How To extend glow time with Vag-com - ALH - Page 14

ratkc135 · January 22nd, 2019, 21:45

From my research: am I correct in that if I don’t have any codes my GPs and harness are working normally? It was 5 degrees a couple days ago and it took 5-7 seconds of cranking engine to start. So I’m gonna try this GP trick and see if that helps. Otherwise could be a starter and/or battery issue. I noticed this earlier this winter and assumed battery. O’Reillys tested battery and alternator and both checked ok. So I just want to confirm the car would tell me if any GPs failed and/or if the harness is bad (I have a spare harness and set of plugs).

If this trick doesn’t help perhaps it’s my starter...

I have a 2002 with 179K miles.

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ratkc135 · January 27th, 2019, 16:54

So is 9.95s the maximum it uses? My coolant was -15.3C and no matter what value I used it never changed from 9.95.

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ratkc135 · January 27th, 2019, 17:06

Per a previous post: anything above 32768 decreases glow time....I’m going with that and left it at 32768. I guess since it’s so cold I can’t confirm if changes in adaptation is actually doing anything?

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greenskeeper · February 1st, 2019, 16:02

Quote:

Originally Posted by ratkc135

From my research: am I correct in that if I don’t have any codes my GPs and harness are working normally? It was 5 degrees a couple days ago and it took 5-7 seconds of cranking engine to start. So I’m gonna try this GP trick and see if that helps. Otherwise could be a starter and/or battery issue. I noticed this earlier this winter and assumed battery. O’Reillys tested battery and alternator and both checked ok. So I just want to confirm the car would tell me if any GPs failed and/or if the harness is bad (I have a spare harness and set of plugs).

If this trick doesn’t help perhaps it’s my starter...

I have a 2002 with 179K miles.

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I had an A3 so not certain if the A4s operate the same, but the ECU in my A3 would monitor GPs 1-2 and 3-4 to look for a difference between the pairs to trip the glow plug code. So if both pairs are bad but read the same to the ECU it won't trip the code.

I'd suggest testing for continuity on each glow plug by removing the harness. I would then test for 12v at each plug on the harness with the key on.

Additionally you could remove each glow plug and put 12v direct to them as a test, each glow plug should get bright red the entire length of the plug within 10 seconds of being energized.

greenskeeper · February 1st, 2019, 16:03

Quote:

Originally Posted by ratkc135

Per a previous post: anything above 32768 decreases glow time....I’m going with that and left it at 32768. I guess since it’s so cold I can’t confirm if changes in adaptation is actually doing anything?

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lower adaptation number increases glow time

MAXRPM · February 3rd, 2019, 00:46

2005passatsteve · February 3rd, 2019, 06:17

My jetta has 440,000km. Cranks great normal but in -15 or lower it is slow (diesel needs 600rpm approx min). I put a new starter on for $220. Night and day!!! Even at -29C it cranked over so fast! It started in only a few revolutions.
Because i am PD and my highest adaptation for some reason is 30,000 (and it is less GP time than the original 00000 value), i added a manual push button in my dash. I soldered 4 wires (trailer wiring) to each wire under hood just before it goes to the plugs. I soldered that to a main thick wire and ran it to the button. I fed the power to the button from one of the strip fuses on the battery. I tested it with a volt meter, and its awesome. Only snag is that the system is programmed to be full to the plugs, then immediately drop to 5v, so my button with 12v is scary - jusy 2-3sec max maybe.

djrhetoric · February 4th, 2019, 09:10

Quote:

Originally Posted by 2005passatsteve

diesel needs 600rpm approx min)

Wrong. More like ~300 before fuel is injected. But that might even be an old wives tale at this point based on what year you have.

2005passatsteve · February 4th, 2019, 14:33

Great job! I was always told minimum rpm to start a diesel ignition process was 600rpm (from a diesel pump repair facility) back in the old 1980's years. Reviewing your reply, i dug up the specs of "150-250" to ignite with heat of compression of air and the injected fuel into that heated zone. Man, even 300 sounds really really slow. I will put tach tape on my balancer and see what i get one day. I know for a fact that i LOVE my new starter!

TornadoRed · February 4th, 2019, 14:46

I've read 300 rpm here at TDI Club, and I've read 275 rpm. Whichever it is, anything lower results in fuel not being injected. Obviously the faster it cranks the more likely the engine is to start.

jackbombay · February 4th, 2019, 16:57

Quote:

Originally Posted by TornadoRed

I've read 300 rpm here at TDI Club, and I've read 275 rpm. Whichever it is, anything lower results in fuel not being injected. Obviously the faster it cranks the more likely the engine is to start.

I though 250 cranking RPM was the cutoff for no fuel injection, but I may be confusing that number with my 2003 sprinter.

As far as extending glow period goes, I don't really see the point, I've started my Jetta at -30F at high elevation and I've never messed with the glow duration. If you feel you need to do this you have something else that needs to be fixed, not the glow duration.

$.02

2005passatsteve · February 5th, 2019, 05:54

Something else wrong: yes! My car (jetta+passat PD's) used to start awesome, even in timmins. Then i did the stupid glow plug recall because ceramics were breaking off inside. They changed the voltage to the new s.steel ones. Then nobody's car would start, and they recalled the recall! My passat was hooked up for a full day directly to VW tech from the dealer and they couldnt get it to program. They were at the point of replacing the ecu (wish we did). My thoughts were, looking at Diesel Gate, was this was very first sign of "reverting back mode" but nobody understood what they were seeing. Anyway, it was not a good recall for me!

Ccyt · April 21st, 2019, 17:37

Wow this is really amazing. But how you guys know where to put a number that will modified that specific function wow you guys r wizards!!! Really Really good explanations top of the line

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1854sailor · April 22nd, 2019, 08:27

Just go to the Wiki page on Ross-Tech's website. Coding is explained. The first thing that you should do with VCDS, if you haven't already, is to run a full Auto Scan to get the baseline information on your car. That will save all of the existing coding so you can refer to it if you mess something up and need to restore it.

Quote:

Originally Posted by Ccyt

Wow this is really amazing. But how you guys know where to put a number that will modified that specific function...

04colyZQ8 · August 15th, 2019, 11:22

Mmm I’m confused how do I set the ok temp of the glow plug time? Do you need to manually extend the glow plug time per degree of Celsius? I’d need a pot resister wired in the cts? And take several hrs to hot each coolant temp 5, 6, 7, 8c, etc.. and individually change them to 36700?