about glow plug warm up and whatnot. Was easier to do on my old trucks. I usually only let it warm up for 60-90 seconds before going. Oil temp around 90°. But it is garage kept…. Sorry im just not adding value here

 

[AK66]

For anyone who doesn't know, to get the glow plugs started on our EcoDiesels Wranglers, You need to put the vehicle in run, without the engine on and you'll see that little twisted rope icon pop up on the dash which will let you know that the glow plugs are getting power.

Same happens on my Audi TDI. When the "rope" light turns off, you're good to start. It won't start if you turn the key too soon.
I usually let it idle at least a minute, longer when it gets colder. And then drive like a grandma until the coolant temp needle starts moving, keeping it under 2200-2400 rpm.
The one single thing I hate in diesels. That in cold weather you can idle from start to Christmas and your heater won't get warm before you go ahead and drive it for a while.
I don't own a JL diesel yet (seriously considering), but I believe it behaves similarly in this matter.

 

[Grayhound]

Same happens on my Audi TDI. When the "rope" light turns off, you're good to start. It won't start if you turn the key too soon.
I usually let it idle at least a minute, longer when it gets colder. And then drive like a grandma until the coolant temp needle starts moving, keeping it under 2200-2400 rpm.
The one single thing I hate in diesels. That in cold weather you can idle from start to Christmas and your heater won't get warm before you go ahead and drive it for a while.
I don't own a JL diesel yet (seriously considering), but I believe it behaves similarly in this matter.

I can confirm heater heats when in motion.

I love the cold weather group. Just wish I could set the seat heat trigger at 70 and the wheel at 50.

 

[gsbrockman]

I'm going to tag in some diesel Bros I know see what people think...

@gsbrockman
@Ratbert
@SargeDiesel
@BDinTX
@Irishguy1973
@Tread4Lo

I'm sure there's others, I just can't think of you all off the top of my head.

Well, the only vehicle I’ve ever owned with glow plugs was a 2005 Jeep Liberty CRD Limited. It was a non-issue with it, as it was always garaged. Occasionally….when it was garaged, on planned trips I’d plug up the engine block heater for a couple of hours or so prior to departing.

I’ve owned several (10, actually) RAM / Cummins equipped trucks since 1997. All of those utilize a grid heater (imagine a heating element similar to what you’d see within a toaster) for warming up of the intake air at first crank. The grid heater will then cycle for a period of time until the determination is made that it’s no longer needed, or maybe around 15 mph has been attained.

In any event…..another poster is right…..today’s high pressure common rail diesels aren’t very fickle in regards to cold weather starting.

The high rail pressures atomizes the fuel to such a degree that cold weather starts are a thing of the past, unless one has compromised or untreated fuel.

The times one does see the grid heater or glow plugs cycling on newer vehicles is basically emissions driven; ie a smidgen of hotter intake air, even on a partially warmed up engine, can reduce the emissions down somewhat.

 

[Deleted User 38384]

Well, the only vehicle I’ve ever owned with glow plugs was a 2005 Jeep Liberty CRD Limited. It was a non-issue with it, as it was always garaged. Occasionally….when it was garaged, on planned trips I’d plug up the engine block heater for a couple of hours or so prior to departing.

I’ve owned several (10, actually) RAM / Cummins equipped trucks since 1997. All of those utilize a grid heater (imagine a heating element similar to what you’d see within a toaster) for warming up of the intake air at first crank. The grid heater will then cycle for a period of time until the determination is made that it’s no longer needed, or maybe around 15 mph has been attained.

In any event…..another poster is right…..today’s high pressure common rail diesels aren’t very fickle in regards to cold weather starting.

The high rail pressures atomizes the fuel to such a degree that cold weather starts are a thing of the past, unless one has compromised or untreated fuel.

The times one does see the grid heater or glow plugs cycling on newer vehicles is basically emissions driven; ie a smidgen of hotter intake air, even on a partially warmed up engine, can reduce the emissions down somewhat.

Interesting. That makes me feel better already.

I'm still going to film that video and post here the difference between a cold start without igniting the glow plugs for a few seconds, and a cold start with the glow plugs.

I started it this morning had to run out and get some ice before the family got here, it was like 38 this morning I think, and it is definitely what I would consider a rough start. It had no issue starting, but it cranks for about 2 seconds before it finally started and it ran rough for about 2 minutes till it warmed up a little bit.

Supposedly from what I've read over the last week, that's exactly what the glow plugs help with, make it a smoother start and a smoother warming up process. Less rough idling initially.

 

[Deleted User 38384]

You know it might all be in my head...

First video is without glow plugs to warm up,
Second video is with glow plugs to warm up.






I'll probably record a couple more of these videos as we get into the colder days here in Texas just to get a better understanding and have some documented film footage so that I can go back and listen to it and see if there's any real difference or if I'm just crazy!

Let me know your thoughts, maybe there's something I'm missing?

 

[Deleted User 38384]

In the video below, when I say I've lived in Connecticut most of my life, I mean I'm about to be 38 in a few days here, and I've lived in Connecticut for 20 years, Illinois for 3 years, and Texas for 13 years now.



I'm not sure what activates the glow plugs, but for whatever reason I'll do everything right to start the glow plugs and then the second I push on the break and go for the start button, all the sudden that's when the glow plugs decide they want to preheat.

I'm sure there's an intricate way to make it work every time, but it's definitely not a straightforward as I would think. Maybe the glow plugs had already done their job and when the twin loop light shut off after about half a second when I first put it in engine off/run mode, it meant they were already preheated enough? But then why would it say "Preheating Engine Wait To Start" after it's been in run mode for about 2 minutes and only does it once I go to actually start the vehicle?

Maybe I'm not activating glow plugs properly? I guess I should probably look up in the manual and see how to actually activate the glow plugs. Maybe there's some brake pedal involvement or something which I'm missing.

 

[BDinTX]

Good luck, I wasn’t able to find it in the manual. This is the best I could come up with:

 

[Ratbert]

Good luck, I wasn’t able to find it in the manual. This is the best I could come up with:

It's almost like we they've designed it explicitly so we don't have think about it?

 

[jav_eee]

For anyone who doesn't know, to get the glow plugs started on our EcoDiesels Wranglers, You need to put the vehicle in run, without the engine on and you'll see that little twisted rope icon pop up on the dash which will let you know that the glow plugs are getting power.

you don’t need to do any of the this. The glow plug activation that happens when you start the vehicle is more than enough. Modern day for 6.7s start almost instantly after the button press. These aren’t the glow plug systems of the “wait to start” years.

 

[driventoadventure]

Don't forget that Cummins' have a grid heater which heats the inlet air, not glow plugs heating the cylinder volume.

The purpose of the glow plugs isn't to heat the cylinders, it's to ensure that the air isn't cold enough to inhibit complete combustion. It's not that your engine will fail to start without the preheating capability, but that it won't run effectively - IE it will be extremely rough, misfire, and generally just not run well. It's not until your temps get well into the negative temperatures that they will actually keep the engine from running all together...

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