A2 TDi 75 160k miles, smokey on cold start. Is it normal?

philward

Member
The MOT tester describes my car as being as clean as a whistle. However he only gets to test it hot.

Cold start is very different, lots of smoke is produced. Hot start is fine. The car has been stood for about 4 weeks and this is how it starts. Yes I have been driving an auto and forgot the clutch :rolleyes:. The smoke though, is it normal? If not what could it be, valve seals? Something else?

 

audifan

A2OC Donor
Check the glow plugs are working correctly. Suspect it is a bit of unburnt diesel as the engine is cold. If you cycle the glow plugs twice before starting does it improve. Lack of use not good. Did not sound like it was turning over fast either. Good battery and all power and earths good?
 

philward

Member
Check the glow plugs are working correctly. Suspect it is a bit of unburnt diesel as the engine is cold. If you cycle the glow plugs twice before starting does it improve. Lack of use not good. Did not sound like it was turning over fast either. Good battery and all power and earths good?
I’ll try cycling the glow plugs. Could one have failed?
As far as I know earths are good. Battery has been sat for weeks but will try a fully charged one.
 

audifan

A2OC Donor
When you check / change the battery it is very important that the battery terminals are clean, the leads are firmly clamped onto the terminals and the little black block to the left of the positive terminal is tightly bolted to the positive clamp and all the internal connections inside the block are tight. Be careful not to short these to earth while tightening them!!! The other often problematic lead is the starter to body earth just below the ABS pump / left head light, not only can it be loose, but can often be corroded internally so just checking it is tight is not enough. Many of us run a secondary body to engine earth as an insurance. Glow plugs do fail but it is obvious the car is only running on 2 cylinder when that happens, but if there power supply is too low they are not getting hot enough to warm the cylinder to burn all the fuel. When the engine is warm the glow plugs are not required and the engine will start with no or far less white smoke.

Strangely enough the one earth lead I would have though to cause more problems does not appear to be causing any. That is the one that runs from the battery negative post to the chassis just in front of the left rear wheel.
 

nod

Member
my 2001 tdi does this smoking on cold start , and I have a glow plug fault code when scanned (can't remember the exact code), no lights on the dash but the fault is there when scanned - on my 'to do list'....bit lumpy and smokey on start up, then fine.
i'll see if i can find the code...

edit: the code on mine is p0684 glow plug control module (J271) - implausible signal .
 
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Olerype

Member
Mine has been like that for 40kmiles now. Probably oil residues it burns off after being standstill. Leaky valve seals if guessing. Nothing to do is my 50 cent.
 

philward

Member
Mine has been like that for 40kmiles now. Probably oil residues it burns off after being standstill. Leaky valve seals if guessing. Nothing to do is my 50 cent.
That was my thought, valve oil seals letting oil into the engine when it has been stood for a while. However I’m going the investigate, glow plugs, earths etc now as the primary suspects.
 

Olerype

Member
50 cent the smoke is not related to glowplugs or earth. Be careful with glowplugs; the threads are easy to destroy
 
The MOT tester describes my car as being as clean as a whistle. However he only gets to test it hot.

Cold start is very different, lots of smoke is produced. Hot start is fine. The car has been stood for about 4 weeks and this is how it starts. Yes I have been driving an auto and forgot the clutch :rolleyes:. The smoke though, is it normal? If not what could it be, valve seals? Something else?

Cold start - smoke for 4 seconds - would have thought normal anyway - 130,000 miles ( do change gearbox oil on A2 - nowt to do with smoke though )
 

Howey

Member
Are you sure its not steam from condensation?
When i first bought my A2 i was following it home and stopped my mate within a mile of leaving the sellers house due to the steam/smoke!
Upon removing the bonnet all looked well.
Only once i had the car on the road and gave it a good long run did it clear!
The injector harness may be worth removing and tightening the connections
Does it use any oil?
 

philward

Member
Finally got a chance to look at this starting problem. I connected the battery earth direct to the engine via a jump lead. Engine exploded into life with very little smoke. Prime suspect is therefore the engine earth strap. Which I can’t find. Anybody got a part number; 2003 TDi 75? Thank you.
 

philward

Member
Are you sure its not steam from condensation?
When i first bought my A2 i was following it home and stopped my mate within a mile of leaving the sellers house due to the steam/smoke!
Upon removing the bonnet all looked well.
Only once i had the car on the road and gave it a good long run did it clear!
The injector harness may be worth removing and tightening the connections
Does it use any oil?
It doesn’t use much oil at all. Injector harness was sorted a couple of years ago. Its not condensation, not noticed any dripping from the exhaust.
I think it is the engine earth strap.
 
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