Glow plugs? No Codes-starts rough.

[camping-guy]

I have an '05 LLY that is getting tougher to start in the cold. Overnight temps in the teens to low 20's. I normally plug it in about this time of year, but haven't yet. The last couple of mornings, glow plug light lights up about normal amount of time, but engine cranks longer [fast cranking, new batteries last spring]. Will fire once and kicks out the starter but dies. Usually the second time it will fire up, running on just one or two cylinders for a few seconds, and within about 30 seconds smooths out. During this time the exhaust smells very rich.

I think it is getting plenty of fuel based on how rich it runs at first, and cranks pretty fast, so I am thinking glow plugs, but I am not getting any codes. Elsewhere in the forums, it looks like if I don't get codes I shouldn't replace the glow plugs, that it might be something else.

Any ideas for me?

Thanks for any direction you can give me.

[DieselLuver]

Plug it in..?

[camping-guy]

Originally Posted by DieselLuver

Plug it in..?

I plug in the block heater as it gets colder, have a circuit on a timer so it's good to go when I need to leave for work. I don't mind plugging it in when I can, but if it sits out for a few hours at work in near zero [or below] temps this winter, I will need it to start even when I can't plug it in.

Looking for feedback as to whether I should replace the glow plugs, or look for something else going on.

[camping-guy]

Just wanted to add this:

I had the block heater plugged in overnight, and is started great! I'm thinking this eliminates almost everything but the glow plugs functioning right.

I guess my question is, without any codes present, is replacing glow plugs the right next step? If the controller was bad, would that for sure set a code? Just don't want to wast money on plugs if that isn't the answer.

[MTL_Dmax]

Originally Posted by camping-guy

Just wanted to add this:

I had the block heater plugged in overnight, and is started great! I'm thinking this eliminates almost everything but the glow plugs functioning right.

I guess my question is, without any codes present, is replacing glow plugs the right next step? If the controller was bad, would that for sure set a code? Just don't want to wast money on plugs if that isn't the answer.

Yes, you'll find codes in the ECM for bad glow plugs or a bad controller if either of those are the issue.......pull your codes for sure.

Mine will start rough without being plugged in too but I also know I have 3 bad glow plugs (there are codes stored for all of them).

[DieselLuver]

Since nobody else is chipping in, to me it dosent sound like you have a problem. All diesels as it gets colder will do the same thing. When it's as cold as its been lately (-35C), i plug it in all night and during the day while I'm working I try to run it every little while so it's not ice cold.

[duratothemax]

Originally Posted by DieselLuver

Since nobody else is chipping in, to me it dosent sound like you have a problem. All diesels as it gets colder will do the same thing. When it's as cold as its been lately (-35C), i plug it in all night and during the day while I'm working I try to run it every little while so it's not ice cold.

yeah but you should still be able to start a duramax without being plugged in when its cold out, even at -30*.

If your duramax wont start without being plugged in when its well below 0* F, then you probably have glow plugs that are going bad..

Ben

[camping-guy]

Originally Posted by DieselLuver

Since nobody else is chipping in, to me it dosent sound like you have a problem. All diesels as it gets colder will do the same thing. When it's as cold as its been lately (-35C), i plug it in all night and during the day while I'm working I try to run it every little while so it's not ice cold.

This is my 5th winter with this truck. This is not normal for it, that is why I am concerned. Don't want to be stranded when it really gets cold!

MTL- Not getting any codes, that's the thing . . .

duratothemax - I agree I need to be able to start it without plugging it in when its cold. Is your suggestion to replace the glow plugs even without any codes set?

I haven't tested any of them yet, if I understand it right, should only have about 1 ohm of resistance if they are OK, and if they are bad they would be showing open, or high resistance?

[MTL_Dmax]

Originally Posted by camping-guy

This is my 5th winter with this truck. This is not normal for it, that is why I am concerned. Don't want to be stranded when it really gets cold!

MTL- Not getting any codes, that's the thing . . .

duratothemax - I agree I need to be able to start it without plugging it in when its cold. Is your suggestion to replace the glow plugs even without any codes set?

I haven't tested any of them yet, if I understand it right, should only have about 1 ohm of resistance if they are OK, and if they are bad they would be showing open, or high resistance?

No codes at all makes me think you should also be checking fuel pressure while cranking too (other issues like ice in fuel, loss prime, etc).

Yes, they should all have a very low resistance (less than 1 ohm) between the terminal and the GP body.

[DieselDog05]

Originally Posted by camping-guy

This is my 5th winter with this truck. This is not normal for it, that is why I am concerned. Don't want to be stranded when it really gets cold!

MTL- Not getting any codes, that's the thing . . .

duratothemax - I agree I need to be able to start it without plugging it in when its cold. Is your suggestion to replace the glow plugs even without any codes set?

I haven't tested any of them yet, if I understand it right, should only have about 1 ohm of resistance if they are OK, and if they are bad they would be showing open, or high resistance?

I was having the same issue with mine , found that the fuse for the fuel heater was blown , explaines why mine started really hard last winter. I replaced the fuse and no issues this winter yet.