Deisel EGR Valve's ?

[David-Butter]

My son has just purchased an EGR Valve Block off pipe for his Golf 5 TDI. Im lead to belive this recycles exhaust gas for a cleaner burn and less smoke so blocking it off = more power How ?

Could some one shed some light on this for me

 

[turbopete]

not sure it gives more power, unless the egr valve is faulty. common cure for problem egr's is to blank them off.

 

[David-Butter]

i had found the power and respoce talk on the vw forum. Its said that due to no hot exhaust gas the is more power ? I somehow cant get my head around it he has now got it in bits in the garage so we will see soon (not got my hopes up)

 

[Miffy]

I think the theory is based upon a cleaner burn as your not pumping partially burned fuel/air back into the bores

 

[turbopete]

I think the theory is based upon a cleaner burn as your not pumping partially burned fuel/air back into the bores

and also due to cooler air being more dense than warm air, increasing volumetric efficiency. in reality, ive blocked a couple off myself. driven the car before and after, and not been able to tell the difference. i think its more of a placebo thing, unless the car is remapped (very common with vw derv's)

 

[djb]

My son has just purchased an EGR Valve Block off pipe for his Golf 5 TDI. Im lead to belive this recycles exhaust gas for a cleaner burn and less smoke so blocking it off = more power How ?

Could some one shed some light on this for me

Egr valves are fitted to reduce the combustion temperature by lowering the oxygen content,with a view of lowering the Nox in the exhaust.

Obviously the manafacturer has to fit them to meet type approval to meet the required EU emmission standard.

Blanking off the egr in some instances with certain vehicles throw engine management faults as allowance is made for the re circulated gases in making fueling calculations.Dont knowif this applies to VW.

I believe blanking Peugots is quite sucessul though. Theory would suggest an improvement in MPG as well.

 

[Alex Crow]

blanking egr valve will not help bhp output. the egr valve is closed during turbo boost anyway, and so it is just the same as if it is blanked off. removing the valve body or blending body could potentially help due to reduced air flow restriction, but on a forced induction engine the gains would be miniscule.

 

[Razoo]

From one of my earlier posts:

"The EGR (Exhaust Gas Recirculation) system, recirculates exhaust gases (and all manner of crud) throught the engine via the inlet manifold.

The EGR system reduces combustion temperatures and NOx (Nitrogen oxide) emissions (and engine life, IMO).

Ford had a lot of trouble with the EGR systems on their early Duratec V6 engines (as fitted to the MkI Mondeo). The cats in the exhaust manifold downpipes were prone to breaking up. Small pieces of ceramic then entered the engine via the EGR system and scored the bores. Ford redesigned the cats and did a recall to replace the cat/exhaust manfold assemblies. I owned a Duratec V6 at the time and, rather than risk catastrophic engine failure, I fitted a homemade steel blanking plate between the EGR valve and the inlet manifold. The car ran a whole lot better after that modification, and the ECU never realised the EGR system had been disabled."

My V6 Mondeo MkI certainly ran better with the EGR valve blanked off, but it was smoother, rather than more powerful. Mostly it was comforting to know that I wasn't recirculating bits of cat and other exhaust-related crud through the engine

Read all about EGR here:

Exhaust_gas_recirculation

Of course, if a vehicle has a faulty EGR valve that isn't closing properly, then blanking it off will show an immediate improvement in running and performance.

Razoo

 

[Alex Crow]

mercedes had similar calamities with the early 112 engines, broken cats fatally damaging the engine internals.

yes, if the egr is sticking open it will cause all sorts of prolems, but on MB cdi engines the ecu will notice and trigger limp home anyway.

 

[Razoo]

...if the egr is sticking open it will cause all sorts of prolems, but on MB cdi engines the ecu will notice and trigger limp home anyway.

Would the ECU notice if the EGR valve was blanked off (i.e. does the ECU monitor flow through the EGR valve in some way)?

Razoo

 

[dieselman]

yes, if the egr is sticking open it will cause all sorts of prolems, but on MB cdi engines the ecu will notice and trigger limp home anyway.

Would the ECU notice if the EGR valve was blanked off (i.e. does the ECU monitor flow through the EGR valve in some way)?

Razoo

Yes it will unless you either program the ECU to ignore the lack of EGR input (a VAG.COM can do that, or just reduce the % anyway), or fool the ECU input so it still sees the reduced MAF input when the EGR valve should be open. That is what I did, it works a treat.

EGR does reduce power and economy in light load conditions due to reduction of free oxygen in the cylinder. That's why it can cause black smoke output.
My new (old) car hasn't got EGR and as a result is average 2 mpg better than the same car with EGR.

 

[Alex Crow]

on MB cdi1-2 engines, the maf value at idle is pretty much halved when the egr is open - the ecu looks for this. on cdi 3 onwards the egr is electrically controlled, and if jammed will trigger positioner implausible type faults. possibly chipping or re-flashing an MB ecu could program it to run without egr, but this is beyond my day to day stuff and i have not heard of it being done on an MB.

 

[bollidear]

EGR Blanking/removal/fooling

To resurrect this problem, I have an annoying "limp mode" (ooo....errr) that manifests itself as a Speedtronic error.

But I'm thinking thats just a bum steer and it really an EGR issue I have. The limp only ever happens at low revs...and much more frequently after having stuck in traffic or alot of city driving (ie: low boost, idle situations that draw me to the EGR).

I cleaned the whole sorryful mess yesterday and as I moved a bucketful of filth and grime, was really quite hopeful....but not for long.

So I need to spey my Merc and remove or block off the EGR, fool the MAF...etc etc etc.

Using the collective wisdom on the forum, what would be the best way forward on a 2002 E270CDi? I already have the re-map and elected not to have the EGR removal remap. I'd prefer to chop the whole unit, blank or disconnect it or whatever to get rid of the pesky limp.

 

[Alex Crow]

bollidear, do you have any EGR related fault codes?

 

[bollidear]

Strangely not. Nothing has ever been registered for the frequent Distronic Sensor Dirty and Speedtronic either.

Its just a gut feeling as I can usually predict by the drop off in performance before the limp occurs. With London trips, its just a matter of time and you when the time is as the response slows generally to throttle action.

The only faults were an old crank position sensor (I put a new one in with no effect) and lots of old battery and voltage issues before the battery charging mod. Its had a brand new turbo & MAF and all the pipes appear ok without whoosing etc.

 

[oigle]

Why not do the egr shunt anyway. Even if it doesn't fix your problem, it is a worthwhile modification. Good chance it will fix the limp mode too. Only costs pennies if you do it yourself.

 

[Alex Crow]

What do you mean by a Speedtronic error? Does it just fail to work, or do you get a Speedtronic error message on the dash? Does the cruise control work?

If you have engine 'limp home' there will be stored fault codes for it - no ifs no buts.

Have all the other systems been checked for errors? Especially ETC ESP ESM etc?

Have seen the cruise and Speedtronic fail on a manual w211 because the clutch pedal switch had failed, an easy fix that one...

 

[bollidear]

What do you mean by a Speedtronic error? Does it just fail to work, or do you get a Speedtronic error message on the dash? Does the cruise control work?

If you have engine 'limp home' there will be stored fault codes for it - no ifs no buts.

Have all the other systems been checked for errors? Especially ETC ESP ESM etc?

Have seen the cruise and Speedtronic fail on a manual w211 because the clutch pedal switch had failed, an easy fix that one...

Hi Alex,

The limp mode fault was not identified by MBS or DWL (Gravesend) - and Evolution gave the ECU a clean bill before remapping it.

In fairness both MBS and DWL both said they would need to investigate further - bit there was no "smoking gun" error code.

Other symptons that may/may not be relevant:

Never occurs within first hour or so of driving and only after extended queuing or slow traffic.

Limp aways clears on restart but Speedtronic error often remains - usually to go back to limp after a few miles.

Just before going into limp it feels like you just want to boot it and clear the system out - its that kind of feeling!

Cruise dies as soon as Distronic Clean Sensor or Speedtronic faults come up - along with limiter function.

After a period of slow driving - a puff of smoke can be observed if you "put the foot down".

can't help but feel that rather than lose the car for several days to a mechanic or who or may not get to the bottom of it - I'd like to try the EGR, if only that it seems to make sense and is cheap!

I had a look around in the forums but can't find the definitive guide. A US forum suggested the resistor/diode/blanking plate fix only worked on a vacuum operated EGR - so if anyone can point me to the fix for an electrically operated EGR on a 2002 E270CDi - I'd be appreciative !

 

[toby1]

Have you read the "Disabling EGR" thread? May or may not assist you.

 

[bollidear]

That's the thread I was looking for......time for a little light reading!

I can see the mod is model specific so hopefully I'll find something for my petulant beast.