EGR blanked Today!

[Funkyfin2000]

Hi All,

Today on my 2005 FR+ PD 150 i blanked the EGR! hurahhhh!!

After getting piss poor MPG, i thought I would give it a go.

Question, would it be wise to turn it down with vag.com as well?

Also what blocks are best to measure on vag.com for MAF and EGR and anything else useful?

Will report and see how I get on, started it a few times and moved it about and no engine management light as yet

Rich

 

[slick]

Hi All,

Today on my 2005 FR+ PD 150 i blanked the EGR! hurahhhh!!

After getting piss poor MPG, i thought I would give it a go.

Question, would it be wise to turn it down with vag.com as well?

Also what blocks are best to measure on vag.com for MAF and EGR and anything else useful?

Will report and see how I get on, started it a few times and moved it about and no engine management light as yet

Rich

You wont get an engine management light for a while, its only when the O2 sensor in the manifold doesnt match, what it should read with the mixed of exhaust gas air being recycled.
This is where it can start to throw up a fault code on a 150PD.

The question I've still to figure out is, that there is conflicting information on how the anti-shudder valve is coping with it.
I've been told and read on numerous occasions that the butterfly valve on the EGR used to stop the engine without a shudder, is used during normal driving conditions. E.g. on idle the valve is slightly closed to slow down the fresh dense air flow and let in the warmer exhaust air, thus cooling the engine combustion temperature down and also the fuel consumption.
The worry is, that if the O2 sensor is in charge of the operation of the EGR and anti shudder valve, if you block the gases in the EGR, the valve closes more and more, waiting for the warmer air, and as its blocked, you basically starve the engine of air and it stalls, or near stalls, or which point the valve opens again as the ECU is trying to counter act the stall, thus popping up a CEL code.

Sorry it doesnt help answer your question, but this has puzzled me for some time, and wondered if a few more knowledgable members could put light on the situation!?

 

[Funkyfin2000]

Well as you predicted the CEL light is on and off, mainly on.

I have seen no improvement in my poor MPG which gets to 42mpg at the very best, mnostly 35-40mpg which is very poor!!!!

Turning engine off is perfectly fine, not seen any change at all, not rough or anything but the car certainly is much smoother to drive, not faster just smoother.

Could do with the CEL mapped out tbh!

Rich

 

[slick]

Well as i said, the valve is still operational during shut down and start up.

Its the operation during driving that concerns me...

on idle especially, do you notice the engine speed to dip and raise ever so slighty on idle after the engine has reached normal operating temperatures (90)?

 

[glynnd]

if you put a 5mm hole in the blanking plate it lets just enough crap through to keep the light off. Works fine on mine no light!
Glynn

 

[jabbasport]

The light comes on because of the air mass flow readings being higher due to it drawing in more fresh air through the MAF instead of a mix of fresh and recycled gas.

Basically, just a control difference between what the management has been told it should expect and what it actually sees.

Slick: Diesels dont have O2 sensors, please see text above why the fault comes up. ASV isn't used during idle i believe. I have a Jabba removal pipe on my Fabia and the idle is steady as a rock.
Throttle is purely controlled on injection quantity, it doesnt matter how much air is running through the engine.

 

[slick]

Which is just the same as changing the cycle duty on the EGR values via VAGCOM.

I dont understand the point of putting a hole in it, it just means your restricting the hole and the soot will build up under the hole, and could eventually clog it completey, then the light will come up.
Plus if the light isnt on, then its not making a difference to the numbers of EGR values, e.g. letting in the same amount of air, so you might aswell not have the plate at all?

No offence gylnn, but its the way i see it, it aint doing nothing unless it upsets the ECU....
Also you may be making the anti shudder valve actuate more often than before because of the restrcited flow?

 

[jonjay]

The light comes on because of the air mass flow readings being higher due to it drawing in more fresh air through the MAF instead of a mix of fresh and recycled gas.

Basically, just a control difference between what the management has been told it should expect and what it actually sees.

Slick: Diesels dont have O2 sensors, please see text above why the fault comes up. ASV isn't used during idle i believe. I have a Jabba removal pipe on my Fabia and the idle is steady as a rock.
Throttle is purely controlled on injection quantity, it doesnt matter how much air is running through the engine.

TDI's do have O2 sensors I believe.

The EGR valve opens to the exhaust system and the "throttle plate" (as some call it) closes and creates a vacuum which then top up by the increased flow of exhaust gases. The O2 sensor is the feedback to the ECU which controls this.

 

[slick]

The light comes on because of the air mass flow readings being higher due to it drawing in more fresh air through the MAF instead of a mix of fresh and recycled gas.

Basically, just a control difference between what the management has been told it should expect and what it actually sees.

Slick: Diesels dont have O2 sensors, please see text above why the fault comes up. ASV isn't used during idle i believe. I have a Jabba removal pipe on my Fabia and the idle is steady as a rock.
Throttle is purely controlled on injection quantity, it doesnt matter how much air is running through the engine.

So your saying that, if i take a reading off the anti-shudder valve, it will not change until engine shut down or start up?

 

[jabbasport]

I wouldnt have thought so, there's no need for it to operate on idle.

It'd be interesting to find out for sure though by taking some readings

 

[slick]

I wouldnt have thought so, there's no need for it to operate on idle.

It'd be interesting to find out for sure though by taking some readings

Well as there is no meter on the exhaust intake gases, i cant see how the ECU would notice any difference in the readings, as its always feeding fresh air in....
If it had a meter in the exhaust port it could sort the mix out....


It sounded like you was 100% sure it doesnt move in your first post, but not so sure now.
Do you know for sure there isnt a O2 sensor, or that the valve moves during idle to lower the engine temperature or save fuel consumption?

Not picking on you, just the way i read it, was like you sayin you knew the answer for a fact? Do you own a PD150? Only noticed you had a 1.8T IHI on your avatar?

 

[jabbasport]

I'm Kev from JabbaSport, the avatar states we pretty much invented the IHI turbo kit when we put one in a Rallye many many years ago when we first developed a kit.

There definately is no 02 sensor.

I personally own a PD130, which has the same Exhaust Gas Recirculation system and management system (EDC15), and have worked on/ mapped many cars, bother diesel and petrol.

The management notices the readings from the MAF and pulls up a faultcode because instead of pulling in say a 20% exhaust 80% air mix it's now pulling the full 100% through the MAF instead of the 80% if you get me.

This can be noted when lowering the EGR duty cycle in vag-com, you actually see the actual MAF value increase as you reduce EGR duty cycle.

Just to confirm.
The EGR plunger works at idle, recirculating exhaust gas into the engine.
The Anti-Stutter valve shuts when the engine is turned off to choke the engine and stop run-on (which is the judder) when you shut down. It's also supposed to be employed to choke the engine in a hazard situation such as run-on from oil injestion aswel. I'm 98% sure of this, but it'd be nice to hear otherwise and im open to suggestions that's why i wasn't going to completely shoot down your idea of it being utilised during idle to minimise fresh air flow, but i'm highly doubtful.

My car has no EGR plunger (EGR blanked at exhaust manifold) and no anti-stutter valve. Idle is rock solid, the only difference being now is that there's a slight shudder as you turn the ignition off which you'd expect now the Anti-Shudder Valve has been removed.

Thanks
Kev

 

[slick]

Thanks for your input Kev.

As I've said, I agree with you on the most, but the question that still hangs on my mind is, how does it know how much fresh air its getting? It is purely down to the amount of air that travels across the sensor? There is no sensor after the combustion point to tell it the outcome of O2, unburnt fuel?

If that is so, if the MAF was to be almost shrowded/sleeved slighty, this would hide the extra air flow because of the partial data it receives?

This would makes sense in some way, as i have read a few owners "twist" the MAF sensor in its housing, so instead of allow air to flow over it freely, the sensor creates a turbulence by being raised against the incoming air, thus doesnt feel the same air flow? Bit like basic air plane wing physics, more air flow on the base edge than the top edge, giving upthrust because of the air flow/turbulence difference.

Going to be very intrested in this little experiment.. will close a few questions and open others.

 

[cheshire cat]

TDI's do have O2 sensors I believe.

The EGR valve opens to the exhaust system and the "throttle plate" (as some call it) closes and creates a vacuum which then top up by the increased flow of exhaust gases. The O2 sensor is the feedback to the ECU which controls this.

only on non turbo--- where is the O/2 sensor?

 

[jabbasport]

You're on the right lines now with the MAF sensor.

It bases injection on how much air it sees coming through the sensor. That's why it's important to have a fully funtioning maf sensor. Also why, when people get boost leaks the mixture becomes smoky (rich) because the air the turbo draws in through the MAF sensor isn't wholey being forced into the engine, like i say, making the air fuel ratio rich.

 

[slick]

You're on the right lines now with the MAF sensor.

It bases injection on how much air it sees coming through the sensor. That's why it's important to have a fully funtioning maf sensor. Also why, when people get boost leaks the mixture becomes smoky (rich) because the air the turbo draws in through the MAF sensor isn't wholey being forced into the engine, like i say, making the air fuel ratio rich.

So when the EGR valve opens, the ECU looks to the MAF for lower readings.
If so, then if you some how blocked the MAF sensor from recieving all the air flow, and matched it to the reading it requests with the EGR valve fully open, it wouldnt throw up a fault code.
As when full throttle is introduced, as long as the final reading is still over the requested you shouldnt see a drop in power due to a lower fuel injection?

 

[jabbasport]

Kind of, but then if the maf sensor doesnt recieve all of the air flow getting into the engine it wont be injecting the correct ammount of fuel, and airflow/boost references wont be right either and you'll probably get a fault code anyway, just for a different problem.

Lets just say, the MAF NEEDS to see exactlly how much air is flowing into the engine at all times to produce an efficient burn. That's why people's economy drops if the air flow isn't reading correctly.

You shouldnt start to try and fool sensors to clear fault codes, they should be mapped out properly.

 

[slick]

You shouldnt start to try and fool sensors to clear fault codes, they should be mapped out properly.

Well that excately what i dont understand.... not many tuners no how or want to tune it out?

Only a hand full of tuners i know off that actually custom map to each different car, i guess it a cost thing?

 

[jabbasport]

Well that excately what i dont understand.... not many tuners no how or want to tune it out?

Only a hand full of tuners i know off that actually custom map to each different car, i guess it a cost thing?

That's of course where research and development plays a big part in mapping vehicles.

We used to only custom map vehicles, but with more and more tuners offering a cheap Stage 1 option we now offer Generic and Custom options but prefer to custom map.

I dont suppose you're local to us? I'd be more than happy to perform the adjustment within your software to remove the fault from your ECU. That's of course if you have this problem.

I'm off home now

 

[slick]

Well I'm not local but I will be looking at getting a custom map to my car in the near future to take in all the modifictions i have, including the EGR removal.
I'm guessing when you say remove the fault you mean permantely map out the EGR and not just clear the fault code?