Latest daily shitter VAG TDI.

[bigstraight6]

Hello all, a few weeks ago literally just before going on holiday (by mistake of course!) an old friend turned up on the doorstep, “are you still interested in the Golf”.  Now, I’ve made it clear to said friend that when it came to parting company with the car that he’d owned for 12 years I wanted first refusal and I naturally bought it there and then for a small amount of monies.

The car was just about to be sans MOT, so a hastily arranged appointment led to a failure on deteriorating dust caps on lower ball joints and track rod ends and emissions. Crappy suspension parts replaced, glug of Millers diesel eco boost and a ragging gained an MOT pass.

On return from holiday I started the car and it was initially quite smokey, which cleared after another ragging, but the Smokey start up still persists. The car starts instantly and pulls really well (1.9TDI by the way) the smell of the smoke suggests unburnt fuel, me and a friend with a diagnostic plug in are having a look this weekend, hopefully no drama’s! 

 

 

 

[stuboy]

20 minutes ago, bigstraight6 said:

Hello all, a few weeks ago literally just before going on holiday (by mistake of course!) an old friend turned up on the doorstep, “are you still interested in the Golf”.  Now, I’ve made it clear to said friend that when it came to parting company with the car that he’d owned for 12 years I wanted first refusal and I naturally bought it there and then for a small amount of monies.

The car was just about to be sans MOT, so a hastily arranged appointment led to a failure on deteriorating dust caps on lower ball joints and track rod ends and emissions. Crappy suspension parts replaced, glug of Millers diesel eco boost and a ragging gained an MOT pass.

On return from holiday I started the car and it was initially quite smokey, which cleared after another ragging, but the Smokey start up still persists. The car starts instantly and pulls really well (1.9TDI by the way) the smell of the smoke suggests unburnt fuel, me and a friend with a diagnostic plug in are having a look this weekend, hopefully no drama’s! 

 

 

 

look good

[Popsicle]

Good to see a fellow 1.9 PD user - it looks remarkably straight and clean, particularly the front arches.

When mine went through a smoky stage it turned out to be the turbo actuator was stuck, I think it causes too much fuel/not enough air, which causes the smoking. Mind you mine was sometimes down on power at the time, as yours has plenty of power, ignore me I'm probably barking up the wrong tree.

Welcome to the wonderful PD world though.

[bigstraight6]

To start with I thought I’d have a look at the air filter, it’s a bit grubby but I’ve seen far worse but I will grab a new one anyway. Not convinced that this is the source of the issue, what do you think chaps….

[beko1987]

No probably not, I've ran worse on cars that have been totally fine. 

How far upstream of it can you go? Blast the maf with brake cleaner and any other sensors you can take off. Take each big pipe join apart and clean the mating faces and re do the clamps (assuming jubilee clips and etc). Won't hurt and you might catch a folded up seal or something letting air go where it shouldn't. 

Plus as you go you can study the engine bay and work out what needs to come off to go deeper and investigate. Any telltale patches of oil/oil spray in a random location on the engine? 

[Popsicle]

13 hours ago, bigstraight6 said:

To start with I thought I’d have a look at the air filter, it’s a bit grubby but I’ve seen far worse but I will grab a new one anyway. Not convinced that this is the source of the issue, what do you think chaps….

That doesn't look too bad, so unlikely to make a difference, but its still good to change it.

I change mine every 20k ish, this is a 20k one v a new one.

 

[bigstraight6]

On 12/09/2026 at 17:35, beko1987 said:

No probably not, I've ran worse on cars that have been totally fine. 

How far upstream of it can you go? Blast the maf with brake cleaner and any other sensors you can take off. Take each big pipe join apart and clean the mating faces and re do the clamps (assuming jubilee clips and etc). Won't hurt and you might catch a folded up seal or something letting air go where it shouldn't. 

Plus as you go you can study the engine bay and work out what needs to come off to go deeper and investigate. Any telltale patches of oil/oil spray in a random location on the engine? 

Thanks mate, I’m getting stuck into it more now and and hoping it’s not going to be a big issue as the car drives and pulls really well…

[MrBig]

Is that Millers stuff like the old days of dropping a bottle of Redex in the car? You have to take it out and give it a long hard kicking for it to drag all the crap through and burn it off before the smoke dies down?

[beko1987]

I've had good experience with Forte diesel injector cleaner. My 2.0dci gooner2 would go into limp mode if I boosted too much from cold and a bottle of the above down it's tank stopped it for a reliable many months at a time 👌 

Keep meaning to throw some at the qashqai, currently it might be cheaper to run a full tank of it neat than actual diesel 🤔 

[Talbot]

On 10/09/2026 at 21:35, bigstraight6 said:

quite smokey,

What colour smoke?  Will tell you a lot about the issue.

If it smokes on cold start and then clears quickly, it's very much possible it's leaky valve stem oil seals that are letting a bit of oil into the inlet/exhaust ports when stopped, which then either burns off (inlets, sometimes blue) or just smokes off (exhausts, usually white) on startup.  Which can smell a bit oily/fuelly.

A blocked air filter would produce black smoke (unburned diesel).

[bigstraight6]

An update, my mechanic friend thinks it’s an injector issue but the sure way to tell is to remove and test them which I don’t really want to get into. The fuel filter doesn’t look like it’s been changed in a while so I will do that and run some injector cleaner through it and see what happens, it only seems to smoke on initial driving and then clears, it drives really well so fingers crossed..

[Somerset Suffolk]

any chance its the injector wiring loom inside the rocker cover? this failed on my MK4 PDI and was thought to be injectors - changing the injector loom (cheapish and fairly easy) sorted the miss fire - different model/different symptoms but worth considering ? 

 

good luck

[Pat Earrings]

3 hours ago, bigstraight6 said:

An update, my mechanic friend thinks it’s an injector issue but the sure way to tell is to remove and test them which I don’t really want to get into. The fuel filter doesn’t look like it’s been changed in a while so I will do that and run some injector cleaner through it and see what happens, it only seems to smoke on initial driving and then clears, it drives really well so fingers crossed..

That top casing will look that way regardless how new the fuel filter is. It’s a paper filter that goes inside it. 
 

try a strong injector cleaner as a base line easy attempt but your mechanic mate is probably right, leaky/lazy injector causing it to burn off excess on cold start sounds familiar.

[AnnoyingPentium]

Always liked this shape Golf. Looks a nice one, hopefully you get it sorted soon.

[bigstraight6]

Thanks for all the kind replies dudes, will keep ya all updated,

[bigstraight6]

The latest thrilling update, yesterday I changed the engine oil/filter and fuel filter (which looked pretty awful) and bunged some injector cleaner in it and the situation appears to have improved significantly, I cold started it this morning and normal levels of smoke on an 18 year old VAG TDI were present. The old clacker will now be staying and pressed into daily service….

[Matty]

Relatively simple cars that just do a job are getting thin on the ground. Stick with it pal!

[bigstraight6]

Just now, Matty said:

Relatively simple cars that just do a job are getting thin on the ground. Stick with it pal!

Thanks Matty, I think this old donkey has a good few years left in it yet, especially as I do oil and filter changes every 6 months which I know is way over the top!

[beko1987]

Hopefully that will perk it up! Got any nice long runs to do with that in the system? 

I must buy a bottle of something for my 1.5dci, it's had cheap shit fuel only in my ownership 🤣 

[bigstraight6]

45 minutes ago, beko1987 said:

Hopefully that will perk it up! Got any nice long runs to do with that in the system? 

I must buy a bottle of something for my 1.5dci, it's had cheap shit fuel only in my ownership 🤣 

This recommended stuff seems to have done the trick Sir!

[Dj_efk]

Nice old PD. The filters look normal for a slightly neglected example.

Make sure you use approved 507 oil as shear strength is critical for the cam bearings. I find Quantum is the cheapest in 20l cubes.

Do you have VCDS? Dark art-levels of diagnosis can be done once you figure out how to use the measuring blocks and logs. A very good tool.

i was going to suggest performing a closed-circuit diesel purge using that liquid-moly stuff. That will shift a LOT of crap if it’s never been done.

i switched away from Millers to Archoil as it’s a slightly better formulation, but running either over the long-term will eventually sort your injectors out.