# Does not "glowing" the plugs lead to CEL's



## au201 (May 18, 2013)

In my completely non-expert opinion, it probably wouldn't cause any issues the cars computer can't take care of. However, it's simply not a good practice. The glow plugs in the Cruze, as I understand it, are very quick to warm up. It just takes a second. And when you remote start, the computer waits for the glow plugs by itself, so you don't have to worry about it there. 


Sent from AutoGuide.com Free App


----------



## diesel (Jun 8, 2013)

I always glow mine, but I got used to doing that having older diesels. it's always extremely quick, even in winter. I heard somewhere that the glowing process actually starts when you open the driver's door, but i have no proof of that. Mostly, the car was designed so that people don't have to think about that.


----------



## oldestof11 (Apr 3, 2016)

When it's warm out, above 50*ish, that glow plug light is doing a light check. With modern direct injection and multi-event injector pulse control, it doesn't need glow plugs.


----------



## Tomko (Jun 1, 2013)

diesel said:


> I always glow mine, but I got used to doing that having older diesels. it's always extremely quick, even in winter. I heard somewhere that the glowing process actually starts when you open the driver's door, but i have no proof of that. Mostly, the car was designed so that people don't have to think about that.


I know that it doesn't on mine:

One winter morning my wife forgot herself and just engaged the starter, without pausing for the glowplugs. The engine cranked and cranked on its own and eventually started. But would have started within three power strokes had the glowplugs been used.


----------



## MP81 (Jul 20, 2015)

We always wait for the glow-plug light to go out, as it says in the manual, before starting.

As mentioned above - it takes a few more cranking cycles to start when its cold out, if you don't wait for them.


----------



## IndyDiesel (May 24, 2015)

I always wait, but after the car is hot mine doesn't come on or the light doesn't come on for plugs. With the battery a weak link on these cars and pricey to replace why would you want to crank longer than necessary?:uhh:


----------



## Chris Tobin (Feb 23, 2016)

I wait on the glow plug light to shut off, but on the CTD it shuts off very quickly in most circumstances. In our VW TDIs it seems to be a simple timer and runs them a set amount of time after each time you turn the key on, while the Cruze Diesel seems to be intelligent and only turns them on as long as needed since they draw a lot of current too.


----------



## MilTownSHO (Oct 9, 2013)

IndyDiesel said:


> With the battery a weak link on these cars and pricey to replace why would you want to crank longer than necessary?:uhh:


I keep reading that but mine is still going strong on the original, almost 3 years and 77k miles.

Back to the OP's point though, I have once or twice forgotten. It always starts, just takes a little longer and is rough for a minute.

With how quick the glow plugs are in this car, I don't see why you wouldn't just wait as it's designed.


----------



## Aussie (Sep 16, 2012)

I live in a mild climate in Sydney Australia and apart from the check at start up I haven't seen the glow plug light come on at all. The car is now 4 years old and the coldest it has seen is 2C (about 39F). It has always started without effort and is still on the original battery.


----------



## spacedout (Dec 7, 2010)

mkohan said:


> Who starts without waiting for the glow plug light to go out? What happens if you just jump in the diesel and fire it up? Is there more soot produced during start up and possible senor fowling? I'm just starting to learn about diesels and don't have a clue as to the answers.


It would be best to try to understand why a diesel uses glow plugs then you will see their importance. Unlike a gas engine that uses spark plugs to ignite the fuel a diesel uses compression and heat only.; With a cold engine part of that equation is missing, this is where the glow plug comes in. Its job is to add enough heat for the combustion process to start. Sure on hot days this may be less necessary but as you asked above could this lead to more soot or sensor fowling? I would think so since without that heat there is more chance for the fuel to not be burned completely. 

I've just got in the habit to always wait for the light to go out on any diesel before i attempt to start.


----------



## pandrad61 (Jul 8, 2015)

I use remote start and i hear it prime, and i assume glow plugs get hot then when its ready it fires up. When i get in the car i turn key to ready and wait for the electric fuel pump noise to stop and by that time all dash lights are off and i fire it up...takes 3 seconds or so


----------



## pavulon (Aug 23, 2016)

As a new owner anticipating deeply cold (-25F) winter situations, is there any advantage to waiting extra time for cylinder heating? Will the plugs cycle more than once?


----------



## pandrad61 (Jul 8, 2015)

> As a new owner anticipating deeply cold (-25F) winter situations, is there any advantage to waiting extra time for cylinder heating? Will the plugs cycle more than once?


i dont think so. with diesel big rigs you have a switch to keep them on for longer if needed and newer ones keep light on untill ready.... i think cruze is pre set...don't know for sure


----------



## au201 (May 18, 2013)

pavulon said:


> As a new owner anticipating deeply cold (-25F) winter situations, is there any advantage to waiting extra time for cylinder heating? Will the plugs cycle more than once?


I believe they will only come on once per key cycle and the duration they're on will depend on outside temperature. It should only require one cycle. However, if it has trouble starting, a few more cycles wouldn't hurt. 


Sent from AutoGuide.com Free App


----------



## diesel (Jun 8, 2013)

pavulon said:


> As a new owner anticipating deeply cold (-25F) winter situations, is there any advantage to waiting extra time for cylinder heating? Will the plugs cycle more than once?


No need to worry about it, assuming your fuel is properly winterized. Here is my car in -9F with fuel that wasn't quite up to the job. There are a few other vids on Youtube.

https://www.youtube.com/watch?v=KTUmnLrMGL8


----------



## boraz (Aug 29, 2013)

pavulon said:


> As a new owner anticipating deeply cold (-25F) winter situations, is there any advantage to waiting extra time for cylinder heating? Will the plugs cycle more than once?


-51 here

wait for the light to go out,car starts normal


----------



## boraz (Aug 29, 2013)

pandrad61 said:


> i dont think so. with diesel big rigs you have a switch to keep them on for longer if needed and newer ones keep light on untill ready.... i think cruze is pre set...don't know for sure


never seen such a switch


----------



## Aussie (Sep 16, 2012)

boraz said:


> never seen such a switch


It works off the ignition key.


----------



## boraz (Aug 29, 2013)

Aussie said:


> It works off the ignition key.


was refering to the switches in big rigs he's talkin aboot


----------



## oldestof11 (Apr 3, 2016)

spacedout said:


> It would be best to try to understand why a diesel uses glow plugs then you will see their importance. Unlike a gas engine that uses spark plugs to ignite the fuel a diesel uses compression and heat only.; With a cold engine part of that equation is missing, this is where the glow plug comes in. Its job is to add enough heat for the combustion process to start. Sure on hot days this may be less necessary but as you asked above could this lead to more soot or sensor fowling? I would think so since without that heat there is more chance for the fuel to not be burned completely.
> 
> I've just got in the habit to always wait for the light to go out on any diesel before i attempt to start.


Glow plugs aid in cold start emissions anymore. The compression and the fuel droplet size of current diesels all but negate the need for glow plugs short of cold temps. 

See Cummins 6BT and ISB engines. No glow plugs.


----------



## boraz (Aug 29, 2013)

oldestof11 said:


> Glow plugs aid in cold start emissions anymore. The compression and the fuel droplet size of current diesels all but negate the need for glow plugs short of cold temps.
> 
> See Cummins 6BT and ISB engines. No glow plugs.


do they have intake heaters?


----------



## justin13703 (May 2, 2016)

I've always been in the habit with any car I drive, diesel or not, to turn the key to ignition, let it sit for a few seconds, and then start it. I never get in a car and put the key in and instantly slam it all the way to start. This gives the glow plugs plenty of time to warm up in cold weather. I guess this habit came from driving older stuff like my jeep that you had to let the fuel pump prime everything for a few seconds before you crank it.


----------



## oldestof11 (Apr 3, 2016)

boraz said:


> do they have intake heaters?


Strictly to reduce cold start smoke. It helps but not intended to be a cold start aid.


----------



## justin13703 (May 2, 2016)

oldestof11 said:


> boraz said:
> 
> 
> > do they have intake heaters?
> ...


That's strange. The Cummins we have at work has an intake grid heater. It explicitly states to wait until the grid heater light goes out to aid with cold weather starting. It even says that in very cold weather you can cycle the heater twice before starting. Anything that warms the air going into a Diesel engine for a cold start is going to help it start, whether it's a grid heater, glow plugs, or a block heater.


----------



## oldestof11 (Apr 3, 2016)

justin13703 said:


> That's strange. The Cummins we have at work has an intake grid heater. It explicitly states to wait until the grid heater light goes out to aid with cold weather starting. It even says that in very cold weather you can cycle the heater twice before starting. Anything that warms the air going into a Diesel engine for a cold start is going to help it start, whether it's a grid heater, glow plugs, or a block heater.


Yes. I thought that too. 

When I brought it up in an argument, a good friend of mine showed me literature from Cummins. He teaches diesel mechanics at a Pennsylvanian college. You can remove the intake heater and it'll still start. It aids in warming the air to help reduce white smoke on startup. 

Also from personal experience, I've had a 12v VE Cummins without a working grid heater start in -10*. I lived in an apartment at the time and had no problems getting it started. 1 battery, 2 tries, lots of white smoke. 

Now compare the ignite-ability of the fuel droplet in an injector needing 3600psi to open and our modern systems which can see 20,000psi and push the same fuel BTDC, TDC, and ATDC. Then the difference in 6 holes .009" in diameter and whatever the Cruze may use.


----------



## mkohan (Dec 19, 2015)

So, I'm hearing that modern diesels will start without using glow plugs...they might smoke but will start. Does the smoke affect the sensors is the question. The sample size of this tread is small but it seems that most of the Cruze owners that regularly use the glow plugs are having less CEL trouble.


----------



## Cruzator (Dec 31, 2014)

I have a Cummins ISB in a Dodge. Yes, it will start when it's cold (down to around zero) without the intake grid heater being warmed, but it doesn't like it. Coughs and belches smoke for 5 -10 seconds. With the heater it might miss for a second or two. It also cycles on and off for up to two minutes or so, to reduce cold start smoke. I have no idea if the glow plugs on the CTD cycle after they start. On the Cummins, it's obvious when they kick on and off - both by the drop in the voltmeter, and the dimming of the headlights, or slowing of the heater blower. I know a lot of people with powerstrokes that have to cycle them a few times when it's very cold (also at high altitude). My CTD has never shown any indication of not starting when paying attention to the glow plug wait indicator light. I don't think I"ve ever had it stay on more that 5 secondsw (when it's well below zero).


----------

