Disco fuel consumption and "egr removal"

[Pete7]

Originally Posted by Tim M

How bad is the door - repairable or replacement needed

Doesn't look good but might just leave it for now, busy with other projects at the moment

There is something wrong if your using that much fuel but its basic stuff to check levels including the auto box when its cold, clean filters including fuel etc and see if there are any leaks from Turbo to intercooler and back to the engine etc. Managed 25 mpg towing Old Spice down through France all be it carefully.

Pete

[Pete7]

Originally Posted by Nasher

Pete

As its a door, can you not take the trim panel off and push it out from the inside? Nasher

Think its creased and stretched the ali panel, full NCB and full comp insurance, but think we pay the first £250 of each claim.

Pete

[Mollers]

Originally Posted by Nasher

I meant playing with the fuel pump screw.

The EGR valve on my Shogun jammed up and cost a fortune to replace.
You can't blank it off on the 3.2 like you can on the old 2.8 or 2.5. Buggers up the ECU I'm told.

Nasher

We have a 3.2 LWB Shogun, it's high speed cornering is diabolicle compared to the X5. What size wheels do you have? We have 16", I'm thinking of going to 18's or even perhaps 20's to stop it rolling so badly.

[jwalker]

Originally Posted by Nasher

Does the re-routed Exhaust gas really go through the normal intercooler on the TDi?

No it doesn't. Cod's talking shit again. And, a third of a turn on that screw is a lot. Tim, if you find the screw doesn't have a tamper seal on it, I suppose it's possible someone has played around with the adjustment before you got the vehicle. Screwing it out limits the maximum fuel and vise versa. But after the air filter, check the insides of the air hoses to and from the turbo. I've seen them delaminate inside and partially block the air supply.

[Searider]

My 320,000 mile manual 300TDI managed 28 last time I worked it out.

Has been worked hard all its life - 200,000 of those miles have been towing!

[Nasher]

Originally Posted by Mollers

We have a 3.2 LWB Shogun, it's high speed cornering is diabolicle compared to the X5. What size wheels do you have? We have 16", I'm thinking of going to 18's or even perhaps 20's to stop it rolling so badly.

Mollers Hi.

Compared to an X5 I'm not surprised, I consider them two completly different vehicles built to do two different jobs.

I've never expected it to go round corners very well, but conversly I'd like to see an X5 dig itself and a 2tn boat on a trailer out of being up to all four axles in gravel on the beach.

Seriously, I don't want to enter a debate about whats a proper 4x4 etc, but out of interest does the X5 have low ratio, diff locks etc?


Nasher.

[codprawn]

Originally Posted by jwalker

No it doesn't. Cod's talking shit again. And, a third of a turn on that screw is a lot. Tim, if you find the screw doesn't have a tamper seal on it, I suppose it's possible someone has played around with the adjustment before you got the vehicle. Screwing it out limits the maximum fuel and vise versa. But after the air filter, check the insides of the air hoses to and from the turbo. I've seen them delaminate inside and partially block the air supply.

Could you explain a bit better then - politely would be nice............

Why do people bother blanking off the EGR valve??? I thought it was because crap got into the air intake etc as the photo shows.........

As to a 1/3 being a lot some people suggest up to 2 complete turns!!!

[Jono]

Originally Posted by codprawn

Could you explain a bit better then - politely would be nice............

Why do people bother blanking off the EGR valve??? I thought it was because crap got into the air intake etc as the photo shows.........

As to a 1/3 being a lot some people suggest up to 2 complete turns!!!

The "Crap in the Intake" could be for several reasons...faulty turbo seals, oil from the crankcase breather bypassing/overwhelming the separator... the route of the bled-off exhaust gas, I don't know.... does it get reintroduced at the manifold or before the compressor? I thought at the manifold, in which case it bypasses the cooler...but it's a while since I had a 300Tdi... so someone who has one take a look and let us know...

[Jono]

Originally Posted by Jono

...so someone who has one take a look and let us know...

A look at the (crappy) diagram in the manual suggests that the EGR takes gas from the exhaust side of the turbo and dumps it straight in to the inlet manifold...not through the inter-cooler..

[Tim M]

Originally Posted by codprawn

Could you explain a bit better then - politely would be nice............

Why do people bother blanking off the EGR valve??? I thought it was because crap got into the air intake etc as the photo shows.........

As to a 1/3 being a lot some people suggest up to 2 complete turns!!!

That photo is pretty much what I found when I took the hose off. There was loads of stickly black sludge unside.

[Jono]

Originally Posted by Tim M

That photo is pretty much what I found when I took the hose off. There was loads of stickly black sludge unside.

...Oil from the crankcase (most probably)..or turbo seals .....?

[jwalker]

Originally Posted by Jono

A look at the (crappy) diagram in the manual suggests that the EGR takes gas from the exhaust side of the turbo and dumps it straight in to the inlet manifold...not through the inter-cooler..

Correct, it 'Ts' into the top pipe from the intercooler to the plenum chamber at the inlet manifold.

Originally Posted by Tim M

That photo is pretty much what I found when I took the hose off. There was loads of stickly black sludge unside.

If you are talking about the intercooler, which we were, that's most likely intake debris and oil from the turbo seals.
However, Cod's photo is a picture of the intake to the plenum chamber at the inlet manifold and this is after the intercooler. So, either he is trying to cheat in this discussion or he doesn't know what or where the intercooler is.

Originally Posted by codprawn

As to a 1/3 being a lot some people suggest up to 2 complete turns!!!

Well some people might but some people speak all sorts of nonsense, don't they?

[Cookee]

I got 22mpg towing the race boat up to Coniston and back with a 400 hp 5.7 litre V8 Aussie Ute - I reckon you're all going about it the wrong way!

[Nasher]

Originally Posted by Cookee

I got 22mpg towing the race boat up to Coniston and back with a 400 hp 5.7 litre V8 Aussie Ute

Interesting.

You're not exactly well known for your light Right foot

Nasher

[Tim M]

I was referring to the pipe in Codders' photo - from the intercooler where the EGR pipe joins on.

[BogMonster]

Originally Posted by Tim M

Where is this screw? Sounds worthwhile.

Ask and LR4x4 shall provide

http://forums.lr4x4.com/index.php?showtopic=31

It is a re-quote of an old post on a now-defunct forum, pictures can be found via the link at the bottom of the thread.

Pretty sure there is stuff on there about EGR removal as well

[codprawn]

Originally Posted by jwalker

Correct, it 'Ts' into the top pipe from the intercooler to the plenum chamber at the inlet manifold.

If you are talking about the intercooler, which we were, that's most likely intake debris and oil from the turbo seals.
However, Cod's photo is a picture of the intake to the plenum chamber at the inlet manifold and this is after the intercooler. So, either he is trying to cheat in this discussion or he doesn't know what or where the intercooler is.

Well some people might but some people speak all sorts of nonsense, don't they?

In every one I have looked at the sludge also ends up in the intercooler - there's this thing called gravity that probably allows crap to drain back down....

So I still reckon people who accuse others of talking crap should try to get THEIR facts right BEFORE name calling!!!

[Jono]

Let's think this through.... If it’s “Sludge” then it must have an oil (or water....bear with me on that) based component, surely? The gas that goes into the intake manifold ....courtesy of the EGR .... after the inter-cooler… is exhaust gas which, by definition must have been through the combustion cycle..yes? Therefore the oil in this gas, if there is any will be carbonised (Coke) , will it not? Now this stuff will quite happily build up on the inside of whatever it hits..such as the inside of the manifold etc… trust me on this one…I know my Coke… it’s the bane of my existence… It isn’t “sludgy”.. for want of a more descriptive word.. unless it’s combined with liquid… you’ve seen the black sooty liquid that comes out of an exhaust on a cold start ..that’s coke and water… So if it’s…and it’s feckin’ tenacious stuff.. dislodged from the surface of the manifold and falls…Cod’s gravity theory… then it does so as crispy little particles…which, when the gas flow gets going again disappear into the combustion chamber and out the exhaust…
If you’re looking at “Sludge” you’ve got to be looking at oil.. or Coke’n liquid mix haven’t you? Oil from the crankcase…over pressurised by worn ring/bore clearance gets fed into the air intake before the Turbo somewhere.. I’m guessing the air cleaner housing…and this is pretty much the most likely source of your “Sludge”…if there are no other symptoms….the other likely area is turbo oil seals… but these tend to give other symptoms too……So Junk the EGR valve if you want…its place is only to “help with emissions”…yeah, right… but look elsewhere for your Sludge source….

…anyone want to poke holes in my explanation?…’cause I ain’t no Diesel expert…horrid smelly things……fire away!

[Mollers]

Not sure where the whole coke/sludge thing came from? As most of you well know the EGR returns some of the exhaust gases back into the engine in simple terms. In no way is this going to make the thing run more effeciently. The combustion process requires oxygen and shoving pre-burnt exhaust gases back in there isn't helpful. Also, the temperature of the inducted air on a diesel is crucial (hence intercoolers). Significant HP can be lost if the inducted air is too hot, I know this from engne room temperature problems on a yacht. So, shoving very hot exhaust gas back in is doubly unhelpful.

[Jono]

Originally Posted by Mollers

Not sure where the whole coke/sludge thing came from? ....

First post...

Originally Posted by Tim M

.... Anyway, I was reading around and I became aware of this EGR thingy which recycles the exhaust air and ends up clogging up your engine with gunk.........

Then Codder's posts..

Originally Posted by codprawn

.... it does stop crap getting into the intercooler though......

Originally Posted by codprawn

The intercoolers clog up with carbon and oil from the exhaust.

Google comes up with this…..from a Process Engineer who works in the Petro-Chem industry..Ie the other end of the food chain from me…

“Now we come to the purpose of exhaust gas recirculation in a diesel engine. The goal of exhaust gas recirculation is to reduce the amount of NOx produced. There are three ways to do this: first, reduce the concentration of nitrogen in the fuel-air mixture prior to combustion; second, reduce the concentration of oxygen in the fuel-air mixture; and third, reduce the temperature, since the NOx-producing reactions proceed more slowly at lower temperatures. Exhaust gas recirculation does two of these by taking some of the exhaust gas and mixing it into the engine inlet air.
First, exhaust gas recirculation reduces the concentration of oxygen in the fuel-air mixture. By replacing some of the oxygen-rich inlet air with relatively oxygen-poor exhaust gas, there is less oxygen available for the combustion reaction to proceed. Since the rate of a reaction is always dependent to some degree on the concentration of its reactants in the pre- reaction mix, the NOx-producing reactions proceed more slowly, which means that less NOx is formed.
In addition, since there is less oxygen available, the engine must be adjusted to inject less fuel before each power stroke. Since we are now burning less fuel, there is less heat available to heat the fluids taking place in the reaction. The combustion reaction therefore occurs at lower temperature. Since the temperature is lower, and since the rate of the NOx-forming reaction is lower at lower temperatures, less NOx is formed.”


So…Can we say “Ditch the EGR, turn up the wick (adjust/map the fuelling), look forward to power increase and feck’ the environment “ ?.
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.Still doesn’t sort yer choked inter-cooler out though…