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Discussion Starter · #1 ·
Hi

I own a GT TDI 150bhp and have done for approximately 6 months, but recently with the slightly colder weather I have experienced some starting problems. Firstly I never get any problems whilst the engine is warm, it is always when the car has been left for more than 8-10hours without being started. I initially thought it could be the glow plugs but I have tried turning the ignition on and off a few times to heat the glow plugs but still experience the problem and makes no improvement at all.

When I turn the ignition key the engine turns over quickly but fails to catch and start, I have had to keep turning it over for approx 5-10seconds and it sometimes still fails to start. When it does start there appears to be an unusal amount of diesel smoke from the exhaust.

Any ideas / advice will be appreciated as I do not have a clue what this might be. I did a quick search but couldn't find any advice except glow plugs and I don't think it is these.

Thanks
 

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It could still be your glow plugs. If they are knackered then flicking it on and off however many times will make no difference. they're incredibly easy to change on the ARL so at least pull them out and take a look. The glow plugs are only used to heat the cylinder when the engine is cold, when it is warm they are not activated.

The smoke is unburnt diesel which is another common sign of glow plug faliure. By turning the engine over and over you are generating the heat needed for the compression, which is why it will start eventually...sometimes!
 

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Take each glow plug out, earth one part and send a live to the tip....quite quickly you will see the tip glow BRIGHT orange, if not / or its slow then theirs your culprit, i have diagnosed many this way.

Also if the tips heavily carboned up is a good sign of an inactive one

That`d be my first step anyway.
 

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Hand book for my 115 says the glow plugs are not used unless you have really cold weather (-10 Deg C etc) certainly not the cool conditions at the minute.

Still your diagnosis seems to point to these??????????

How many miles does the car car have on it? (Cold compression problems maybe?)
 

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Discussion Starter · #5 ·
Thanks for your suggestions, I will take a look at the glow plugs when it stops raining.

Paul, the car has done 52000 miles.
 

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I've had 2 glow plugs changed on mine on separate occasions, they went and the engine management light came on & "emmisions workshop" on the display, however mine still started fine, must have heated3 cylinders rather than 4.

Not sure whether I have helped eliminate anything here!
 

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It could still be your glow plugs. If they are knackered then flicking it on and off however many times will make no difference. they're incredibly easy to change on the ARL so at least pull them out and take a look. The glow plugs are only used to heat the cylinder when the engine is cold, when it is warm they are not activated.

The smoke is unburnt diesel which is another common sign of glow plug faliure. By turning the engine over and over you are generating the heat needed for the compression, which is why it will start eventually...sometimes!
I think this might be a silly question, but won't the glow plug light stay on if one or more is not working (drawing current)? Wouldn't the ECU detect sporadic voltage drawing?
 

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Didn't do anything like that on mine, the Glow plug light came on as normal (for about 2 seconds) - VW in Halifax just said it was a wiring fault in the glow plug and changed it under waranty.
 

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Discussion Starter · #9 ·
Thanks for your ideas so far. I have now disconnected the glow plugs and checked them all individually, they all seem to be quite black on the ends.

I was unable to get any of them to glow, therefore I attached the positive of an electric meter to the wiring and then the other side to the negative of the car battery. I did not get any voltage at all across this.

Therefore I suspect that it could be a fuse to the glow plugs, any ideas where it might be? somewhere in the engine bay?

Also I have had no warning lights illuminate and the glow plug light normally lights for a few seconds on start up and no flashing.

Thanks again
 

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Sods law talking about this thread my emissions workshop light came on again!! My car is back in next Friday to get looked at. Its really starting to wind me up. They have changed 2&3 cylinder glow plugs, so I've told them if its the same problem then I want the other 2 changing so I practically have a brand new set.

Hopefully this will resolve my problem. Its frustrating as it wastes my time & the dealers + my fuel taking the car there and back. They should have changed all 4 when the issue first arrised.
 

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i had same prob last week..on 3 mornings...

Since my Glow plugs had been changed 2 months ago i changed the battery,

ALTHOUGH I HAD IT CHECKED AND IT SHOWED OK ON METER.. my original battery was factory fitted and my car is a 2000 model..so as the cold weather is creeping in i knew its gonna give in..6yrs is long enough for battery life..

AND GUESS WHAT ????? ITS BEEN STARTING UP FIRST TIME FOR 8 DAYS NOW.....
 

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Hmm, usually for a PD engine to not start with faulty glowplugs it would have to be very low temps, id check the coolant temp sensor too,  The glow plugs activate when the coolant temp goes 9 degrees and below, its mostly for emissions.
 

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Discussion Starter · #15 ·
Update...I have changed the glow plugs and I initially thought this had solved the problem. However, this is very odd when the outside temp is approx 0 degree celcuis it started no problem.

I went out to the car today and it was 10 degrees but it started on the turn of the key but splutter and stopped almost immediately. I then tried starting it again and it just turned over for approx 10 seconds and eventually caught and started with the big cloud of smoke.

Any ideas what next, micky mentioned the coolant temp sensor. Any idea on the location of it? Any pics would be appreciated? [:^)]
 

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hmmm could be. as mentioned they only work at certain temps. if it was reading incorrect the glow plugs may not switch on maybe. do you hav vag-com? you can read the value for the sender and check if the glow plugs are on.
 

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Discussion Starter · #17 ·
Nope unfortunately I don't have Vag-com, maybe I will have to try and find someone nearby with vag-com as my next idea.

Unless there is anything else that could be an error, maybe I should buy a new coolant temp sensor? not sure tho
 

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Hi

I own a GT TDI 150bhp and have done for approximately 6 months, but recently with the slightly colder weather I have experienced some starting problems. Firstly I never get any problems whilst the engine is warm, it is always when the car has been left for more than 8-10hours without being started. I initially thought it could be the glow plugs but I have tried turning the ignition on and off a few times to heat the glow plugs but still experience the problem and makes no improvement at all.

When I turn the ignition key the engine turns over quickly but fails to catch and start, I have had to keep turning it over for approx 5-10seconds and it sometimes still fails to start. When it does start there appears to be an unusal amount of diesel smoke from the exhaust.

Any ideas / advice will be appreciated as I do not have a clue what this might be. I did a quick search but couldn't find any advice except glow plugs and I don't think it is these.

Thanks
Almost all diesel starting problems are caused by air getting into the fuel system, things I'd do are;-

1, Check connections at fuel filter, especially the clip in fuel thermostat (this has a rubber 'o' ring that if not seated correctly will let air in the system.

2, Check the security and condition of all fuel lines.

I'd suggest....

The reason it turns over and over then fires is that it is effectively 'self bleeding' the air out of the system which it will do if you change the fuel filter. If sat for a few hours air will have the opportunity to enter the fuel system.

When warm, it is likely there has been little time for air to enter hence the nornal starting.

As Micky has said, the PD diesel needs little or no glowplug time to start, only when it's well below zero are the glowplugs really required.

One other thing it may be (but unlikely) is the tandem pump, tandem as it is both a vacuum and fuel pump. These sometimes fail.

Good luck

And to be sure, I'd change the fuel filter anyway, for the sake of ?15 it buys piece of mind and eliminates it from what could be wrong. It is btw an easy DIY job just pay careful attention to how the 'C' clip and 'o' ring fit.
 
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