How many times to you cycle your glow plugs in cold weather?

tikal

Veteran Member
Joined
Apr 18, 2001
Location
Southeast Texas
TDI
2004 Passat Wagon (chainless + 5 MT + GDE tune)
I just returned from a road trip from Texas through Arizona and New Mexico and I learned that my ageing Passat struggles a bit in cold weather (nights around 20 F or so). First when I cycled the glow plugs about six times or so the car really struggled to start. Lots of smoke (white) and after several attempts, when it did start, the car run very rough. So the next time in Albuquerque I cycle the glow plugs twenty (20) times and the car started beautifully and almost no smoke or shaking!

So is this normal for our ageing B5.5 or is my Passat a 'Southern' car and not used to the cold :( ?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Something is not right with your car. Even at single digit temps, my BHW starts after a single (albeit long) preglow period. It is a little stumbly and smokey, but it always starts. It was -7F this weekend... and it still started.

Which glow version does your car currently have? And is the software properly matched to the glow plug voltage? You may also have a loss of fuel prime causing a hard start. You can also verify the ECU is getting the proper temp sensor values via a scan tool.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
My GP light seems to have little correlation to the time the GPs are actually on. I leave the key in ON for 5 seconds after the light extinguishes.

My car will start with a single preglow down to 0F without issue, but like OilHammer, mine is a little stumbly for the first few seconds.

This is only when I forget to plug it in of course. :D
 

pdq import repair

Veteran Member
Joined
Nov 6, 2016
Location
idaho
TDI
09 Jetta
I agree something else must be wrong , on my CR I wait a patient 5 seconds or so for the light to go out and hit the starter. I fires immediately at temps as low as -20 so far. I tried to cycle the glowplugs twice a couple of cold mornings and found it had a slightly extended crank time. I have gone back to the single run of the plugs and it fires normally again.

My BEW before this one also had no problems at all with cold firing with a single glow.
 

imo000

Top Post Dawg
Joined
Dec 13, 2005
Location
Cambridge
TDI
2009 M-B ML320 Diesel & '05 Passat TDI Manual 5-Speed
Is your battery good? Diesels need to spin faster during start up that gas engines. If you can't get the rpms with the starter, the engine will not start.
 

highmileage

Veteran Member
Joined
Sep 17, 2013
Location
new jersey
TDI
2005 passat bhw tdi (presently), 2001 jetta alh tdi (previously), 1998 jetta ahu tdi (previously)
I have cycled glow plugs up to three times to try and provide additional warmth for an easier start. However, recently have been down to two or one cycle. I began to wonder if I were reaching a point of diminishing returns by stressing the battery too much and not really making it easier to start. Does this make sense or is it not an issue? Thanks.
 

otty

Veteran Member
Joined
Nov 7, 2010
Location
Revelstoke, BC
TDI
2003 Passat W8=>TDI swap, 4Motion Wagon, PD130(AVF) 6Speed Manual, 2006 Jetta MKIV PD(BEW) Wagon 5Speed Manual
It has been about -20c (-4f)here the last few mornings. I do tend to cycle the glow plugs up to three times before trying to start but I wonder if it makes any difference. Usually it takes a good 3-5 seconds of cranking to start and then runs very rough and smokey for a couple of minutes.

I am not sure if cycling the glow plug helps. Usually I just worry about cranking too long and harming the starter. If it doesn't fire after about 3-4 seconds I recycle the glow plugs and try again. Always starts so far!
 

thundershorts

Top Post Dawg
Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
bet your gp's aren't ngk's if you are hard starting at 20f
 

Tom in PT

Veteran Member
Joined
Jun 7, 2017
Location
Twilight Zone, WA State
TDI
2005 Passat sedan - SOLD; 2013 Passat DSG; both purchased new
There was a glow plug recall for the '05 passat TDI and if the OP's car did not get that done it might be a contributing factor to the cold start issue.

My '05 starts easily in temps down to the teens F, one glow. If your battery is low or bad and the engine cranks real slow then all bets are off.

I have a 2001 Yanmar 3JH3 3 cyl diesel engine in a boat that starts instantly every time without using any glow at all, no matter how cold. That engine has good compression. If the OP's engine is worn out and lower compression than factory spec that might be an issue too. I have another marine diesel based on 1930's technology with no glow plugs and it does start in cold weather (below freezing) but it takes some cranking and the use of a cold start button which injects more fuel into the cylinders. That engine has about 12,600 hours on it, internals never been touched in almost 50 years of use.
 

Uberhare

Veteran Member
Joined
Sep 3, 2006
Location
Ontario, Canada
TDI
Too many.
Last year I thought I was ready for a -35 trip to Thunder Bay. Newish battery, new glows, coolant heater. Plugged in for 3 hours at the hotel (yes they have outlets available for use up there!), and the battery was still almost frozen. I got about 1 revolution before it died. Now I know why they use battery warmers in Sweden! Started instantly with a boost.

3 years ago, I had no issue at -25 for 2 weeks straight. Not driving the TDI this winter.
 

tikal

Veteran Member
Joined
Apr 18, 2001
Location
Southeast Texas
TDI
2004 Passat Wagon (chainless + 5 MT + GDE tune)
Something is not right with your car. Even at single digit temps, my BHW starts after a single (albeit long) preglow period. It is a little stumbly and smokey, but it always starts. It was -7F this weekend... and it still started.

Which glow version does your car currently have? And is the software properly matched to the glow plug voltage? You may also have a loss of fuel prime causing a hard start. You can also verify the ECU is getting the proper temp sensor values via a scan tool.
Thanks to all the folks who have contributed to this thread and my situation! I went to my notes of what was done to the car during the five speed MT swap in June 2013. Robby (used to live in Austin) installed the NGK hybrid ceramic glow plugs (part # N 105 916 09) and I specifically asked Mike at TD Tuning to, among other software upgrades, to tune the ECU for the new ceramic glow plugs. Mike said that he has no problem doing so.

Also this past June I had a new fuel filter installed so I am no sure if a loss of fuel prime would be an issue but I cannot discard it either. Still the fact that I had to cycle the glow plugs so many times (20) vs. what other folks experience are in frigid temperatures tells me that something is not right in the 'glow plug system' and I need to find a new TDI guru to check it out before my next trip to the mountains or somewhere colder than SE Texas (although these days we are experiencing plenty of cold for our area!).
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
And we have had several of the middle revision BHW cars that simply refused to start in the cold, sometimes not even *that* cold, like 25 F. VAG missed the ball on that one. Rocketchip had no issue making them start with the 5V Bosch plugs though. Mine has that combo right now.

Pretty sad that a fellow in PA can make Volkswagen's diesels start better in the cold that Volkswagen can. :rolleyes:
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
And we have had several of the middle revision BHW cars that simply refused to start in the cold, sometimes not even *that* cold, like 25 F. VAG missed the ball on that one. Rocketchip had no issue making them start with the 5V Bosch plugs though. Mine has that combo right now.
Pretty sad that a fellow in PA can make Volkswagen's diesels start better in the cold that Volkswagen can. :rolleyes:
 

Smokerr

Veteran Member
Joined
Sep 3, 2005
Location
Alaska
TDI
Passat Wagon GL,2005,Silver
Ours would originally start at -20 fine.

I seldom started it cold though, at least used the oil pan heater.

Its slowly gotten less happy, 0 is about the limit now.

New battery made no difference.

I have lost count of how many times they replaced the glow plugs.

First time I had to force them, they got it when they pulled out the original ceramic GPs and one was almost burned in half.

Then each time it was in after that they did it again! Had no records of it being done.

I have a battery heater as well as the Circulation Heater (that is a wonder) and no issues.

No Vagcom (yet)
 

tikal

Veteran Member
Joined
Apr 18, 2001
Location
Southeast Texas
TDI
2004 Passat Wagon (chainless + 5 MT + GDE tune)
Correct with the explanation below QuickTD. I had to ship my ECU to TD Tuning to do the re-programming, including the processor flash. Robby installed the ceramic NGK glow plugs and he did a great job with installing the manual transmission. Everything works like OEM (gain about 15% in MPG average), no engine lights. If I find somebody in the Houston area with a VCDS I will look for the ECU part number to verify as you state below.

The battery is fairly new, two year old, group size H7, AGM with the required electrical specs for the B5.5 TDI. There are of course other variables such as an ageing starter, etc. But the fact that cycling the glow plugs so many times 'fixed' the cold starting tells me I need to look more in that area perhaps.

Thanks for all your contributions to this thread ?

Pretty easy to check if you have the
correct software for the NGK's. Scan the ECU with VCDS and look at the ECU part number. The last digit indicates the revision level which, in the case of the Passat, indicates glow plug type.
Part numbers ending in "T" are for the newest NGK ceramics. "N" ECU's use the 5V steel bosch plugs that don't work very well and "R" is tuned for the original bosch 7V ceramics.
To switch glow plug types it is necessary to change the processor flash as well as the data. This normally requires bench flashing the ECU. The processor flash can't be changed via OBD2, except at a dealer. They have secret tools...
 
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