BEW, Glow Plug settings.....

towforce

Veteran Member
Joined
Mar 12, 2005
Location
West Coast, Canada
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Jetta Wagon, 2005, Red
A few questions about the glow plug system on my 05 BEW.

Short background, 460,000kms, I had the VW Ceramic to Steel recall done (way back....), Recently had a Stage One Malone Tune to deal with "Warm start" issues that the Tune solved (Tune ID ends with "SG"), No Codes recorded, Temp sensor seems to be reading correctly, Anything less than 3-4 C and she gets grumpy to start. New battery, good crank speeds, runs perfect warm.

So... I've gone from a Warm Start issue to a Cold start issue.

My Questions,

-With the VCDS I see a pre-glow setting of 1.6 seconds, is this normal?
-Is it possible the GP's are failing and not heating? (and not throwing a code?) We don't get allot of cold weather and these plugs have been in for at least 12 years.... my old 82 Rabbit used to carve through GP's like crazy but I honestly don't know much about the ones in the BEW.

-What is the best way to Log a cold start? If I'm key off, I don't have a connection to the controller, so how do I catch the initial glow plug event?
Below is what I did log (edited up to crank and start ).....

Thanks

**********************************************
Sunday 11 November 2018 09:56:26:63327-VCID:27432875951A4B72B7-515A VCDS Version: Release 18.9.0 (x64) Data version: 20180927 DS296.0
038 997 016 L ADVMB R4 1.9L EDC G000SG 3791
G012 F0 G012 F1 G012 F2
Marker TIME Group 12 - Field 0 TIME Group 12 - Field 1 TIME Group 12 - Field 2
STAMP Glow Status STAMP Pre-Glow Period STAMP Supply Voltage - (Terminal 30)
s V
10.12 0 10.12 1.61 10.12 14.67
10.28 0 10.28 1.61 10.28 14.29
10.44 0 10.44 1.61 10.44 14.21
10.59 0 10.59 1.61 10.59 14.14
10.75 0 10.75 1.61 10.75 14.14
10.91 0 10.91 1.61 10.91 14.14
11.08 0 11.08 1.61 11.08 14.14
11.23 0 11.23 1.61 11.23 14.14
11.39 0 11.39 1.61 11.39 14.14
11.54 0 11.54 1.61 11.54 14.14
11.71 0 11.71 1.61 11.71 14.14
11.87 0 11.87 1.61 11.87 14.14
12.03 0 12.03 1.61 12.03 14.14
12.19 0 12.19 1.61 12.19 14.14
12.34 0 12.34 1.61 12.34 14.14
12.5 0 12.5 1.61 12.5 14.14
12.67 0 12.67 1.61 12.67 14.21
12.83 0 12.83 1.61 12.83 14.21
18.3 0 18.3 1.61 18.3 14.21
19.47 1010000 19.47 0 19.47 13.98
19.62 1010000 19.62 0 19.62 13.98
19.78 1010000 19.78 0 19.78 13.98
19.94 1010000 19.94 0 19.94 13.98
20.09 1010000 20.09 0 20.09 13.98
20.25 1010000 20.25 0 20.25 13.98
20.4 1010000 20.4 0 20.4 13.98
20.56 1010000 20.56 0 20.56 13.98
20.72 1010000 20.72 0 20.72 13.98
20.89 1010000 20.89 0 20.89 13.98
21.04 1010000 21.04 0 21.04 13.98
21.21 1010000 21.21 0 21.21 13.98
21.37 1010000 21.37 0 21.37 13.98
21.54 1010000 21.54 0 21.54 13.98
21.71 1010000 21.71 0 21.71 13.91
21.87 1010000 21.87 0 21.87 13.91
22.03 1010000 22.03 0 22.03 13.91
22.19 1010000 22.19 0 22.19 13.91
22.34 1010000 22.34 0 22.34 13.91
22.5 1010000 22.5 0 22.5 13.91
22.65 1010000 22.65 0 22.65 13.91
22.81 1010000 22.81 0 22.81 13.91
22.97 1010000 22.97 0 22.97 13.91
23.12 1010000 23.12 0 23.12 13.91
23.28 1010000 23.28 0 23.28 13.91
23.44 1010000 23.44 0 23.44 13.91
23.59 1010000 23.59 0 23.59 13.91
23.75 1010000 23.75 0 23.75 13.91
23.9 1010000 23.9 0 23.9 13.91
24.06 1010000 24.06 0 24.06 13.91
24.22 1010000 24.22 0 24.22 13.91
24.37 1010000 24.37 0 24.37 13.91
24.53 1010000 24.53 0 24.53 13.91
24.71 1010000 24.71 0 24.71 13.91
24.87 1010000 24.87 0 24.87 13.91
25.03 1010000 25.03 0 25.03 13.91
25.19 1010000 25.19 0 25.19 13.91
25.34 1010000 25.34 0 25.34 13.68
25.52 11000000 25.52 0 25.52 11.32
25.69 11000000 25.69 0 25.69 11.86
25.84 11000000 25.84 0 25.84 12.08
26 11111111 26 0 26 12.31
26.15 11111111 26.15 0 26.15 12.92
26.31 11111111 26.31 0 26.31 13.07
26.47 11111111 26.47 0 26.47 13.07
26.62 11111111 26.62 0 26.62 13.07
26.78 11111111 26.78 0 26.78 13.07
26.94 11111111 26.94 0 26.94 13.07
27.09 11111111 27.09 0 27.09 13.22
27.25 11111111 27.25 0 27.25 13.45
27.4 11111111 27.4 0 27.4 13.91
27.56 11111111 27.56 0 27.56 14.59
 

JDSwan87

Black Swamp Thing
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2001 Jetta TDI, 5 speed Lagoon Blue Metallic(sold); 2005 Jetta TDI Wagon auto
Can't help you with your VCDS log but you need to find out how many volts your harness is putting out, 5V or 7V. Easiest way would be to ask your tuner what GP software they installed...
 

towforce

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Jetta Wagon, 2005, Red
Sent them a note to check on the output. When VW did the recall they installed the N-105-916-07 Glow plugs, which I'm pretty sure are 5V. (have had a brand new set sitting on the self for almost 10 years.....)
 

JDSwan87

Black Swamp Thing
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Location
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TDI
2001 Jetta TDI, 5 speed Lagoon Blue Metallic(sold); 2005 Jetta TDI Wagon auto
Sent them a note to check on the output. When VW did the recall they installed the N-105-916-07 Glow plugs, which I'm pretty sure are 5V. (have had a brand new set sitting on the self for almost 10 years.....)
There was a 2nd TSB to revert back from 5V to 7V I believe... it could be possible your GP's need replacement, they still turn on up to 45*F I believe. What is your static timing like?
 

k_pt

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pt
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With that mileage, I would be looking for compression values.

Also 12 years for glow plugs is a lot, specially if they work a lot due to weather conditions.
 

towforce

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Did not specifically look at the Torsion Value, but warm it had been set at "0", did note during the last logged start, -3 C, The value started off around 9, and was dropping to 6 within the first minute.

The second recall was not extended to my vehicle and they remained 5v .

Will plug in and double check the Torsion Value when the "Warm" vehicle arrives back home tonight.

Martin
 

JDSwan87

Black Swamp Thing
Joined
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Location
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2001 Jetta TDI, 5 speed Lagoon Blue Metallic(sold); 2005 Jetta TDI Wagon auto
Did not specifically look at the Torsion Value, but warm it had been set at "0", did note during the last logged start, -3 C, The value started off around 9, and was dropping to 6 within the first minute.
The second recall was not extended to my vehicle and they remained 5v .
Will plug in and double check the Torsion Value when the "Warm" vehicle arrives back home tonight.
Martin
Torsion value and static timing are 2 separate things...
 

towforce

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Torsion value and static timing are 2 separate things...
So.... Enlighten me?

My BEW understanding is the belt/timing is set by the locked install possition of the cam belt and tweaked by the adjustment of the cam sensor via the cam sprocket, computer displays this setting in term of torsion value.... maybe I got it wrong or are you thinking I'm running the older VE.

"Static" timing is what you get on a BEW when you put the belt on.... Properly....I think. :rolleyes:

Martin
 

towforce

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Just a correction to a posting above re: Torsion value during the warm up from -3C..... My mistake, not Torsion value (I thought it was part of the group), I believe it is something like injection duration and is represented in Kw.

My bad.

Martin
 

k_pt

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pt
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Start of injection probably, usually starts at 10/9btdc
 

towforce

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I had some correspondence with my "Tuner" (Malone), they indicated that what ever the original GP voltage was (1st VW recall to 5v), it would have remained the same. Must admit, not a particularly satisfying reply as I could not get a confirmation that MY Tune was for certain the 5V version but it was an Email exchange and it would have probably been better to just walk in and ask.

Anybody know if you can use the VCDS to actually see the voltage output settings and times for the GP's?

For now, even tho I'm not seeing any codes, I'm going to do a little more work to properly assess what the GP's are doing and if they are simply too old to be producing enough heat to give a proper cold start.

It could be purely coincidence that I'm having a cold start issue since having the Tune performed.

Martin
 

JB05

Top Post Dawg
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I never had any GP recalls performed on my Golf. In the past I measured 5v @ idle and up to 7v @ 1500 rpm at the GP harness. I've been using the 5v steelies for a very long time with no problems.
 

wonneber

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2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I had some correspondence with my "Tuner" (Malone), they indicated that what ever the original GP voltage was (1st VW recall to 5v), it would have remained the same.
I would think the voltage is controlled in the G-P relay, not the ECU.
 

scurvy

Good Ol' Boy
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Location
Chicago IL USA
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2006 Golf
I would think the voltage is controlled in the G-P relay, not the ECU.

Relays are just electromechanical switches, they have no ability to regulate voltage.


In PDs, the voltage output to the glowplugs is indeed changed by the ECU via pulse width modulation. They originally came with ceramic glowplugs, rated at 7V. The seven volts were achieved by pulsing 12V at approximately 58% duty cycle. Unfortunately the original ceramic glowplugs were fragile little things and would crumble into extremely abrasive chunks if they were dropped or treated poorly.


So VW came up with a fix, steel GPs rated at 5V. These were accompanied by a recall tune from VW that lowered the voltage duty cycle (down to about 42%). None of the electrical components were changed aside from the plugs.


My experience is that the steel 5V plugs don't start for **** in actual cold weather. I will be getting retuned by RC to go back to 7V plugs.
 

towforce

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Somethings remain a mystery..... ;)

I've kept up glow plug saga and I well aware of the 7v-5v-7v evolution and ceramic-steel-ceramic material changes. Thanks to my Tuner I got a link to the VW bulletin that spells out the last change (a change that as the original owner I never received... tho, I'm pretty sure I heard about it and ignored it as I was a bit leery of the "New" ceramics...)

http://pics.tdiclub.com/data/500/PD_GlowPlugTechBul_12-2010.pdf

My cold start issue is a bit of a mix of issues, I had recently done a "tune" and just had a short stint in a somewhat cold starting condition (-3C). To be clear, up until this recent event, I never had an issue with cold starts and the 5v but out here on the West Coast of Canada, your seldom going to be taking the -20C North Dakota "death start".

Like I said earlier, I'm going to dig a little deeper into what's going on with the 5v GP's and determine if they are heating properly (after all, a 10 year old GP may be getting weak and contributing to the issue). I'm not saying I don't believe in the last version 7v ceramics I'm just not convinced my version of 5v's can't do better (as I believe they seem to work fine up until recently).

Should the opportunity come up, I may move to the latest 7v's but noted the following from the recall in the link above... to go back to a 7v configuration VW lists along with latest version GP's ( N 105 916 09 ) a Glow Plug Control Module is required (038 907 281 D ).

In the posting above, there is mention of the duty cycle and that a relay is just a relay... sound logical. My tuner indicates that the tune has nothing to do with the GP side things. So, just for clarity, is this how the GP System works?.....

-ECM (Engine Control Module) sends a request during the start to the GP System. (this is where the tuner does their magic... I assume)

-The GP system has a GP "Control Module" (this seems specific to the last upgrade and or the original "stock" version and is pre-programmed to either the 7v or 5v output?) my question here would be, is this module programmable?

-The GP "Control Module" controls a GP relay? Which switches the power on and off to the GP harness and GP's. (I would assume this "relay" should work with both the 7v and 5v versions.

Or... do I have this wrong, is the GP "control Module" and the GP "Relay" the same beast?

Of course there could be a million other things contributing to the cold start question, like compression, fuel (insert endless list of ideas here)... but given how well this high km engine is running (when its up and warm) I thought I would focus on the GP's for now.

Curious,

Martin
 

JB05

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I always thought the smart relay for the GP's, located under the cowl cover is what controlled the voltage. Years ago someone here was experimenting with capacitors attached somehow to this relay to up the voltage to 12 so to be able to use 12v steelies. I tried this and it did work, but with a constant CEL. I don't mess with this anymore.
 

towforce

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Jetta Wagon, 2005, Red
A little further digging and this is what I found....

I started with the Bentley diagnostic procedures for output on the GP Harness, disconnected the coolant sensor, pulled the GP harness off of the GP's and hooked up the voltmeter between a good ground and one of the outputs on the GP harness. (To my understanding this will set up the cold start default?). According to the instructions I should see voltage present for 20 seconds. What the test yields:

-roughly two seconds of 7-8 volts, followed by about 12 seconds of 2-3 volts (post glow?)

-I also tested the resistance of the GP's in the head and brand new ones out of the box and they all measure roughly 3-5 ohms.

I have no idea what sort pre-glow, post glow times I should see with the temp sensor pulled but the total duration is less than 20 seconds mentioned in the Bentley procedure (about 15 seconds).

Coming back to my initial post, for clarification, I had the first recall done and not the second so I'm running the the 5v steels (confirmed) and they had worked well enough up until my recent Stage One Malone tune. (Again to be fair to Malone, maybe just a coincidence but since the tune, my first cold starts have been poor). I'm also going to toss in that I carefully checked the initial VW work and confirmed that they installed a set of 5v GP's and did not install a new GP control module (so it is the original) and did the flash for the recall (and ran this way for over 8+ years).

So, a few things jump out for me, first, based on the test above, I'm seeing a initial voltage of 7-8 volts, looks wrong to me since I'm running 5 volt GP's and looks like an issue for my tuner? (or is it an issue at all?)

Second, I don't see the 20 seconds of voltage prescribed in the test (not sure if this is supposed to be pre-glow or post glow but net is only 15 seconds).

Third, I preformed the test with both coolant sensor unplugged and plugged and it resulted in the same results (Its plus 4 or 5 C for the test). This suggests a faulty coolant sensor but I'm a bit skeptical as both gauge and Vag-Com spec for coolant temps seem to be the same and accurate)

As is, I would really hate to be trying to pull any sort of serious cold starts. Anybody interested in commenting on the results of the test?

Thanks

Martin
 

Alchemist

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'04 ALH Golf
Here is some theory of operation that should clear up most of the mystery.

The "glow plug relay" is in fact an electronic module which doesn't have an electromagnetic coil or moving contacts. Instead it used transistors to switch power in response to commands from the ECU and thus control effective voltage to the glow plugs. It does this by pulsing the 12V directly from the battery on and off at short intervals. This is called pulse width modulation (PWM).

The ratio of on to off time makes 12V act like lower voltages, but since it is pulses, most meters can't read the effective voltage accurately as it is constantly changing. The ECU determines the necessary output from the control module and applies pulses to the control input at the on/off ratio that will provide the required power to the plugs.

The capacitor mentioned earlier was connected to the control line from the ECU. This had the effect of smoothing out the pulses and caused steady 12V out from the control module.

As noted, a 58% duty cycle will have an effective voltage of 6.96V and 42% will be equal to 5.04V based on a battery at 12V. The only way to measure this accurately is with an oscilloscope, but connecting a lamp such as a brake light bulb will give a pretty good indication of the output.

To get a better idea of the health of the CTS, check the coolant, fuel and intake air temperatures after the car has been off overnight. They should all be in close agreement.
 

towforce

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Alchemist, Thanks!... more or less what I believed to be the function of the "magic" taking place in what most call the "Glow Plug Relay" (up in the plenum beside the ECM).

Interesting way to assess the CTS, and yes multiple corresponding temps do seem to match but I will recheck in the morning. One interesting observation.....

At first, I thought disconnecting the CTS would default to a cold start (max glow plug time and settings). Thing is, it looks like if the data is missing, the ECM seems to retain "last data" or "other data" (probably air and fuel) as default (the disconnected CTS coolant data continued to display the last temp reading, and tossed the code). Could be wrong but that's the way it looks to me.

Where I'm at now (after getting a reading of 7-8volts initial glow, using a pretty good digital meter and seemed to produce a pretty stable consistent reading), it looks like my Tuner may have set the GP's for the latest 7v version and I may solve the cold start by just installing the new 7v Ceramics. (Sorry Owain!... kind of what it looks like it after testing the voltage output). In mild temps, my bet is the 5v's wouldn't suffer much by the high voltage but would also not heat as quickly so both pre and post glow would net a lower temp?

Which is why when I started this thread was to find out some details about the duty cycle and times allocated to various events (pre-glow and post glow times and voltages). With that I would have a pretty good idea as to what settings I have and why the GP's might not be working correctly since the Tune.

I'm really curious what the difference are in voltage and times for at least the 5v steels and the 7v ceramics (last version).


Do you know if you can use the Vag-Com to see the settings of the duty cycle?
 

Peroni

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2005 Mk4 Jetta TDI, 2014 Passat TDI SEL, 2015 Jetta TDI SEL
Any idea what would cause the plugs to not receive full voltage? With the coolant sensor unplugged I get a max of 2.47V at all four plugs. With the sensor plugged in I get nothing, even when it was 30°F this am. The 5V plugs ohm out okay. VCDS scan brings up no codes and there is no CEL. Car has been getting harder and harder to start even with temps in the low 40's.
 

towforce

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Joined
Mar 12, 2005
Location
West Coast, Canada
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Jetta Wagon, 2005, Red
Any idea what would cause the plugs to not receive full voltage? With the coolant sensor unplugged I get a max of 2.47V at all four plugs. With the sensor plugged in I get nothing, even when it was 30°F this am. The 5V plugs ohm out okay. VCDS scan brings up no codes and there is no CEL. Car has been getting harder and harder to start even with temps in the low 40's.
Have you had a look at group 12 (Engine 01- Measuring Blocks), to see what your Pre-glow is set at and if your CTS is reading correctly (right side of the group will display coolant temp)?

Group 12 will also display the status of the plugs (what they are doing, on/off/pre/post/after glow, hover your mouse over the status it will give you list)

The other thing is your peak voltage is quite brief, either 2.4 seconds or 1.6 seconds, Prop up your meter so you can see it as you cycle the key. If you cycle more than once, the pre glow time displayed in the group may drop to 1.6 or less seconds.

If you missed the initial pre-glow, It will then drop to its post glow status (which sounds right with your 2.47 reading)... btw... this will be followed with after glow (while the engine is running) Maybe your CTS may be pooched? What sort of start are you getting with the CTS unplugged?

Curious, are you running 5v steels or the latest version of 7v ceramics?

Martin

Martin
 

towforce

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Mar 12, 2005
Location
West Coast, Canada
TDI
Jetta Wagon, 2005, Red
Must say I'm a little surprised that there is so little technical information on how the PD glow plugs work. And I don't just mean, "they turn on and they get hot" kind of way.

Maybe I've just dug too deep but I find it interesting that there is a Pre, Post and afterglow. That there are variables in time and voltage to each event, with temperatures altering those variables.

Toss in the fact that BEW owners have had the confusing journey of 7v ceramic, 5v steel and finally New 7v ceramic.

What would be kind of cool is to see a chart that compares time, temp, versions.
 
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