# How do I check glow plug functioning?



## Barry Allen (Apr 18, 2018)

How can I check to make sure all glow plugs in an engine are functioning properly? Does the ECU display any error messages?

Yesterday (during the polar vortex) it was -20°F when I started my car to leave from work. The starter engaged for a good 3-4 seconds and then the starter continued to crank for another 10 seconds while the engine seemed to be "misfiring." It was chugging like only one or two cylinders were initially firing and it eventually caught and ran with only one or two other "misfires" in the next 20 seconds of running. Obviously it was running loud with a lot of clatter in the cold weather.

For a car that others on this message board say starts fine down to -40°F this gave me the impression that it was really struggling to start. Another 5-10 degrees colder and I believe it might not have started at all.


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## Robby (Mar 1, 2013)

The ecu will display a check engine light.
A code reader will show a glow plug code and going further into the menu it will then tell you which glow plug has created the code. I might add I am using a Tech II for this diagnosis.......a fairly generic failure that does not require use of the GM Global diagnostic system.
It will also test resistance and ohms and report accordingly.

I have to address two or three glow plug failures a year on our three company Duramax's.......all over two hundred k.
No rhyme or reason......they just go open.......same as any other electric heating device.



There is no specific glow plug failure beyond the cel illuminated.

Rob


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## MRO1791 (Sep 2, 2016)

Barry Allen said:


> How can I check to make sure all glow plugs in an engine are functioning properly? Does the ECU display any error messages?
> 
> Yesterday (during the polar vortex) it was -20°F when I started my car to leave from work. The starter engaged for a good 3-4 seconds and then the starter continued to crank for another 10 seconds while the engine seemed to be "misfiring." It was chugging like only one or two cylinders were initially firing and it eventually caught and ran with only one or two other "misfires" in the next 20 seconds of running. Obviously it was running loud with a lot of clatter in the cold weather.
> 
> For a car that others on this message board say starts fine down to -40°F this gave me the impression that it was really struggling to start. Another 5-10 degrees colder and I believe it might not have started at all.


I believe the extra cold guys are Gen 1, not Gen 2. The 2.0l TD has a higher compression ratio. That would be beneficial in cold start. Gen 2 really needs glow plugs for the extra cold start with it's lower compression ratio. I'm not sure of many extra cold Gen 2 people out there. 

Sent from my Moto G (4) using Tapatalk


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## Ma v e n (Oct 8, 2018)

Yes the ECM monitors the glow plugs and the glow plug controller. The ECM sets DTCs related to glow plug function. If there's a glow plug function issue, it'll set a code. There's only four glow plugs, and like 15 DTC the ECM monitors conditions for


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## TDCruze (Sep 26, 2014)

MRO1791 said:


> I believe the extra cold guys are Gen 1, not Gen 2. The 2.0l TD has a higher compression ratio. That would be beneficial in cold start. Gen 2 really needs glow plugs for the extra cold start with it's lower compression ratio. I'm not sure of many extra cold Gen 2 people out there.
> 
> Sent from my Moto G (4) using Tapatalk


This is my first winter with the Gen 2 had four winters on the Gen 1. 
I pretty much always plug my cars in when its cold. Really can't say much for a true cold start. 

I have found the Gen 2 to start a bit easier/smoother than the Gen 1 diesel. 

The Gen 1 below -10F or so would crank slower like the battery was weak, even from new. 
A few times I didn't think it would start when below -20F or so. 
If not plugged in I could only imagine it may not have started? 
Also, the engine seemed to stumble/miss and run rougher at these temps once first started.


Even the cabin heat output seems better in the Gen 2, I have not had a cover on the grille and the car warms up much faster. 
Without the grille covered on the Gen 1 below -10F and the car took forever to warm the cabin. 

Part of it may be the Gen 2 cranks over easier/faster with the larger capacity battery thanks to the AS/S system (auto only)
Not sure if the manual trans Gen 2 have the same battery as the auto trans cars? 
Maybe, hotter glow plugs, different injectors or head design?


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## MRO1791 (Sep 2, 2016)

TDCruze said:


> Part of it may be the Gen 2 cranks over easier/faster with the larger capacity battery thanks to the AS/S system (auto only)
> Not sure if the manual trans Gen 2 have the same battery as the auto trans cars?
> Maybe, hotter glow plugs, different injectors or head design?


Same battery in manual as auto for Gen 2 Diesel. I have both. A lower compression ratio makes for an easier to turnover engine, but less compression heat, and thus a need for more glow plug heat.


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## MRO1791 (Sep 2, 2016)

TDCruze said:


> This is my first winter with the Gen 2 had four winters on the Gen 1.
> I pretty much always plug my cars in when its cold. Really can't say much for a true cold start.
> 
> I have found the Gen 2 to start a bit easier/smoother than the Gen 1 diesel.
> ...


Interesting observations. The Gen 1 had quite a few week original batteries from production, and I think the AGM under the hood suffers higher temperatures than it should have. It appears both those issues solved in Gen 2. For the better heat, yes, it's noticiable, and you can thank the all Aluminum engine block in Gen 2, over the cast iron engine block on the Gen 1 for the faster cabin heat. That said, the Gen 1 had the electric boost for the issue, which helped a bit I suppose.


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## TDCruze (Sep 26, 2014)

Barry Allen said:


> How can I check to make sure all glow plugs in an engine are functioning properly? Does the ECU display any error messages?
> 
> Yesterday (during the polar vortex) it was -20°F when I started my car to leave from work. The starter engaged for a good 3-4 seconds and then the starter continued to crank for another 10 seconds while the engine seemed to be "misfiring." It was chugging like only one or two cylinders were initially firing and it eventually caught and ran with only one or two other "misfires" in the next 20 seconds of running. Obviously it was running loud with a lot of clatter in the cold weather.
> 
> For a car that others on this message board say starts fine down to -40°F this gave me the impression that it was really struggling to start. Another 5-10 degrees colder and I believe it might not have started at all.


It is possible that your fuel had begun to gel a bit and was not being sprayed properly through the injectors causing a hard start. 
Not being plugged in does not help this. 



MRO1791 said:


> Interesting observations. The Gen 1 had quite a few week original batteries from production, and I think the AGM under the hood suffers higher temperatures than it should have. It appears both those issues solved in Gen 2. For the better heat, yes, it's noticiable, and you can thank the all Aluminum engine block in Gen 2, over the cast iron engine block on the Gen 1 for the faster cabin heat. That said, the Gen 1 had the electric boost for the issue, which helped a bit I suppose.


I never found the aux. electric heat helped much below 20F or so, couldn't really feel it anymore anyways.


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## Barry Allen (Apr 18, 2018)

MRO1791 said:


> The 2.0l TD has a higher compression ratio. That would be beneficial in cold start.


It wouldn't kill anyone at GM to give us an 18:1 compression ratio or a bit higher. I know the 16:1 ratio is both for emissions and for NVH reduction (less ignition clatter) but it doesn't help efficiency and it makes cold starts harder.


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> Even the cabin heat output seems better in the Gen 2, I have not had a cover on the grille and the car warms up much faster.
> Without the grille covered on the Gen 1 below -10F and the car took forever to warm the cabin.


I think all the Gen2 cars have those active shutters that close off the front grill when extra cooling isn't needed. That certainly helps with cabin heat.


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> It is possible that your fuel had begun to gel a bit and was not being sprayed properly through the injectors causing a hard start.


That would not surprise me. My fuel source is a major commercial fuel station with a B11 blend. It's for fleet customers and I always see nothing but semi tractors fueling there without any notable issues in winter so when I set up an account with them I assumed their winter treatment is robust enough. 

However, this polar vortex is one of the worst I've experienced in my life. At -20°F with a -45°F wind chill, it was obscenely cold. It was so cold that things hurt everywhere. I know the wind chill doesn't affect inanimate objects other than accelerating heat loss, but it wouldn't surprise me if -20°F was right on the edge of fuel gelling.

I've got video of the hard start. I should upload it to YouTube and post here if anyone is interested.


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## TDCruze (Sep 26, 2014)

Barry Allen said:


> I think all the Gen2 cars have those active shutters that close off the front grill when extra cooling isn't needed. That certainly helps with cabin heat.


The Gen 1 diesel has the shutters as well, on both versions they only cover the lower grille. 
I almost completely blocked the top grille opening off on the Gen 1 to get it to warm up faster in very cold weather. 
Otherwise it did not put out heat for quite a while and would cool off quickly in town.


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## Robby (Mar 1, 2013)

Barry Allen said:


> That would not surprise me. My fuel source is a major commercial fuel station with a B11 blend. It's for fleet customers and I always see nothing but semi tractors fueling there without any notable issues in winter so when I set up an account with them I assumed their winter treatment is robust enough.
> 
> However, this polar vortex is one of the worst I've experienced in my life. At -20°F with a -45°F wind chill, it was obscenely cold. It was so cold that things hurt everywhere. I know the wind chill doesn't affect inanimate objects other than accelerating heat loss, but it wouldn't surprise me if -20°F was right on the edge of fuel gelling.
> 
> I've got video of the hard start. I should upload it to YouTube and post here if anyone is interested.



Agree on the weather.....here in DesPlaines I started Wednesday morning showing -25 and this Thursday (today) showing -20.
I reflect back to winter 1985 here.....-26.....a record still standing.

House makes cracking noises all night......car sounds like it is made of glass over the first few bumps.

A true character builder, eh?

Rob


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## TDCruze (Sep 26, 2014)

Barry Allen said:


> That would not surprise me. My fuel source is a major commercial fuel station with a B11 blend. It's for fleet customers and I always see nothing but semi tractors fueling there without any notable issues in winter so when I set up an account with them I assumed their winter treatment is robust enough.
> 
> However, this polar vortex is one of the worst I've experienced in my life. At -20°F with a -45°F wind chill, it was obscenely cold. It was so cold that things hurt everywhere. I know the wind chill doesn't affect inanimate objects other than accelerating heat loss, but it wouldn't surprise me if -20°F was right on the edge of fuel gelling.
> 
> I've got video of the hard start. I should upload it to YouTube and post here if anyone is interested.


Be interested in seeing the video. 

Definitely worth running an additive before such weather. Or find some #1 diesel.


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## jblackburn (Apr 14, 2012)

Barry Allen said:


> I think all the Gen2 cars have those active shutters that close off the front grill when extra cooling isn't needed. That certainly helps with cabin heat.


No shutters. They were deemed unnecessary. 

Aluminum block (diesel too) and water cooled exhaust manifold (not sure on diesel, don't see it mentioned) help the 1.4 make heat nearly 5x as quick as the old one. 

Sent from my SM-G950U using Tapatalk


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> Definitely worth running an additive before such weather. Or find some #1 diesel.


Look, I was trying to get two days off work. I'd rather just stay home with the "My car won't start" excuse.

There is no #1 diesel anywhere near me that I'm aware of. It just doesn't exist this far south. There are some K-1 kerosene pumps in town but that's still too much sulphur in the fuel to be used in my car unless/until I get a DPF delete.


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## Barry Allen (Apr 18, 2018)




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## Barry Allen (Apr 18, 2018)

Robby said:


> A true character builder, eh?


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## TDCruze (Sep 26, 2014)

Barry Allen said:


> Look, I was trying to get two days off work. I'd rather just stay home with the "My car won't start" excuse.
> 
> There is no #1 diesel anywhere near me that I'm aware of. It just doesn't exist this far south. There are some K-1 kerosene pumps in town but that's still too much sulphur in the fuel to be used in my car unless/until I get a DPF delete.


Had an old guy at work, now retired. He used to just phone in on these real cold days and say the dog unplugged his truck. 
Was a '98 F-350 7.3L diesel. Doubt he even tried to start it! :lol:



jblackburn said:


> No shutters. They were deemed unnecessary.
> 
> Aluminum block (diesel too) and water cooled exhaust manifold (not sure on diesel, don't see it mentioned) help the 1.4 make heat nearly 5x as quick as the old one.
> 
> Sent from my SM-G950U using Tapatalk


The Gen 2 diesel still has the lower grille shutters. 

Not sure about the exhaust manifold, can't really see it. The turbo bearings are water cooled though.


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> Had an old guy at work, now retired. He used to just phone in on these real cold days and say the dog unplugged his truck.
> Was a '98 F-350 7.3L diesel. Doubt he even tried to start it! :lol:


There were no 1998 F-350 pickups. Production of the ninth generation F-series ended in 1997 and then 1998 production of Super Duty models skipped to 1999 model year.


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## MRO1791 (Sep 2, 2016)

Barry Allen said:


> It wouldn't kill anyone at GM to give us an 18:1 compression ratio or a bit higher. I know the 16:1 ratio is both for emissions and for NVH reduction (less ignition clatter) but it doesn't help efficiency and it makes cold starts harder.


The emissions are driving this, and higher compression needs more EGR, and that has proven to be problematic. The trend is lower diesel compression ratios, and it ironically higher gasoline engine ratios.. actually they are now darn close. Mazda has an even lower compression diesel design, the goal being in chamber NOx reduction with out use of EGR, the limiting factor on lower compression is cold start, so it becomes more dependent on glow plugs... the Mazda design even recircs exhaust via keeping partial open exhaust valves to assist cold start warm up. I don't think we'll see any future Diesel on road engines with higher compression ratios. 

Sent from my Moto G (4) using Tapatalk


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> 7.3L diesel


A guy I used to work for owned a 1988 Ford with the IH 6.9 IDI, and then a 1996 F-250 with the Navistar 7.3 PowerStroke engine. 

Both of his trucks started fine on most days but he was religious at plugging in a block heater for any temperatures below freezing. It just made starting unbelievably easy and brought cabin heat first thing when leaving his house.

For really cold days he had ether injection on both trucks, combined with a glow plug disable switch. During the one or two very cold snaps a year it was easier to just disable the glow plugs with the flip of a switch, put one or two puffs of ether into the intake, and it started right up without any effort or hesitation.


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## Barry Allen (Apr 18, 2018)

MRO1791 said:


> Mazda design even recircs exhaust via keeping partial open exhaust valves to assist cold start warm up


That is something I always expected was coming with variable valve timing being an option on engines. Instead of having a complicated EGR system where it has to be cooled and then can cause trouble by gunking up intake manifolds, why not have a system where the exhaust valve stays open into the intake stroke to draw some of that exhaust back into the cylinder for the next combustion event?

But high temperatures increases NOx, so that's a problem. That's why I think all diesel engines now have cooled EGR where the exhaust recirculation goes through a heat exchanger to dump heat into the cooling circuit. It's got to be cooled to keep NOx production down.


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## TDCruze (Sep 26, 2014)

Barry Allen said:


> There were no 1998 F-350 pickups. Production of the ninth generation F-series ended in 1997 and then 1998 production of Super Duty models skipped to 1999 model year.


Maybe it was a 250? Or a 1996? I am not 100% sure, it was a full size ford truck with the 7.3L diesel from the 90's...

Finally just watched your cold start video. That is a really hard start!!!
I have never had mine struggle at all to start compared to that with good cold rated fuel and the tiny engine heater plugged in.


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## Barry Allen (Apr 18, 2018)

TDCruze said:


> I have never had mine struggle at all to start compared to that with good cold rated fuel and the tiny engine heater plugged in.


I was flirting with disaster. I'm an experimental kind of person so I went into this knowing my fuel source was a B11 blend and I didn't put any additives in the tank, and I don't have the optional oil pan heater (because I don't have anywhere to plug it in). My work would have been flexible and not had a problem with me being a half hour tardy or so if I had to call an Uber.

This was one of those "Once in a decade" weather events. It was January 2009 when the temperature was -22°F so this is almost as low a temperature but much more wind (wind chill). As someone else above described, the fuel in the injectors was gelling up and the spray pattern was probably clogs and globs of fuel spurting out for a few seconds until some heat from compression thawed out the very tips of the injectors. Once it got a very rough spray pattern going the engine would run at idle and it took at least another 30 seconds to run normally (but with a lot more noise than usual).

I'm convinced that about 5°F lower and the car wouldn't have started at all.


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## Barry Allen (Apr 18, 2018)

MRO1791 said:


> Mazda... diesel


As a totally unrelated side note: I'm sick and damned tired of waiting for that Mazda diesel engine, along with other auto makers who teased the idea and then never delivered. 

I was a Subaru owner and somehow got on their mailing list for the quarterly "Drive" magazine when I had some dealership service. I still have my copy of the Fall 2008 magazine where a teaser article showed the Subaru diesel engine built for the European market along with words explaining the engine was "coming soon" to the US market. I spent several years returning to that dealership explaining that I was holding on to my 1991 Legacy until they delivered a diesel sedan. It never arrived. After about 380,000 miles the Legacy was being devoured with rust and had to be retired.

Meanwhile, Mazda had started teasing their diesel engine sometime about 2012. I went to the Mazda dealership and explained I would buy a Mazda 6 sedan when that diesel engine arrived. I got on their email list and the dealership was perpetually trying to sell me any Mazda 6 they had in stock. My constant reply was "Email me when you have a diesel sedan for sale."

I finally gave up last year and Chevy sold me my Cruze sedan. 

To be fair to Mazda, they spent years of engineering development trying to make their diesel engine work without urea injection for NOx reduction. Apparently those years were spent doing this because the engineers pointed to how VW achieved it with their TDI engines... and then Dieselgate broke into the news. I can imagine there was a lot of quiet reflection and apologies from those Mazda engineers after the years they realized they had been duped by VW. That has to hurt.


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## grs1961 (Oct 23, 2012)

Barry Allen said:


> As a totally unrelated side note: I'm sick and damned tired of waiting for that Mazda diesel engine, along with other auto makers who teased the idea and then never delivered.


You can get Mazda diesels here in Australia, along with several other Asian and European versions.

It's probably more to do with perceived saleability in the USA than anything else, many car company executives (and engineers) have a lot tied up in getting "their" pet engine into the next chassis, so they lie, a lot.

Shortly after I bought my Cruze I was told be a GM-H executive that "Australians don't buy diesels."

I called him a sack of etcetera that shouldn't be allowed to deal with wooden cars, much less real ones, as he seemed to find it necessary to lie about it.

He really was stupid enough to insist that there was no such beast as a diesel Cruze in Oz, which didn't work out well for him, the people he was trying to impress were quite aware that it existed.


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## Barry Allen (Apr 18, 2018)

grs1961 said:


> You can get Mazda diesels here in Australia, along with several other Asian and European versions.


American emission regulations have strangled the diesel car industry here.


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## Barry Allen (Apr 18, 2018)

FOLLOW-UP
I emailed the liquid fuels sales manager of my favorite supplier to ask about the gelling issue. Here is his reply:

_*We have an anti -gel deicer in the fuel which our laboratory test has rated it at -12 degrees opperability, when the forecast called for -18 we also added #1 Diesel to take to approximately -18 . I would like to see the inside of the filter that plugged if you still have it.*_

The problem appears to be that I filled up my car and immediately drove north to park it overnight where the temperature was down to -22°F. The fuel was probably right on the edge of the CFPP and I was really close to pushing it too far. 

My cousin further north experienced -27°F overnight to the point that he woke up with his house at 55°F and the furnace had been running non-stop all night. He had to build a raging fire in his fireplace to warm the house back up. Had I parked the car somewhere about 2-4°F colder I wager it wouldn't have started.


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