A3 2.0 TDI, difficult starter

[timcoupe]

Hi All,

I've had an '05 2.0 TDI for around a month and it always seems to struggle to start when it's been raining. It will attempt to fire up quite quickly, but will only start proper on the 3rd / 4th attempt. I am waiting for the preheat lamp to go out each time.

I've got an AA warranty, so if it is something serious(ish) I'll be able o get it sorted, but wondered if there were any common things to look at before booking it in.

Thanks.

Tim.

 

[NHN]

I would say glowplugs or coilpacks at fault, but change the plugs 1st mate as if engine is turning over but not starting its unlikely the starter motor, maybe damp in the cylinders, but plugs 1st call & cheapest.

 

[JST_A3]

I would not expect the pre-heat lamp to show at all unless the temperature is very low. If you are seeing the lamp then it could be the temperature sender unit giving an incorect signal to the ECU. This would mean that too much fuel would be injected and starting may take longer. Have you seen an increase in black smoke from the exhaust when it does start?

 

[timcoupe]

I'll look at getting the glow plugs changed first then - the cars done 90k and looking through the history it looks as though they haven't been swapped before.

I don't notice any black smoke at all, hopefully it will just be the plugs.

Is there a guide somewhere for changing the plugs?

cheers!

Tim

 

[NHN]

the heater coil icon shows up most times even for a split second so this isnt an issue, if its on a boiling hot day & its on for number of seconds then I'd think about issues, but seems like its not your problem, plugs would have been changed within 90k for sure, probably 2-4 times depending on your cars service plan, I think they are every 20k, but it wont harm you to change them anyway at 90k & see if that fixes, if not then coilpacks next, I 'm wondering if its getting some damp in the cylinders somehow which inturn would delay start no??? anyone add comments to my theory???

 

[moschino]

Not sure why you would change the Glow Plugs every 20K ?
Spark Plugs yes but Glow Plugs?

You can remove the Glow Plugs and test them with a multimeter, should give less than 1 Ohm.
The other thing to check, is there any corrosion on the feed to the Glowplugs? This can cause High resistance and prevent the plugs from operating correctly.

Coilpacks? On a Diesel?
I thought you only had coilpacks on petrol engines?


Does the car start without problems in the morning when it hasn't been raining? If so then it is unlikely to be the glowplugs.
I will be interested to know what resolves this issue.

 

[NHN]

Learn something new everyday, so what connects to the glowplugs to power them up then, surely it has a similar method for power, something plugs into them to provide power somehow no?

 

[timcoupe]

Will be looking into this further over the next few weeks, so will let you guys know the outcome.

Thanks for the replies.

Tim.

 

[timcoupe]

Hi all,

Just a quick update, I had new glow plugs put in yesterday - needed to leave the car overnight as starting problems are from 'cold' only. Tried this morning, turned over fine, fired up, and then stalled... started fine on the second attempt.

So it seems that the problem is still there, what should I try next?

Thanks.

Tim.

 

[giblets46]

I have a similar problems, but even at the moment when its 15-20c, first time I start it in the day, it has real problems starting, stutters for about 2-3secs then is fine. Will the glow plugs be a prob even at that temp?
Though mine is slightly different 2yrs, 80,000miles.

 

[xs2man]

Think I need to change the glow plugs on my A3. Is there a guide anywhere?

 

[jameshughes1974]

How old is your cambelt?
There is a measurement called the torsion value on these which is adjusted on the cams.
An old belt may have stretched knocking the value out.
Timing of course can make a car hard to start.
Mine was tricky until I did the belt and adjusted it through vagcom.
In fact i was fairly unhappy with its starting compared to the older 110 BHP cars until I did the belt.
At a later date i took the starter off and cleaned and regreased the inards which made it better again.
Some people have had new starters but i bet they just needed a clean inside.
Considering the compression in a diesel engine the starters arent that big on the 2.0 diesel.

I also find it starts better if i let it crank once then find its own way to idle rather than holding the key in the starter position for 3 or 4 turns

 

[jameshughes1974]

I also doubt its your glow plugs as these cars use them more for emissions purposes its only when you get to single digit temp that they come on more to aid the starting
beware that the glow plugs in your a3 arnt the old 12 volt type - i think its more like 6 (off the top of my head) and they are pulsed on and off so ye old 12v test will lead you down the garden path.

The thing that does stand out is you say this is only does it when wet - which makes me think rain water is getting someware it shouldnt

 

[jameshughes1974]

ha have just seen the date on the original thread

 

[NHN]

Reference starters, I've read bit up on these & the starters seem to be effected by heatsoak imho from the gearbox which has been around for years especially on VAG cars funnily enough, I took a few apart, the internals certainly didnt need greasing at all, just over a period of time the coil internals just become well prone to effects of the heat IMHO, a new starter which I believe has been revised, starts a hell of alot better, very quickly & tbh wasnt very expensive considering, certainly one thing I would check, aswell as the things you mention.