2014 passat 1.6tdi knocking/vibration & some smoke , any ideas? -- SOLVED.

Effician

The story since Friday morning when it failed to start ( had previously been working fine) , put a charger on it for 10 mins & started fine & all good.  Drove 20 miles to put a good charge in it & worked fine , checked battery voltage when back home & it only read 12.18v so arranged collection of a new agm today 10 miles from home, car started fine this morning & drove the 10 miles there fine & left car running while collecting.

On the way home it didn't  seem quite right after the heater went on low or 5 mins before switching it off. then 5 miles from home it stalled at a junction , lots of dash lights came on then all but the tyre pressure went out , the electric handbrake seemed odd as well for a minute after starting. It fired up straight away but a knock had appeared most prominent when accelerating between 1000 & 2500rpm, there was a gassy smell as well all the way home, was half expecting not to make it.

Checked the battery at home & only 11.89v so promptly fitted the new one but still the same knock & some smoke from exhaust as well as some very small wiffs of smoke from the exhaust manifold to turbo .

Checked or codes with neighbours basic obd11 but nothing there, disconnected battery for 1hr which cleared the tyre pressure light but knock still the same.

I can't help thinking the dead battery has lead to this but i suppose it could be coincidence.

Have trawled through youtube for similar situations but am at a loss so as hoping some of the knowledgable folk on here may have some ideas.

Ayr_Rage

If the heater stopped working then that suggests the coolant has escaped somewhere and the smoke is now due to something possibly being seriously cooked.

Check the coolant level in the radiator and expansion tank.

You could also have run out of oil and the turbo has or is the process of bearing failure causing smoke and the bottom end bearings are shot and knocking.

Effician

I switched the heater blower ( they work fine) off to save battery , coolant level fine & new oil 2 months ago still at correct level

facade

Has the alternator set on fire, or fallen apart or something?

When the engine is running even with a dead battery there should be no need to turn things off to save electricity.

IIRC, the vacuum for the brakes is from a separate pump, so if the alternator stops the only thing you will notice is electrical failure.

You really want to know the voltage with the engine running.

If the alternator fails so that it overcharges, it will kill the battery and the battery will smell eggy.

paul_c123

If you don't know its scanned the ECU for codes with the basic scanner, then you need to scan it (or have a garage scan it) with something better, to know. 

If there's no codes logged it normally means its something mechanical, not electrical. Engine knock and a gassy smell would indicate this too. Does it now turn over reasonably well (with the new battery)? Or is there an obvious single cylinder compression loss? Does it start? 

Effician

The old battery is 8yrs old & i admit that i didn't check the voltage with engine running but no eggy smell,  new battery measured 12.6v  disconnected & 14.4v when engine running which i think is right for agm bulk charge

Effician

paul_c123 said:

If you don't know its scanned the ECU for codes with the basic scanner, then you need to scan it (or have a garage scan it) with something better, to know. 

If there's no codes logged it normally means its something mechanical, not electrical. Engine knock and a gassy smell would indicate this too. Does it now turn over reasonably well (with the new battery)? Or is there an obvious single cylinder compression loss? Does it start? 

Turns over great & starts instantly with new battery, sounds almost normal at tickover with just the slightest vibration, between 1000rpm & 2500-3000rpm sounds worst,   on the way home for last few miles with old battery it felt almost normal above 2500rpm ish and still pulled ok but smelled gassy.

facade

Does smells gassy mean you can smell diesel?

paul_c123

Could be an injector. It is a common issue on the 1.6TDI

There is an easy way to tell. Disconnect the electrical connection from each injector one by one. The one that DOESN'T affect how the engine sounds, is the faulty one.

Effician

Hard to describe really not oily , not coolant & not sooty but more pungeant than the usual exhaust smell maybe just because more is being pumped out.

I may be clutching at straws but the closest i've found to my symptoms is a guy that had injector problems & even after replacing & coding the issues remained until the ecu went through it's learning cycle through driving.

I'm hoping the ecu just had a brainfart when the car stalled at  low revs at a junction possibly due to the dead battery & it needs a similar learning period with the new battery.

Effician

paul_c123 said:

Could be an injector. It is a common issue on the 1.6TDI

There is an easy way to tell. Disconnect the electrical connection from each injector one by one. The one that DOESN'T affect how the engine sounds, is the faulty one.

I've looked at a few injector vids & they all knock quite bad at tickover where mine doesn't ,i'm inclined to think it's more a timing issue but i will try as you suggest tomorrow just to eliminate.