How To extend glow time with Vag-com - ALH

gralaska

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Oct 23, 2010
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Fairbanks
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2000 Jetta
Extend glow time without Vag-com

I guess my first question is what is "Vag-com"? My second is, is there a way to extend glow time without Vag-com?
 

MonsterTDI09

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Use the search option. It is your friend.

Search is your friend in not a answer.We are here to try help out people.If you don't know answer that is okThen try to help him out to find answer.


Ross tech should have your answer.I don't know answer off hand but I do know were he can get.
 

egibbys

Veteran Member
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Feb 20, 2008
Location
Salt Lake City, UT
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1999 Jetta TDI GLS
Search is your friend *is* not *an* answer.
Actually it is. Searching will answer both questions of his.

But to be nice:

Vag-com, now called VCDS, is a way to communicate with your car's computer via a Laptop and cable. http://www.ross-tech.com/

No you can not extend glow time without VCDS for actual driving purposes. It can be extended by unplugging the coolant temperature sensor but this is not recommended since your car will always think its super cold outside. This will effect timing, etc. Doing this is for testing your glow plug relay.

My recommendation is if you are going to keep the car for a long time then the purchase of a VCDS cable is a great investment. Plus they are easily resold.
 

Lug_Nut

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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
I guess my first question is what is "Vag-com"? My second is, is there a way to extend glow time without Vag-com?
The second way is to turn the key to the OFF position (after the dash glow indicator has turned off), and then right back to the ON for a second (or third) pre-start, minimum wait episode.
A more effective way may be to listen if the glow plug relay can be heard as it switches on and off. If you can hear it (1996~1998.5 A3 and B4 are inside and can be heard), then leave the key in the ON position after the glow plug indicator lamp has gone out. Turn the key to START after you hear the glow plug relay click off.
If you have a newer TDI with the relay under the hood and inaudible, then simply wait after the glow indicator has gone out. The glow plug relay remains on about twice again as long as the separate yellow dash indicator was lit. If 5 seconds of illuminated indicator, wait another 10 seconds, then crank.
 

Shizzell

Veteran Member
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US
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2000 Golf 1.9L GL 2dr
Are people really just that lazy to turn the key a few extra times?
Is it a crime to invest in one's management of wrist movement?!

Also other people that are driving the car may not think to do it 2-3 times.
 

NarfBLAST

Top Post Dawg
Joined
Mar 3, 2002
Location
Waterdown, Ontario, Canada
TDI
2001 Golf 5MT
This mod is not for when it is super cold and you want to double the glow time. I don't think this mod changes the "maximum glow time".

This mod is best for when it is just around freezing and the glow time is extremely short, or non existant. That is when this mod is great because it gives you a 3 seconds instead of 1 second of glow and really helps!
 
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Shizzell

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2000 Golf 1.9L GL 2dr
I'd rather pause before starting, than turn the key like a madman looking like a fool. Gracefulness is worth something, maybe not in your eyes, but to some people. I also dont need to do all of the other things that accompany turning the key on when I just did it a few times.
I know people that understand you let the glow plugs ignite before starting a diesel, but they may not think to do it a couple times.
 

Wingnut

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Silver 2003 Jetta Wagon
I'd agree that the glow plugs need the most help beyond what the VW engineers programmed in the ECU right around 32-45* F (just above freezing). This is when I triple glow, and I get the same result. I've never had a non-existent glow at these temperatures, though.
Glow time can be non existent on some cars at low temperatures (not all are created equally), so you can quintiple glow, but if the ecu isn't calling for any glow, you just wasted 5 key cycles as it didn't do anything. By doing this adjustment, it does 2 things. Increases the glow time (for the lazy people as you call them) but also increases the temp at which they start to glow. So, if your car does not glow at 45* F, cycling the key 5 times will do nothing. By making this adjustment, it does activate the plugs at that 'sweet spot' that many cars have a hard time starting with no glow.

This mod can also be used in reverse for people in high altitude locations where the plugs will activate for extended times based on barometric pressure, not just temperature. They may not need any glow time at 5000 feet above sea level on a 70* day, but VW engineers decided that they do. By adjusting the adaptation value the opposite way, you can decrease the glow time or elimiate it completey if you want.

The bottomline is that everyone is different and can do to their cars what they want. If you don't want to do this adaptation, that is certainly your right. You do not need to insult those who do want to make adjustments to their cars.
 

Shizzell

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Location
US
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2000 Golf 1.9L GL 2dr
But I guess bottom line, no one really needs glow plugs. They're there mainly for improving emissions.
False.

You do not need to insult those who do want to make adjustments to their cars.
Agreed.

Yep, you got me right. I prefer function over form, like men usually do.
Wow. You know what beats this? Better function, and better form; which glow plug extending does. There is no reason not to keep your starts to one key turn. I'm surprised you are fighting this so adamantly, and then even adding snide comments. Wow.
 

Wingnut

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Location
Toronto & Whitby
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Silver 2003 Jetta Wagon
I was just looking for one good reason for this mod, and so far, I've gotten several "kinda-sorta-maybe-not really" reasons. (Ex. High altitudes: turn the key to "start" before the glow plug light turns off. Same result.) But I guess bottom line, no one really needs glow plugs. They're there mainly for improving emissions. I've seen lots of off-highway diesel engines that don't have glow plugs, and they have to be cranked for at least 10 seconds before they finally run on their own power. During the first minute they run, they sputter and smoke badly, and that's considered to be normal.
I gave you one good reason...SOME cars do not glow at all at a certain temperature threshold. So no amount of multiple cycling of the key will do ANYTHING. So your argument of telling people not to be lazy and just cycle the key a few times has no validity. And if you are OK with long cranking & smoke shows due to no glow time, good for you. That is your right. But some people have respect for their neighbors and don't want to create a smoke show, or extend the cranking time when its cold and wearing out their starter or battery prematurely. This mod can possibly help those situations. It may not help everyone, but can help some. Is that wrong?

What is your point in this thread anyway? If you don't want to do this mod, that is perfectly fine. No one has said that you HAVE to do it. But please respect everyones decision to do what they want to their own vehicles. There is no need to insult anyone just because you don't like it.
 

VeeDubTDI

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Well said, Wingnut.

It's time to administer some chill pills to this thread. :rolleyes:
 

megaladon6

Veteran Member
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Nov 1, 2004
Location
Danbury CT
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2003 Jetta GLS
glow plugs are for emissions...
really?:rolleyes:

many of those engine without plugs most likely have an intake heater instead--mercedes/freightliner do this.

hell, don't believe us? disable your glow plugs and try and start the car when it's been sitting in 15*F weather. better yet, try it with a ford powerstroke.
 

VeeDubTDI

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If glow plugs were only for emissions, then my 1.6 should have fired right up with dead glow plugs. But no... it didn't... http://www.youtube.com/watch?v=oFPjQWGdpvw

Some engines can start with no pre-heat... others require pre-heat at all temperatures... others require pre-heat below a certain point. It all depends on the engine design.
 

rotarykid

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1997 Passat TDI White,99.5 Blue Jetta TDI
If glow plugs were only for emissions, then my 1.6 should have fired right up with dead glow plugs. But no... it didn't... http://www.youtube.com/watch?v=oFPjQWGdpvw

Some engines can start with no pre-heat... others require pre-heat at all temperatures... others require pre-heat below a certain point. It all depends on the engine design.

VW/Audi IDI's do require glow plugs at every cold start, it is a lot harder to get an IDI cranked when cold. Many of these engines will not crank without at one glow plug cycle when cold even in warmer ambient temps......

But most DI diesels can get going without glow plugs except in the coldest temps with a few extra rpms cranking. And the answer is yes, engine and water system glow plugs on DI diesel engines like our TDIs have a lot to do with passing emissions. But once the temps go below 40 * F glow plugs make a real difference in cold starts. However I have seen rotary type injection pump TDIs get going as low as ~20 * F without glow plugs running a cycle but it created a local little brown cloud.
 

FlyGuy2480

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1998 VW Jetta TDI (A3 platform, AHU engine)
VW/Audi IDI's do require glow plugs at every cold start, it is a lot harder to get an IDI cranked when cold. Many of these engines will not crank without at one glow plug cycle when cold even in warmer ambient temps......

But most DI diesels can get going without glow plugs except in the coldest temps with a few extra rpms cranking. And the answer is yes, engine and water system glow plugs on DI diesel engines like our TDIs have a lot to do with passing emissions. But once the temps go below 40 * F glow plugs make a real difference in cold starts. However I have seen rotary type injection pump TDIs get going as low as ~20 * F without glow plugs running a cycle but it created a local little brown cloud.
Thank you, that answers my question.
 

mystic.bertie

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VW GOLF (AJM) 1.9TDI 115BHP
would i be right in thinking that you have to wait till your engine cools to say 10 deg and extend the glow time at that whilst at that current temperature, then it will be on for longer at 10 degrees and below?:D
 

rdkern

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Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
It's my understanding that changing the gp time will extend it at all temps, and give it a little higher temp at which it starts. I've been wrong before....
 

mystic.bertie

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VW GOLF (AJM) 1.9TDI 115BHP
It's my understanding that changing the gp time will extend it at all temps, and give it a little higher temp at which it starts. I've been wrong before....
ah so the temp and times cant be adjusted seperately??

i followed the guide on page 1, i changed the number to 32700, the temp was showing 28 degC, i tested it, saved it, switched ignition off then on, opened up the controller, logged in, adaptation 12, the time was still showing 0. However this morning the glowplugs came on for a few seconds so it must have worked.

do i just need to play with the figures if i need another second longer or is there some kind of logic to the numbers? :D
 

megaladon6

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2003 Jetta GLS
28C? IIRC thats way too warm for the glow plugs to activate. You have to be below around 40F which is 10C i think?
 

mystic.bertie

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VW GOLF (AJM) 1.9TDI 115BHP
28C? IIRC thats way too warm for the glow plugs to activate. You have to be below around 40F which is 10C i think?
that was the current engine temp when i did the adjustment. Do i need to wait till the temp is less ie 10C or whatever i want and then do the adjustment?:)
 

megaladon6

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2003 Jetta GLS
As long as the engine temp is below 10c, ylu can adjust. It will affect the entire scale, so all temp/times will be affected. If you bave an issue below a specific temp, your best bet is to adjust ther so you know if it goes away.
 

Wingnut

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Silver 2003 Jetta Wagon
ah so the temp and times cant be adjusted seperately??
i followed the guide on page 1, i changed the number to 32700, the temp was showing 28 degC, i tested it, saved it, switched ignition off then on, opened up the controller, logged in, adaptation 12, the time was still showing 0. However this morning the glowplugs came on for a few seconds so it must have worked.
do i just need to play with the figures if i need another second longer or is there some kind of logic to the numbers? :D
No, the 2 variables cannot be changed seperately. The adjustment does 2 things. It increases the temperature at which the glow plugs activate, and increase the duration of the glow. But the 2 variables are linear and not adjustable seperately.

You can make the adjustment at any time, but you would not be able to see the reults with a warm engine. You can only compare the before and after values if the coolant temp is below the threshold at which the plugs become active.

The best way to adjust it is to do the adaptation with a cold engine. Then, you will know exactly how much glow time you will get at any given adaptation value at the current cold temp. In your case, you could just lower the adaptation value by another 20 points or so and that should give you another second or two of glow assuming the temp is the same the next day.

As far as a concrete formula of what adaptation value equates to what temp vs duration, I have not measured any of that info other than the 2 temps in the original post. I suppose one could make a chart and plug in the 3 variables (temp, duration, adaptation value), but that would take a lot of work.
 
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mystic.bertie

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many many thanks for the info mate, i have taken another 20 off of the value and checked my settings with a cold engine, its reading just under 4 secs at 12C, so it starts much better now when cold, no spluttering into life and no smoke.

im running homemade biodiesel and i have no idea how good the glow plugs are so this has solved my problem without any cost yipee. cheers dudes
 

megaladon6

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2003 Jetta GLS
IIRC, you really cant go too far with the adaptation. Since the plugs glow for a few minutes after startup, in cold conditions, you dnt have to worry about a few seconds.
 

gordonowusu

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Audi B6 2.5 TDI
Hi all,

I have a 2004 Audi A4 V6 tdi. the car didnt have a quick start the first day i took delivery of it. it turns over and over for about 3seconds before it fires up. the problem got worse over the weeks and was told to replace glow plugs by my mechanic. I did as such and replaced all 6 plug with new ones ordered from Audi. the problem was still there and it became worse as the days go by. when it finally fires up, it puffs of white smoke from the exaust for a while before it clears up. I have researched on this forum and I found the glow plug relay was not clicking so I replaced the coolant temperature sensor with a new. I also replaced the glow plug relay 202 with a new one as well but still no improvement.
the car fires up almost instantly when I unplug the coolant temperature sensor as i hear the relay click and the glow plug starts glowing. But will never start when the sensor is plugged unless I keep cranking and cranking.
I have also checked the in-tank fuel pump and it works ok. what I noticed is when I turn the ignition on, the pump wont pump fuel unless I crank before it does. is this normal with this type of engine (BDH)?
I have also changed the fuel pump relay 395 but still no improvement.

I live in tropical Africa where our temperatures is around 22 degree celcius in the morning and I know VW engines will not need glow plugs at this temperature to start. but I think with a milage of 250,000km I will need a bit of glow time to start this engine.

I connected to VAG. com just to extend the glow time to see if it works. so I canged the default value from 32768 which give 0 seconds glow time at a temperature of 24 degrees to 32700 as described in this forum http://forums.tdiclub.com/showthread.php?t=123304
Intrestingly, the glow time still remained at 0 seconds no matter the value I put in. does this mean its not communicating with the ECU?

I read on other forums that the timing might be off which is giving difficult start but I also think its not timing since the car starts fine if the CTS is unplugged.

I dont know what to do now and really need your help as you guys are the experts and I follow almost all the problems menber post in here and the solutions you give them.
what else should I do since I have changed the following but the problem is still there.
1. coolant temperature sensor
2. glow plugs
3. glow plug relay 202
4. fuel pump relay 395,
5, fuel filter
6. air filter
7. coolant
are there order relays i need to check as well?
there are no code when connected to VAG.com except the the coolant temeperture sensor which is because I disconnected it to start the car.

sorry for being lenghty in my mail but I please need your help.

thanks,
Gordon.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
The adaption to the glow plugs increases time at a temperature. If you're at 40C, you can't adapt it enough to glow the plugs - even with 250KKm, it shouldn't need them.

The timing is likely the issue, and "masked" by the long glow plug times. Try to advance it a bit. You have VCDS, so use it. At least test the static timing.
 

FlyGuy2480

Veteran Member
Joined
Nov 25, 2009
Location
Western Washington State
TDI
1998 VW Jetta TDI (A3 platform, AHU engine)
Hi all,

I have a 2004 Audi A4 V6 tdi. the car didnt have a quick start the first day i took delivery of it. it turns over and over for about 3seconds before it fires up. the problem got worse over the weeks and was told to replace glow plugs by my mechanic. I did as such and replaced all 6 plug with new ones ordered from Audi. the problem was still there and it became worse as the days go by. when it finally fires up, it puffs of white smoke from the exaust for a while before it clears up. I have researched on this forum and I found the glow plug relay was not clicking so I replaced the coolant temperature sensor with a new. I also replaced the glow plug relay 202 with a new one as well but still no improvement.
the car fires up almost instantly when I unplug the coolant temperature sensor as i hear the relay click and the glow plug starts glowing. But will never start when the sensor is plugged unless I keep cranking and cranking.
I have also checked the in-tank fuel pump and it works ok. what I noticed is when I turn the ignition on, the pump wont pump fuel unless I crank before it does. is this normal with this type of engine (BDH)?
I have also changed the fuel pump relay 395 but still no improvement.

I live in tropical Africa where our temperatures is around 22 degree celcius in the morning and I know VW engines will not need glow plugs at this temperature to start. but I think with a milage of 250,000km I will need a bit of glow time to start this engine.

I connected to VAG. com just to extend the glow time to see if it works. so I canged the default value from 32768 which give 0 seconds glow time at a temperature of 24 degrees to 32700 as described in this forum http://forums.tdiclub.com/showthread.php?t=123304
Intrestingly, the glow time still remained at 0 seconds no matter the value I put in. does this mean its not communicating with the ECU?

I read on other forums that the timing might be off which is giving difficult start but I also think its not timing since the car starts fine if the CTS is unplugged.

I dont know what to do now and really need your help as you guys are the experts and I follow almost all the problems menber post in here and the solutions you give them.
what else should I do since I have changed the following but the problem is still there.
1. coolant temperature sensor
2. glow plugs
3. glow plug relay 202
4. fuel pump relay 395,
5, fuel filter
6. air filter
7. coolant
are there order relays i need to check as well?
there are no code when connected to VAG.com except the the coolant temeperture sensor which is because I disconnected it to start the car.

sorry for being lenghty in my mail but I please need your help.

thanks,
Gordon.
At 22 degrees Celsius, the engine should not need glow plugs to start, so the computer does not turn on the glow plugs. When you unplug the coolant temperature sensor, the computer does not know the temperature of the engine, so it assumes a much colder value (probably 0 degrees Celsius) and therefore turns on the glow plugs prior to starting.

The glow plug operation is simply hiding another problem with your engine. Two likely candidates are low cylinder compression and offset injection timing.

Since you have VAG-COM, you should check the injection timing first. Instructions for that is here: http://ross-tech.com/vag-scope/TDIGraph.html If the timing looks good, then you should do a compression test.

Regarding the in-tank fuel pump: That behavior sounds normal to me. The main purpose of that pump is to prime the fuel in case any vapors have entered the fuel lines. If I'm not mistaken, the car will run fine without that pump at all. (You can verify that by disconnecting it.) As an example, 1Z, AHU, and ALH engines don't have an in-tank fuel pump.

Regarding the glow time adaptation value: That behavior also sounds normal to me. The ambient temperature is too hot for the computer to register any glow time, regardless of the adaptation value.
 
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