Not Audi but VAG passat 1.9 tdi 130 2004

[K7ERG]

Hi all

Looking for some guidence regarding a problem I have came across on ny brothers car. There has been various codes on this and alarms on the dash. first being code 401. The alarm on the is "emission workshop". I can clear the codes but come back after a few sort journeys.

What I have done since is cleaned the inlet manifold, egr valve and egr pipe to valve from exhaust manifold. There was a lot of build up.

Refiitted reset code again

Few journeys same again.

Checked under bonnet as sounded like a leak. Traced it to the airbox which had backpressure. I have never came across this. I would also say there is some back pressure from oil filler cap also.

Going to check breathers but not sure if cat maybe blocked or something else.


Any help or suggestions welcome

Craig

[Monkeymagic]

Exhaust valves not sealing seen it before . Does it sound kike compression being forced back into air box.
Had it once just before the head fell off an exhaust valve

[Monkeymagic]

Whatvcds codes are you getting

[Monkeymagic]

I just thought does the idle fluctuate. I have had failed n18 valves causing the anti shudder/egr to open and shut randomly that causes a sound of air wooshing.

[K7ERG]

Idle is ok as it should be. The small actuator on throttle body if manually moved stalls the engine. Engine seems to run ok but mpg is around low 30. It's not driven hard.

Code is p0401 that came up.

Not sure if it's the egr that is causing it or what controls it.

Hope it's not valves.

Also head cams wear.......

[Monkeymagic]

You needs vcds to see whats going on with egr

[K7ERG]

The only code is P0401. Exhaust Gas Recirculation Flow Insufficient Detected.

Apart from that the dash has "emission workshop" displayed on start up then disappears.

[Monkeymagic]

That should have a mechanical egr on it. I cant think ive seen one fail.
The later electric ones do and bring on the emissions workshop.
What engine code is it ill look at some diagrams

[Monkeymagic]

Just thought it the anti shudder flap operating eg shutting when you turn the engine off and re opening moments later.
You really need vcds to do output tests. Measure the maf reading etc.
Also check the egr with a mityvac.

[K7ERG]

The small black actuator valve on the throttle body /egr valve makes a difference if moved but not far enough to stall the engine. Will have to put a boost gauge on to see what pressure is there. The engine also is quieter. Less back pressure in airbox and oil filler cap.

[Monkeymagic]

So its stuck open? Those little black diaphragms split internally.

[K7ERG]

Ok will try find a replacement to see if that helps.

[Monkeymagic]

Checj it first put vac pipe on suck it and stick tongue on. If flap doesnt open or shuts then diaphragm split. Mityvac will be easier if you can borrow one

[K7ERG]

Will try tomorrow report my findings.

Cheers for the help

Craig

[K7ERG]

Today went to u pull it for some parts.

First Thing changed on the engine was the actuator on the throttle body. Which made no difference.
Changed the solenoid valve on the airbox which made the actuator on throttle body operate.

Engine is still doing the same with the back pressure through the airbox.

So changed the solenoid with black top under plastic pipe.

Still the same.

I located the other solenoid valve with the white top but not changed it yet.


I have bought blanking plates for egr delete.

Thinking the cat is ok as the engine pulls fine.

Thinking maybe vanes are stuck on turbo.


Any suggestion welcome

Craig