Mitsubishi Delica Owners Club UK™

THE KICK INSIDE · Joined: 31 Jul 2005 Posts: 1592 Location: Staffordshire

on the paj site this seems to be recomended....

now when i think about it (it makes my head hurt!) the egr valve SHUTS under acceleration (i think!) if its working okay....

so logically when your just tooling about its open, so your breathing exhaust...which means less oxygen so a richer (in petrol terms) mixture....

blank it of and it changes (leaner mixture in petrol terms perhaps??)and i wonder if this leads to less torque, so more kick down = higher fuel consumption...

so has anyone adjusted the pump and what were the findings???

now of course if you have had the pump seals done perhaps the mixture is reset leading to the fabled 30mpg!
_________________
A Delica - ITS LIKE A SWEDISH BRICK...ONLY BIGGER!

Google · Sponsor

Pajeropah · Posted: Fri Mar 23, 2007 20:38 Post subject:

I average 25 mpg and have done over the last 3 years. I blanked the EGR valve not long after getting the beast so now you're making me wonder if my 'sluggishness' could be that the EGR valve is blanked.

Pajeropah · Posted: Fri Mar 23, 2007 20:40 Post subject:

Just to add to that, when I came to blank the EGR valve off I noticed that the vacuum pipe to the EGR valve was not connected. So possibly the pump could have already been adjusted. Unfortunately I have no way of knowing!! Sad

ricke · Posted: Sat Mar 24, 2007 0:16 Post subject:

When your piston drops for the induction stroke and rises for the compression stroke the injector releases the fuel into the bore in the form of a mushroom shaped spray in order to atomize. When the air already in the bore mixes with the fuel you get what is called Fuel Charge Turbulance (FCT).
The better the FCT the more power is produced when the mixture ignites as the flame produced speeds across the top of the piston like a politician sensing votes, producing less CO2 and HC's out of petrol cars, or black c**p with diesels, as the temperature is so high it is all burnt off but there is a down side.
In order to get optimal FCT manufacturers machine the heads of pistons and the heads themselves into wierd and wonderfull patterns to ensure that the air in the bore does'nt just sit there, stagnant, but rockets around like a mini tornado mixing with the fuel as the piston moves.
The Exhaust Gas Recirculation system was invented to deal with the downside to excellent FCT....NOX...
Nox is a gas that causes cancer and is very good at it, and is produced in efficient engines that burn off the CO2 etc by having excellent FCT, hence extremely hot engines, so the Nox content put out by vehicles had to be reduced....
The way to get round it was to lower the temperature in the bore as the piston comes up for compression, ignition, and the way to do it was to introduce a small percentage of already burnt exhaust gas which reduces the amount if ignitable air slowing the burning of the fuel/air mixture in the bore therefore reducing power and Nox but in turn raising the CO2/HC's put out by petrol cars and the black stuff by diesels.
So you stick the blanking plate on and there will be an increase in power.
The EGR valve is shut on idle.
If the injectors are spraying the fuel in the bore in a line instead of a mushroom shaped 'plume' then you get crap idle but when the engine acelerates it will run better. A down side to this is that the fuel will not mix with the air properly so therefore will not burn properly and your power will be down and so will the MPG.

And i used to train people about this stuff, no wonder i got depressed!!!

Ricke
_________________
Technology limited only by the imagination....

THE KICK INSIDE · Joined: 31 Jul 2005 Posts: 1592 Location: Staffordshire

Well they saya little knowledge isa dnagerous thing, that was quite a lot of knowledge but only a little of it stuck with me!

So are wa saying the piston design in a uk spec 4m40 is different to jap spec one (uk spec didn't have egr jap did)...and why does the injector spraya straight line rather than a mushroom if you blank the egr?

is the implication that no pump adjustment is neccesary...

weirdly the only pistons i have ever handled with much other than a flat face were from (a) methanol burning funny cars - those should be mounted as works of art! and (b) from a italian 350 where the valves opened into heart shaped cmbustion areaas insidethe piston tops (done to allow the engine to be lower!)

don't doubt fora moment what your saying but i still think i aint understanding it!
_________________
A Delica - ITS LIKE A SWEDISH BRICK...ONLY BIGGER!

ricke · Posted: Sat Mar 24, 2007 10:21 Post subject:

The fuel spraying in a straight line rather than a mushroom pattern means that your injector is clogged up. Regardless of country of origin or type of engine a good injector when releasing the fuel will spray it out in a mushroom shape so that a mist of fuel is produced mixing with the air in the bore A lot quicker. The better the mix the quicker the flame.

If the injector is spraying a line of fuel into the bore then the fuel will not mix with the air in the bore but slosh around on the piston head and therefore when the mixture is ignited it will not burn quickly so therefore you have less power....
The quicker the mixture burns the more power you have.....
The main cause of an injector 'squirting' rather than 'mushrooming' is laquer on the tip of the injector.
All the fuel we use has a high content of laquer in it and as the years go by and the miles are added to the engine the laquer in the fuel causes a buildup of laquer on the nozzle of the injector till parts of the tip become glogged up preventing it from 'mushrooming' the fuel and instead forcing it out of any available unblocked section of the tip......

Head hurting session coming on......

The injectors are cleaned using an ultrasonic bath which blasts the laquer off.. There is injector cleaner on the market which you add to the fuel but it wears off after around 400 - 600 miles unless you keep adding it. This stuff just removes the top layers of laquer from the nozzle but it again builds up quickly so you are back where you started.

Soap Box Out.....

As to piston design being different then no they are not. The japs had EGR years ago as their emmisions regulations are far stricter than ours. Some people think catalytic convertors are a 'new' thing but the americans have had them since the mid 70's. HD Tv is being hyped as the new thing to have and will enhance our viewing pleasure blah blah blah, but again this country is so far behind the rest of the world. The Japs started transmitting in HD in 1959......

Right soap box away......

The flat topped pistons usually have a slight dome on them to increase FCT, the ferrari engine, Buggatti uses a similar principle, uses the heart shaped area in the head to increase the FCT as the piston comes up and compresses the mixture into the the head the irregular shape causes the FCT to increase under the pressure. Some pistons have an inverted dome on the top with a 1/2" raised pip in the middle but these are for bigger engines as more fuel need to mix with the air....

Basic rule.......

EGR working less power, blank it off more power.....

If blanked off and you want to be sure then take the Deli to a diesel specialist and get them to check the diesel intake and they may well crank it down....

I am off for a cup of tea.....

Ricke
_________________
Technology limited only by the imagination....

axe · Posted: Sat Mar 24, 2007 11:17 Post subject:

hi ricke
now that is a lot of infomation! but i didn't read in there whether you think its a good idea or not to blank it off (my eyes may of glazed over at some point), have you done yours?
i don't think mine has been blanked off as i am first owner from import,
i don't seem to have clouds of black smoke behind me.
should i have mine blanked off & why?

not wanting to sound to stupid!......to late i spose. Embarassed

but you can simplify the answer if you like

cheers
_________________
Alex

L300

Lewis · Posted: Sat Mar 24, 2007 11:20 Post subject:

General rule seems to be that if it ain't broke, IE: not producing clouds of black smoke, don't blank it off!
_________________

Copyright is retained for all my photos. Please don't copy them without asking permission
Do not blindly go where the path may lead you. Go where there is no path and leave a trail that others may follow!
ルイス

billy bob

ricke · Posted: Sat Mar 24, 2007 12:42 Post subject:

I have very few rules in life people and the main one is to agree with Lewis.

If it works leave it alone....

On the other hand i like to play with this stuff anyway and in answer to the question, no i have not bothered to blank it off......

But i am looking at ways of improving the MPG as it is scaring me the way the fuel gauge is following Newtons law of gravity.......

So AXE i may well do it this year just to rule out any future problems and we don't test for the reason the EGR is fitted in MOT's so it really is a win situation against future problems involving the EGR system, crappy idle, crappy acceleration, bad starting when cold etc should it jam open, which i have always known them to do....

The problem is is that you cannot see what the valve is doing...

General rule with smoke out the exhaust....

White smoke and you are burning water, head gasket is a favorite....

Blue smoke and you are burning oil, piston rings or head again, pressure test usually determines which one....

Black smoke on diesel is the fuel not being burnt totally and could be down to laquered injectors or overfuelling or the EGR valve jammed open. If you have crappy idle but smooth engine run when driving then probably injectors, so dump Wynns injector cleaner in it and see if it clears. If your idle is okay check air filter is okay, if so get fuel pump checked.

White gunge in the oil, usually on the dipstick and mixed with oil as it is drained,is water in the oil and again is usually down to head gasket split between an oil way and cooling jacket. If the white gunge is just sitting in the oil top up cap then it is usually condensation and is okay...

If you have a particualarly dirty engine going for MOT then a trick is to remove the air filter if the Wins additive does not clear it up and you have no time to get injectors sorted, but the idle may need cranking up slightly to compensate for the extra air going into the engine.Not that anyone would do that.....

Once i have the ICE side sorted then i will be looking at the engine/economy side of it to see if i can do anything with it but we don't as owners have much to play with as the Deli is such a heavy vehicle and it needs something powerfull to get it going which is where most of the fuel is used, as well as the 80-90mph tootle down the motor way....

I am currently waiting for an answer from Mitsubishi for a 'timed' oil change. We currently change the oil on a mileage basis but a diesel is better off changed on an hourly rate like the tractors/tanks etc are.....

Since the engine in mine during a morning run will do 29 miles but will actually be running for nearly 1 1/2 hours due to traffic and lights, god does this city love traffic lights, especially red ones, and even when it ain't moving the additives are still being munched in the oil, so if i change the oil at 6,000 miles the engine could effectivley have been running for over 18,000 miles...

So far no answer....

If they don't reply then i will have a chat to Mercedes who are far more accomodating and find out how many hours they say the oil needs to be changed on a UNIMOG.....

Time for another cup of tea i think......

Ricke
_________________
Technology limited only by the imagination....

andyj · Joined: 08 Sep 2006 Posts: 2412 Location: up norf

great explanation ricke..that would explain my loss of MPG after the egr plate was fitted

my reasons for fitting it were better MPG+power like some people had said

got an increase in power..but shitty mpg..

ahh well you live and learn

Cavegod · Joined: 17 Feb 2006 Posts: 711 Location: Pilling

i fitted a blanking plate 1 month after i got the Deli, seemed fine until i removed it out of curiosity last month and i noticed more power and slightly better mpg.

Sweetpea · Joined: 13 Sep 2005 Posts: 252 Location: Faversham, Kent

This is interesting stuff. I've been wondering about all this...

It strikes me that the theory and practice don't always marry up. I need to read it all again but theory seems to suggest that blanking the EGR should make things no worse and possably better. But many people report the opposite. Hmmm. I'll read again when I'm awake.

I briefly plugged a vacuum guage into the pipe to the EGR valve. It's interesting to watch what it does. Nothing at all until the engine warms up a bit. A supprise was that it seems to be able to control the vacuum level. Which I take to mean that the valve is not open or closed but it can be a bit open... Press the throttle even a little and it slams closed but opens again quickly if you don't boot it. It's a really active little critter.

An interesting thought... If the ERG is leaking then it'll dump turbo boost down the exhaust. Since the amount of fuel injected is linked to the boost pressure then a leaking EGR means less boost, less fuel used, more MPG???

Am I right in thinking that the magical "fuel pump adjustment" just limits the maximum amount of fuel the pump can deliver?

James
_________________
Blue L400 called Piglet...

green1 · Posted: Mon Mar 26, 2007 0:49 Post subject:

everything I've read about the blanking plate says that if the EGR is working properly than the blanking plate is not needed, and may make things worse... the blanking plate is apparently only a good idea if the EGR is knackered already, and then it improves things....
_________________

Sweetpea · Joined: 13 Sep 2005 Posts: 252 Location: Faversham, Kent

okay. So I took the EGR valve off today, found it to be in good order and plugged it back in. I also connected the vacuum guage again to it to see what it does.

I'm convinced it was smoother when i first set off but the vacuum guage shows it wasn't doing anything. That's got to be a case of "I did something so it must be better". The EGR valve well and truely closed until about the time you hear the second clunk as the glow plugs turn off.

Once warmed up the only diferance so far is when booting it from a stand still. It felt as though it "missed a beat or two" while the valve closed.
Oh yes. I hate to contradict Ricke who obviously knows what he is talking about but the EGR is wide open at idle. Well mine is anyway. Mind you, if it's supposed to be closed at idle that would explain the slight lag when booting it at the lights. (XR3 drivers! Rolling Eyes

)

My best way of explaining when it's open or closed is that it does roughly the opposite of the turbo boost. The more you have your foot down the more closed it is.
Judging by the vacuum guage at a constant 40MPH it's almost full open, at a constant 60 it's only just open.

James
_________________
Blue L400 called Piglet...

THE KICK INSIDE · Joined: 31 Jul 2005 Posts: 1592 Location: Staffordshire

Well i know more than i did - and am more confused (not abnormal with me..)

I have blanked my egr due to getting large black clouds when 'ahm' booting it....

other than that it idles great, starts with no issues etc...

MPG is low 20's and it weiighs not much more than my superb which does 40's! (admitedly a bit of an aero difference!)

so i return to the question...dos the pump need reseting when a blanking plate is fitted...and has anyone had it done and what was the result...
_________________
A Delica - ITS LIKE A SWEDISH BRICK...ONLY BIGGER!

Sweetpea · Joined: 13 Sep 2005 Posts: 252 Location: Faversham, Kent

When I unhooked the EGR 18 months ago I didn't touch the fuel pump and have been getting 21 - 22MPG like you. I have a heavy foot though. 75 to 85 along the motorway so I'm not too upset with low 20s. Better than the petrol Fourtrak I had before.

In your first post you were sort of thinking in petrol terms. I'm not sure thats valid. I reckon... There is no throttle on a diesel so it's always hugely lean. Since there is no mixture to set I reckon the adjustment on the fuel pump only affects the maximum amount of fuel injected (the equivilent of taking your foot of the pedal a bit). I can't see how that would affect fuel consumption unless you always drove with your foot clamped to the floor. The only adjustment that might be of interest is the pump timing?

I'm as confused as you. I have concluded that people who get 30MPG probably have a lighter foot than me! Or need new batteries in the calculator? Although that doesn't help with those who say putting the EGR back improved MPG. That I really don't understand.

James

PS The Deli is over 2 tons. How heavy is the Skoda!?
_________________
Blue L400 called Piglet...

THE KICK INSIDE · Joined: 31 Jul 2005 Posts: 1592 Location: Staffordshire

SKODA 1700 KG...

Delica 1710 KG....

So there really isn't a lot in it!

admittedly the skoda has a 2.5 v6 TDI engine thats about 20 years younger in design terms and a six speed box....

then again the skoda also does 140 and 0-illegal a LOT quicker....
_________________
A Delica - ITS LIKE A SWEDISH BRICK...ONLY BIGGER!

Sweetpea · Joined: 13 Sep 2005 Posts: 252 Location: Faversham, Kent

Everything I've seen suggests the Deli is in the 2015kg area. At which 22MPG is kind of okay. But if it's only 1710 I'm worried.. It might blow away in the wind!

Where did you get 1710 from? Haven't actually weighed it have you?

A friend had a Skoda diesel. Very quick although my IS200 did a better job of the corners. And I can't get the idea of owning an Octavia RS out of my head... Just need more money and a bigger drive...
_________________
Blue L400 called Piglet...

THE KICK INSIDE · Joined: 31 Jul 2005 Posts: 1592 Location: Staffordshire

off the spec sticky on this site....

if its over 2000kg then i Can't get 5 ppl in at the max ladden is only about 450kg more than that....so a tank of juice and 5 big bods and your at max weight - any more and your illegal!

either way 300kg doesn't really explain the fuel economy, i was talking to someone with a big tatra today that would be equivelent and he reconed on about 30 !

i agree the big skodas suffer in the twistys, the wheelbase is too long, but then againthats why they have as much rear legroom as an S Class...also you haveto learn to trust the chasis it feels horrible if you take the power off, btu if your bottle holds out and once you get to learn to use tha active diff then they actually get better tha more commitment you give them...but god help you if you loose your nerve and back off mid bend!
_________________
A Delica - ITS LIKE A SWEDISH BRICK...ONLY BIGGER!