Please can anyone advise as to where the Vacuum pipe goes from the EGR Valve.... to where? 

When I replaced the EGR Valve the Vacuum pipe was very brittle and snapped when I moved it out of the way. The other end has a round plastic end but I cannot see where it should attach to? 

It isn't a vacuum pipe and it doesn't go to anywhere. That round thing is a tiny filter which allows a small amount of clean fresh air to the valve. 

It's a 1.4 16-valve engine presumably?

 

Why did you replace the valve?

Edited 10 June, 20187 yr by Wino

Hi wino, thanks for your advice. I have since seen this on a you tube video too now. We changed the valve because for over a year now the car had had EGR fault codes and my local garage has managed to reset the fault display. I also gave the throttle body a good clean out too. This was really clogged up. 

Car now runs ok but warning lamps still on. I'm guessing the ecu will need resetting again to clear the warning lights. 

If this fault persists I'll be suspecting the throttle pedal sensor. Do you have any other suggestions? 

Cheers. It is the 1.4 16v petrol. 

Which fault codes were showing prior to EGR replacement, and which are present now?

Did the engine ECU get adapted to the new valve when it was fitted? (simple process done with VCDS, or VW-group equivalent tool, that fully opens and closes the valve so that the ECU can learn the resistance values of the potentiometer in the valve at these two positions).

 

What's your approx location?

Good morning Wino,

Thanks for your help with this ....most appreciated.

As I write my son is arranging to take the car to a local garage in Yelverton, which is in Devon near to Tavistock. He is hoping they will have the equipment needed to do the reset etc. Once that is done we are hoping all will be good, but if not at least it will show up another error code. Unfortunately I don't know what the previous error codes were.

Cheers. Bob.

Morning Bob. Unfortunately you're not exactly 'round the corner' or I would have offered to scan it for you, and try the adaptation.

Best of luck, and please let us know the outcome.

I am just 'round the corner' in Plymouth. At home today but off on holiday tomorrow. I'm waiting for a delivery from Hermes but once free I could come out  with VCDS and scan, adapt EGR and throttlebody and see what codes you have. No idea yet when the delivery will come. Had a very similar 'EGR light' on daughters 1.4 16 valver which eventually was cured by removing the manifold and cleaning and sealing every gasket, O ring and pipe. Never did identify the actual air leak but by sealing everything I managed to cure the problem.

 

How do people usually get in touch? pm me a phone number?

Edited 12 June, 20187 yr by LB123

Hi Wino and LB123,

 

Apologies for the delay in replying to you.....but....the car was checked and the error codes reset to no avail. Then a compression test was done and no compression found on one of the cylinders..! Car now scrapped and gone to that Skoda yard in the sky.

Many thanks for your advice. best wishes. Bob. 

Sad ending to the story, but thanks for the update, I wonder what went wrong with that cylinder, cracked valve maybe.

9 minutes ago, Wino said:

Sad ending to the story, but thanks for the update, I wonder what went wrong with that cylinder, cracked valve maybe.

 

In all these years this is the first 1.4 16V to suffer such a failure, they're incredibly robust, I thrashed mine ruthlessly for 7 years regularly entering the red zone on the tacho without any mishaps at all, in fact I just sold it to a family friend since it was just sitting in the yard looking sad after the ex-wife gave it back to me. 18 years old and still going strong.

Good to hear.

It's an MLS head gasket isn't it, so relatively unlikely to be that? (especially with no coolant loss mentioned).

Any other theories? Ring failure?

54 minutes ago, Wino said:

Good to hear.

It's an MLS head gasket isn't it, so relatively unlikely to be that? (especially with no coolant loss mentioned).

Any other theories? Ring failure?

 

I'm at a complete loss unless it's dropped a valve or holed the piston, it can't be rings, you'd still have compression even with a stuck or broken ring.

 

No compression would mean it was running on three so one of the fault codes would have been persistent misfire on that cylinder.

Edited 21 June, 20187 yr by sepulchrave

2 minutes ago, sepulchrave said:

No compression would mean it was running on three so one of the fault codes would have been persistent misfire on that cylinder

 

Yeah, I was thinking there'd be more than just EGR codes.

 

@Bobewens Hey Bob, any chance you could nip down that scrappie with some tools and whip the head off the engine for a look?

On 10/06/2018 at 16:44, Wino said:

It isn't a vacuum pipe and it doesn't go to anywhere. That round thing is a tiny filter which allows a small amount of clean fresh air to the valve. 

It's a 1.4 16-valve engine presumably?

 

Why did you replace the valve?

I can't seem to find explanation as to why is there a hose connected to my air intake (1.2 12V Fabia MK1 engine). 
From what I've seen EGR valve on this engine is a computer operated solenoid, so it doesn't require a vacuum hose.
Why does it require a connection with airbox? Is there a some kind of sensor within the valve?
What would happen if it were disconnected?

If disconnected you will just get a small amount of unfiltered air going in, instead of filtered air. That could contain dust/particulates.

 

It connects in on the solenoid side of the EGR valve stem, bleeding a small amount of air down between valve stem and valve guide. 

Not too sure exactly why this is needed, possibly a cooling function; possibly to prevent exhaust gas soot from clogging the stem/guide clearance, maybe both.

1 hour ago, Wino said:

If disconnected you will just get a small amount of unfiltered air going in, instead of filtered air. That could contain dust/particulates.

 

It connects in on the solenoid side of the EGR valve stem, bleeding a small amount of air down between valve stem and valve guide. 

Not too sure exactly why this is needed, possibly a cooling function; possibly to prevent exhaust gas soot from clogging the stem/guide clearance, maybe both.

I saw that some EGR valves cool the exhaust, although it didn't specify if they use clean air to do it or some kind of liquid cooling. 
I would say it's just sucking the air in to cool the valve in this case. I don't like the fact that it is so hard to get the exact datasheet on each of these parts. 

I've seen some info on it in one of the self-study programmes for a different engine, I think.  Remembering which one may be a challenge. 

EGR coolers use liquid cooling. Engine coolant. Only on diesel Fabias, and only later built ones.

Found this in the document about AUA/AUB 1.4 engines:

 

 

 

Pressure balancing function, apparently.  

2 hours ago, Wino said:

Found this in the document about AUA/AUB 1.4 engines:

 

 

 

Pressure balancing function, apparently.  

Anyways...
I decided to disconnect the EGR connector to the ECU. 
I left it stuck on the valve, It's just not clicked into place (so I could easily click it if necessary). On my Fabia it didn't trip the check engine light, but my scan tool detected the code. 
Since I don't really care about the code, I will leave it disconnected for a while to see how much improvement I'll get. I will plug it back in before the emissions test lol. 

Improvement in what?

2 hours ago, Wino said:

Improvement in what?

Idling and mid range power, and hopefully as a result, a lower fuel consumption. 

EGR is apparently closed only when you give full throttle and just before stalling. I want to be able to cruise at 3000rpm with still some decent power to it.
I don't want to bash my accelerator to the floor (to force the valve to close) every time I want to accelerate. It really depends on the engine, and how well the system operates.

I wouldn't do it on a newer vehicle, but my gut is telling me that these cars are not tuned very well, and they rely too much on unburnt gasoline too much for cooling down the exhaust. I think that gasoline pollution is much worse than some extra NOx gasses, but we can't argue with the clueless people who make the regulations. It makes sense for diesels because the amount of NOx can literally burn your lungs in the city. But I've never seen a gasoline engine with those amounts of NOx gasses. As a greenhouse gas, I don't consider it to be worse than dumping raw gasoline into the atmosphere.

I don't think EGR is active at low rpm like idle speeds on petrol engines.

I'll do a log on our 1.2/12v later to see, but certainly on my 1.4 Polo, below 1500rpm the EGR closes completely, I seem to remember.

On petrol engines at cruising speeds EGR improves fuel consumption by reducing pumping losses.

Yes, I know that. I just don't really trust the old software.

 

That's why I'm going to test it myself and see.

 

I will also track the air temperature (however I'm not sure if the temperature sensor is aware of the EGR) . 

But there is one problem with the EGR regardless of it's net effect and that is responsiveness.

 

It takes a second or two for the gasses to clear even if the EGR is suddenly closed by the computer. 

 

I don't think that disconnecting it will improve fuel efficiency, but I do think that a resulting style of driving could.