Diesel problem

[Aluco]

This problem is on my friends car and he wants some advice so I said I'd ask on here for him as a lot of people are tech savvy and I'm not very good with diesels.

I've copied and pasted what he wrote from an audi forum but it seems fairly inactive and he hasn't had a response yet.

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Hi there, new guy here.

Basically I've been having a massive problem with my A3 recently. It sputters when driving (sometimes at idle) and half the time cuts out usually followed by a large plume of white smoke and a burning smell. It's only began to happen within the past 3 weeks however it's ridiculously dangerous. It feels as if not enough fuel is getting to the engine for whatever reason. I've been through injector changes, cleaning valves, fuel additives and changing looms but nothing seems to be working.

There's also a ringing from the EGR valve after it's stalled and only extinguishes after unplugging two connections to it.

I've been looking everywhere for a solution, the most common ones coming up are injectors, mass air flow sensor, fuel pump-- all I've looked at.

It's an Audi A3 2.0tdi 170bhp 08.

Thanks in advance,
ANPM.


Anyone any ideas? We've got an injector to change on sunday it's already had 1x changed by a garage and he gave us a graph showing cylinder 2 & 4 injectors had fluctuations on them. (4 was changed we will be changing 2 this weekend) I also said it could be a problem with the fuel pump.

Any thoughts?

Cheers

 

[Dan@SJM]

Tbh that's bordering on a turbo failure.

 

[Aluco]

What makes you say that?

 

[Snake182]

What makes you say that?

Agree with Dan@SJM tbh, if its pluming white smoke and down on power/spluttering id be checking the turbo, remove the turbo intake pipe and (with the engine off) check for excessive play in the turbine/bearing/shaft. There may be a tiny tiny amount of play which would be normal but it should be hardly noticeable ( due to the design as the shaft 'floats' on the thin layer of oil when running), also check the condition of the turbine blades. Seen lots of VW/Audi turbo failures.

 

[Aluco]

Couldn't over fueling cause the smoke? It plumes at idle and obviously turbo isn't active until 2kish reva

 

[Aluco]

It stalls at idle why would turbo cause that?

 

[Snake182]

Turbo doesn't need to be boosting, if the shaft bearing seals have gone then it will leak oil into the intake even on idle. Over fuelling on a diesel normally creates a pale blue-ish smoke, not white.

 

[Dr HMS Derv Destroyer]

Turbo.

if it's damaged , restricts airflow into engine - stall

i should know when mine had f**ked up. Ran crap, cut out randomly , stalled on idle unless revs kept up. Finally went and it was like a old massy coming out back lol

loud turbo whistle or turbo ' screaming ' is usually heard I would of thought

 

[Aluco]

Turbo.

if it's damaged , restricts airflow into engine - stall

Sorry for being persistent but want to be sure cos these turbos are expensive...

Plugged the car into VW garage laptop and no faults codes present. Wouldn't this bring up a fault code if the turbo was damaged?

 

[Snake182]

Turbo.

if it's damaged , restricts airflow into engine - stall

Also theres a chance theres a second fault, stalling on VW/Audi is normally caused by a faulty throttle body unit, also very common but this should produce a fault code.

 

[Snake182]

Sorry for being persistent but want to be sure cos these turbos are expensive...

Plugged the car into VW garage laptop and no faults codes present. Wouldn't this bring up a fault code if the turbo was damaged?

no

 

[Aluco]

arse

(Not you, the car)

 

[Snake182]

arse

(Not you, the car)

Lol, check the turbo for play in the shaft first mate (before spending £££). If its free from play and the turbine looks in good shape then it may not be that. 99.9% of knackered turbos will have huge play in the shaft and can be easily checked.

 

[AlexW]

Just get the intake pipe off the turbo and feel the turbo, it'll tell you straight away, rather than messing about changing stuff etc.

 

[Dr HMS Derv Destroyer]

Also theres a chance theres a second fault, stalling on VW/Audi is normally caused by a faulty throttle body unit, also very common but this should produce a fault code.

Assuming the car is a 2.0 TDI CR engine. They seem to be common lately.

The older 2.0 tdi PD engine didn't have a throttle flap (I think ) been ages since I've worked on one

 

[Snake182]

Yeah, quite a lot of them to have them. If the engine code is BMN (170bhp) then it may have one fitted.

 

[Aluco]

Its the PD engine 08 reg car sportback 170bhp