More on the EGR Bypass Valve....Modify or Leave alone

[Mike Noc]

Originally Posted by Roverron

It might seem possible to have designed the Synergy to have diagnostic & self calibrating ability whereby it measured the maf signal and then compared it with what it should be and then produced a correcting map. But in practice this would cause far more difficulties for owners than choosing one of the 3 options.
Ron

Ron you've lost me - surely the only way a Synergy could compare the MAF signal with what it should be is to have its own MAF? And if there was a difference in the two readings then which one would actually be correct?

If they weren't so expensive you could have 3 MAF's in total and then the ECU can go with the two nearest each other....

Mike

[Roverron]

Originally Posted by mikeseignot

Ron you've lost me - surely the only way a Synergy could compare the MAF signal with what it should be is to have its own MAF? And if there was a difference in the two readings then which one would actually be correct?

If they weren't so expensive you could have 3 MAF's in total and then the ECU can go with the two nearest each other....

Mike

It wouldn't need its own maf because if the car could be driven under controlled conditions readings could be compared with those from a known good maf obtained under the same conditions. (ie ones I recorded on my vehicle which I would have had to assume was typical, and which after 90k miles it was unlikley to be)
The pitfalls are obvious so its not practicable, apart from the aforementioned other variables and the pcv valve which I forgot to mention.

R

[ChestersDad]

Points well taken Ron.

I was thinking more in terms of a the 'flat playing field' analogy whereby one has a base set of figures to start with describing optimal conditions as a look up table for the 'box' to compare to and then auto compensate for. After all there can't be much info from one sensor.

However, it's not an issue for me - I was just wondering how I would get along with it - thinking about its implementation in my limo!

[Union Wheels]

I agree Harry. (Post 291)

In the first post of this thread (3-12-2007) "Jules" askes if the EGR valve in Rover 75 will damage the engine.
I have read the whole thread, a good read, and my conclusion is yes it may very well damage the engine. Here are my reasons.

When the EGR opens more soot is produced. This means more soot particles ingested into the inlet manifold leading to more soot being produced (cumulative action). The extra soot finds its way into the engine oil and contaminates it. This leads to greater engine wear, particularly if the oil service intervals are not reduced. (see article about heavy goods vehicle operators in the USA somewhere in this long thread there is a link)

Other questions in this thread ask whether or not to fit a bypass.
I would say yes go for it and my reasons are:-

More oxygen in the cylinders equals less soot, therefore better engine efficiency which equals more power for same amount of fuel used: Or to put it another way better MPG.

If the EGR valve is left in place this will eventually clog up not just the EGR but also the inlet manifold which would lead to a less efficient engine, reduced MPG and worse emmissions than if an EGR had never been fitted in the first place.

My guess is that as manufactures were told to produce engines with less NOX, they found that by tapping off some exhaust gasses and feeding it back into the inlet manifold achived this relatively easily. They probably knew this would cause problems as the cars aged but were only concerned for the first 3 years or 60,000 miles (the high milers, would mostly be motorway miles and not cause any sludge build up anyway). Any problem after the warranty period would be chargeable work and a Win-Win situation for the Dealers (stealers). We the users of cars several years old are not so lucky!

So in conclusion, I will be removing my EGR (already disabled) and fitting a bypass as soon as funds allow.

Cheers Pete.

[HarryM1BYT]

Originally Posted by Union Wheels

So in conclusion, I will be removing my EGR (already disabled) and fitting a bypass as soon as funds allow.

Cheers Pete.

I really would not bother with the bypass, so long as it is disabled and clean.

[spyder]

A very good summary. Agree with all of it, and that is why I did mine, but I left the housing in to make it look standard, and it does work as well as a by-pass tube, for no money at all.
Except I used too thin a blanking washer and caused a headache for myself, but with the open egr, it demonstarated how badly the car runs with it open. All fixed now though.

Craig

[Mike Noc]

Originally Posted by Union Wheels

I agree Harry.

When the EGR opens more soot is produced. This means more soot particles ingested into the inlet manifold leading to more soot being produced (cumulative action). The extra soot finds its way into the engine oil and contaminates it. This leads to greater engine wear, particularly if the oil service intervals are not reduced. (see artical about heavy goods vehicle operators in the USA somewhere in this long thread there is a link)

Other questions in this thread ask whether or not to fit a bypass.
I would say yes go for it and my reasons are:-

More oxygen in the cylinders equals less soot, therefore better engine efficiency which equals more power for same amount of fuel used: Or to put it another way better MPG.

If the EGR valve is left in place this will eventually clog up not just the EGR but also the inlet manifold which would lead to a less efficient engine, reduced MPG and worse emmissions than if an EGR had never been fitted in the first place.

My guess is that as manufactures were told to produce engines with less NOX, they found that by tapping off some exhaust gasses and feeding it back into the inlet manifold achived this relatively easily. They probably knew this would cause problems as the cars aged but were only concerned for the first 3 years or 60,000 miles (the high milers, would mosty be motorway miles and not cause any sludge build up anyway). Any problem after the warranty period would be chargeable work and a Win-Win situation for the Dealers (stealers). We the users of cars several years old are not so lucky!


Cheers Pete.

Pete this all sounds reasonable but my experience with leaving the EGR in place and working is that there is no increased wear, increased fuel consumption or any other problems.

My car has been serviced every 15k miles, EGR cleaned a total of 3 times from new and the only things changed in the engine to date are the cam sensor and water pump. Now over 10 years old and mileage is 299461.

Mike

[Union Wheels]

Hi Mike Noc,

It would be interesting for the rest of us to know the type of driving you do, motorway, heavy slow traffic, mixed etc.
My car had done almost 80,000 miles when I bought it earlier this year and the EGR valve was caked in black sludge about 5 mm thick and below this a hard layer baked on which I had to scrape off with a knife blade.
Your high milage (30,000 a year) suggests a lot of motorway/ dual carriageway use which may effect the way sludge builds up.
As you have owned the car from new and know all its history this may shed more light on the EGR sludge problem.

Cheers Pete.

[Mike Noc]

You're right Pete a lot more motorway driving than round town. I'm a mobile service engineer so have worked from down in Plymouth to up as far as Nairn.

That's why I like this car so much - just set the cruise and it is an effortless chewer of miles. Once went from Portsmouth with a stop in Birmingham up to Aberdeen in one day (and on one tank of fuel - just!).

So at a steady 70ish on light engine loads maybe the EGR isn't opening that much anyway? There has been a fair build up when I have cleaned it but can't say as I noticed any difference afterwards.

I've never changed the PCV valve or filter either - rinsed them in diesel every now and again and they've been fine so far. Having said that, although I have driven the car from new it was a company vehicle until I bought it with 118k on the clock so the main dealer may have changed them once, but I doubt it.

Mike

[Union Wheels]

Hi Mike, ( Post 310)

Your experience with the EGR probably reflects the long motorway runs at speed. Cars doing average milages say 10k a year may be doing more mixed journeys and hence a heavier build up of "crud". I think your results are therefore not typical.

On another point, you say in your last post that you went from home to Birmingham and then to Aberdeen on a tank full of diesel. According to google maps thats about 558 miles on 14 gallons, less than 40 mpg.
On mixed driving my car returns over 44 mpg and I would expect more if I was doing the type of motoring you do.

With the milage you cover each year it would be very interesting to see if your mpg would improve with a bypass fitted (and it may save you some cash in the long run).

Cheers Pete.