E.G.R. Disconnect.
 

there was some discussion some time back about minor mods to make engine perform better. one of these was the disconnection of the egr valve. my engine has been performing poorly for a long time and my attempts to get the dealers to fix the damn thing or even admit it was suffering from poor performance was the cause of all my problems and arguments with them as most of you on the forum are aware. the problem got so bad i finally decided i had to something myself. last week i removed the egr valve vacuum line from the egr valve and plugged it. went for a short drive and it seems marginally better. went for another drive and it was better again. now having covered about 200klms just round town the engine has a totally new lease of life. the thing pulls like a mack truck at any revs and will in fact take of from a standing start IN FOURTH GEAR!!!!! it's pretty obvious the egr can totally stuff these engines if there is any problem with the egr system, and that the installation of an egr system on the engine seriously impares it's ability to function. the engine starts normally and runs normally and shows no sign of any heat buildup on the temp guage, nor does it warm ap any quicker as you would expect if the engine ran hotter. the only ting i have noticed is a bit more engine rattle on the first cold start in the morning, due to the fact that removing the egr gas from air charge to the engine means the injector timing is a bit advanced. but the rattle subsides as the engine warms and disappears totally. the result is a beautiful engine, which is totally flexible and performs strongly at almost any revs and can even take off from rest in 4th gear. i can thoroughly recommend the mod to anyone. fuel economy should also improve as there is now a complete fuel burn in the combustion chamber. will let you know how that goes after a decent trial over a few thousand kms. cheers.

Works well for most Davidd, would be a good idea to install a exhaust temp sensor, (VVT) Variable vane turbo's on some diesels dont take kindly to the removal of their auxilary cooling system being inert gas from the EGR.

My EGR valve is stuffed (noisey), can hear it cycling flat out after heavy use due to higher exhaust temps.

The EGR on a diesel does not have the same effect on the exhaust pollution as a petrol engine, it has no benifit in regards to pollution other than cooling the turbo.

If you work your rig hard i advise a exhaust temp sensor to ensure you dont detonate the turbo/engine. :)

Not trying to upset anyone but if there is no pollution benefit from EGR, why is it being fitted to heavy diesels to help them meet emission targets. I was under the impression that by using exhaust gas in the charge air was to give a more complete burn. There is also a lot of discussion within the truck industry about the increased cooling demands of EGR engines.

I am happy to be corrected if this is wrong

Exhaust Gas in Inert meaning it gives no flamable benifit, does not assist with burn, just fills the combustion chamber with inert Gas which doesn't burn, lowering exhaust temps.

Secondary Injection assists with with removing any hydrocarbons which are not burnt in the combustion and make it through to the exhaust, introducing oxygen enriched air to the exhaust deals with this _ This is a cold start function to deal with enrichment of mixture in petrols.

EGR pollution control gives maybe 10% benifit to pollution control where as the Petrol EGR will have 100% for eg. It's NOx which the EGR is designed to deal with, Which is an issue with high Exhaust temperatures introduced with running a leaner mixture (petrols)

It was orginally fitted for pollution control but later to find that it did not have the same outcome as with a petrol engine, however could be used to cool the Variable vane turbos.
Cools the turbo but heats up the cylinder head.. this is the cooling issue you refer to, and is an issue as seen with older Generation turbo diesels removing the EGR system decreased temperatures.

It's a fine line with diesel EGR, run without it you see the higher exhaust temps, run with it you run higher engine temps. Going to be more of an issue with the next generation of diesels just around the corner.

Can certainly see how they imposs issues with larger earth moving equipment.

MCJK, thanks for that. i was told that egr was to cool the temp. in the combustion chamber to prevent the formation of NOx. it seems you're saying that in fact the egr raises the temp of the combustion chamber and cools the exhaust gases. i'm a bit lost here. if you put an inert gas into the combustion chamber i thought you would get an incomplete slow and cooler burn. introducing pure air with no egr would give a quicker hotter burn with consequently hotter exhaust gas. this obviously not right. can you give me a quick lesson here to bring me up to speed?

as an aside here, with regard to pollution control. have a mate who is in contact with a group of fanatics in the states. they have done quite a few mods including software mods to the ecu. they have found that running without the egr connected has had no ill effects over extended distances and no effect on pollution emmission. have been pulled up in the states by police and had pollution checks (apparently quite common there) and have passed on all occasions with flying colours, so it is not an issue if these checks are used here in the future.

MCJK is the injector timing an issue as it only seems to be there on a cold start. also does the jk have an anti-knock sensor to alert a problem or control excessive timing advance and retard injector timing to stop damage? you have been runing without egr for some time and don't mention any adverse effects from advanced injector timing. this seems to be in line with what the bloke in the states are experiencing.

The KJ and Wrangler CRD guys in the states with the diesel {VM2.8} have developed a bypass electronic module that disables the EGR valve. As others have pointed out EGR has limited benefit in a diesel, and is almost exclusively used at idle or crawling in traffic. At any point where real boost is provided by the turbo (1800rpm plus) the EGR is normally closed. You need to watch out concerning plugging the vacuum line to the EGR valve as I believe the late model JK CRDs use the electronic control of EGR.

ECU flashes by GDE in the States also disable EGR (just doesn't actuate the valve opening) and provides significant performance improvements. I believe Inmotion also offers a similiar reflash of the ECU. Unfortunately for us it means you need to remove your ECU and ship it to them for the reflash. It would be nice to have a sort of USB key for this type of change. Obviously, Jeep might reflash you back to stock if they detect a problem during normal service cycle but so far the US guys say they don't even know its there. Here's the GDE website:
http://www.greendieselengineering.co...do?method=home

Don't forget that they don't have Wrangler CRDs in the US so GDE focuses on the KJ CRD, but it is still interesting reading.

Keep us posted with this mod, is it easy to do, and what fuel consumption benefits are you getting?

Thanks for the explanation MCJK. Appreciate the info.

yep, blokes in the states have produced what they call an S.E.G.R. which is a bit of circuitry they put in the inlet airflow sensor and disables the egr valve. apparently in the kj the MAF sensor pretty much just operates the egr system and not much else. mine used to work just as you say, but over time, after i first found a problem acceleration got worse and worse, and eventually the only time i got any acceleration at all was at startup or if i had been idling at traffic lights for 3 minutes. seems to me the egr valve just opened and stayed open filling the engine with soot and preventing the kind of burn needed for acceleration. i also noticed shortly after the problem started that my battery had been disturbed and there were spanner marks on the ecu. so possibly an ecu problem has developed by some means. but disconnecting the egr gives me back low rev performance again and more pulling power. jk's have electronic control of the vacuum to the egr valve, but i haven't seen any yet with full electronic control. they have an electronic actuator sitting on top of the egr valve, as do the rodeos, isuzus and some others. the jk has a solenoid control valve on the rocker cover that controls vacuum and hence operation of the valve. tried disconnecting solenoid and another couple of things and they all threw check light on dash board. plugging at the valve end of the vacuum line was the only thing that worked and didn't disturb the engine management system. another thing that could cause all the excessive egr flow and lack of accelleration is a faulty airflow valve in the throttle body. getting a dealer to admit that and replace it would be like p***ing upwind too. so i'll just go with the plugged egr valve. have also thought of removing the air flow valve as well, as without the egr valve it isn't needed anymore. but will look at that later.

it's easy to do. just pull the vacuum line off the egr valve control on the back of the inlet manifold, and block the line with a ball bearing, rivet head or anything you can find to stick in the rubber tube. that's it. and it's instantly reversible if you want to put it back to stock, just pull out the blocker in the tube and stick it back on the egr valve again. fuel economy i don't know yet. will take me awhile to check that as i have a long range tank which makes it impssible to accurately measure how much fuel goes in the main and how much in the subtank. dash readout sticks a bit too. reports from the states are about 10 percent. MCJK has had his off for quite a while he may have an idea if he gets back to this thread

Combustion Temp is lowered, it's just the fact that Exhaust gas is hot and is being plumbed in through the instake heating up the Intake side of the head is all.

Issue with only removing the EGR Valve from the system is the throttle body is still attempting to actuate, for eg. if the EGR valve opens 20% the throttle body must close 20% to compensate for the introduction of the EGR gas.

Strangly enough the ECU is not detecting this issue, it is monitored via airflow meter - O2 sensor, what comes in must come out.

Idle seems to be increased once engine has reached operating temperature with EGR disconnected.

Software would be ideal to eliminate the EGR system.

Fuel injection timing shouldn't be a real issue, as stated previously by others it's only active at idle or during decel. If the mixture formation is altered in these diesels it is noticable, they will rattle like an older generation diesel.

Would be interesting to see what exhaust temps were like with a performance chip installed with EGR eliminated, thats where it gets interesting.

Dav, also on that note my engine does not rattle on cold start or hot with the EGR connected or disconnected.

These motors really dont need more power, just an improved torque curve which is achievable via the after market ECU upgrades. sufficient power at 1800rpm to break alot of things as it is lol

What exhaust temperature would be dangerous for the turbo? I have used exhaust temp gauges in machines but they are usually colour banded.

mcjk. i get rattle at idle when engine cold (with egr disconnected) can you give me a clue there as to why? also are you saying that without the egr valve operating the maf sensor helps compensate for the lack of gas flow or is it simply compensated for by the map sensor calling for a bit more boost and getting the airflow valve opened a bit more? if you block the egr and the airflow valve doesn't open more you choke the engine and lose power, not increase it as is happening. also my engine idle revs don't change, still steady at 800. but much stronger at idle. if the air flow valve is an issue with the egr blocked, is that problem solved by removing the airflow valve or are there other issues as well?

ECU is the chief, it must be tricked by the fact the EGR is inoperative and doesn't actuate the throttle body at all or it would be more noticable.

MAF sensor is only a messanger, ECU decides what to do with this message in relation to it's point in the mapping. the EGR is activated (although inoperative due to being blocked), no change is found as per the O2 sensor data in relaxing to MAP data, so ECU must not actuate the throttle body to compensate, the end result is the ECU ensures Smooth running in regards to mixture formation <- this is the only logical explanation.

As for noisey cold start, if it's a tappet bleed up type rattle, it's either a full set of cam followers (unlikely) or incorrect oil.

could the rattle at cold startup be advanced injector timimg, caused by removing the egr gas ?

So MCJK your saying no need to remove Air Flow Valve as ECU will pick up via O2 sensor that EGR valve hasnt opened, if thats the case i'd expect the 'Check Engine ' Light to come on? Wouldnt do any harm removing the Airflow Valve as i know others have done it.
Do you know the Max Exhaust temp at Turbine for the 2.8lt VM Motor?
Im looking at a Cummins spec chart now and states 430Deg C for Turbine out temp & 592Deg C at Manifold but doesnt list a Max Temp. I do know of another that listed 650Deg C Max temp.
Do you know? Are you a Motor Mech?

Best get a quote on a new VVT turbo guys, if it goes pop.. not cheap..
either is the engine.

Ive found diddly squat advantages of disconnecting it, i only disconnected mine as it was busted and noisy, fuel is the same, power barely noticable if anything. Software is what is needed to properly rectify the EGR to gain the full benifit of the modification. remove it completely.

Davidd's EGR must have been stuck open, this explains the massive difference he has achieved from disconnecting it.

Best way to save Alot of fuel is free wheeling hubs, pulling the front axle due to breakage on trail has dropped my fuel by over 4L per hundred city traffic. (will be back to normal once axles sorted)

Davidd, shouldn't rattle at all, must be another issue. there is a knock sensor, but being a diesel the knock threshold is very high

No Engine light, Engine mixture formation must being running within specific values, EGR only works at idle or decel, the variables of the specific values from sensors are Wide. Looks like it sucks it up.

Personally i do not have a spec sheet nor know the specified temp for the 2.8L VM, but in saying that a Garrett turbo is a Garrett Turbo regardless of what it's bolted to, over 750 degrees longivity will be an issue, if you can boost it up at a max 650 degrees with a nice power gain, which there would be, go for it.

I know ppl run higher temps, but this is a daily driver here, if your manual you can kiss your clutch/gearbox good bye if there is a huge gain in power lol

interesting what you said about the hot egr gas raising the combustion temperature in the cahember. the u.s. blokes are saying they are running cooler with the egr blocked. their story is cooler engine, no pollution, more power and better fuel consumption. mate of mine has a kj and he gets knock at idle when cold, just as i do, when the egr is disconnected.

EGR is specifically designed to lower combustion temp to lower NOx, by product of this is the cooling of the turbo, Intake side of cylinder head/intake manifold temperature is increased do to the heat soak from the EGR cooler.

The O2 concentration is reduced in the combustion chamber, Reduced exhaust flow (power loss) and reduction of the combustion chamber temperature as a result of the improved heat collection capacity of the components e.g. water and CO2 which are not actually involved in the combustion but do influence the combustion process.

EGR is active in the lower load and rpm range. the EGR rate depends on engine load and engine speed, it's not all about MAP signal input, there are atleast 9 other inputs in which the ECU uses to calculate EGR activation.

No knock present in my engine, may wish to consider the type of oil your using? im running mobil 1 ESP, although i have no DPF this oil is better suited to a diesel.

thanks mcjk. have only had this egr valve off for a few days about 300klm. truck seems to be improving every time i get in it. i think you are right about the valve being stuck open. there was zero acceleration, no performance at all (totally gutless) under 1800rpm. would still wind out to higher speeds but took a long time. now pulls like a truck from very low revs, anything over 1200 seems enough to get response in intermediate gears and anything over 1500 is plenty in top gear. gets better all the time. i think this thing was just plain clogged up to blazes with soot as well as suffering from excess egr gas. what you say about load makes sense, i have been running round town on short runs and lots of traffic lights for 6 months, empty vehicle. ideal for clogging up. am using hpr diesel 5 oil. is not low ash, but has better dispersant and detergent properties than low ash if you don't have a dpf. have tried alternating with low ash. low ash gives clean oil at oil change. a following hpr diesel 5 run, flushes out a real pile of muck. another run of diesel 5 gives relatively clean oil. has been my experience that low ash definitely deposits more sludge in the engine. but the diesel 5 is a 5w grade on the bottom end so should be fine. engine is still cleaning out after the egr problem, but have much stronger engine showing excellent low to midrange torque, slight power improvement on top end (still down a bit), and so far no noticeable difference in fuel economy. however it takes a much lighter pressure on the gas pedal to get a result so something is going right. have also noticed that if i put the foot down at 100kph it is starting to give a bit of a kick again, instead of just dragging itself up. this thing must have been absolutely chockers with carbon. it is still getting better every day.

More of an issue i have found is the transmission, seems to me it's mapped for a petrol and not a diesel, the Superchip and a few others deal with this issue, the auto kicks down when it should infact hold the gear.

it's acting apon the modulating pressure (engine load) to soon, the Engine has enough UMF to pull the tits off a bull, why kick down and push the revs up above 3000 rpm when it's not required. the 5 speed is good, just needs a tweak i reakon.

You will find with higher end diesel vehicles on the market, their autos hold the gear longer, makes for a different vehicle all together.

mine is a manual 6 speed, so don't have issues there. it seems most of the blokes with auto issues have added a transmission cooler and the problem goes away. box holds gears longer and fuel economy improves. you may already be aware of that though. steve (redgp) had engine heating problems and transmission problems. added an outo trans cooler and everything fell into place. engine temp dropped and auto trans started working right again. mate with a kj diesel had the same problem as you, and was talking about all kind of mods including changing to a more agressive torque converter. bought the converter (ex u.s.) and then tried a trans. oil cooler and the problem went away. engine cooler, auto trans cooler, and gear changes better, and held gears at lower revs without changing down. just an oil temp problem apparently. the torque converter still sits on the shelf in is workshop.

davidd, i was always surprised to hear you running your engine at ~2400. thought something wasn't right there. after my engine bedded in, i rev it unladen at these rpms:

1600-1800 in 3rd through 6th gear cruise on flat,
2000-2100 gear up shift on falt,
2000 in 2nd through 5th gear go uphill (8-10% gradient),
max 2400 gear up shift uphill.

when revving it ~2500 the engine sounds big and hard. in go-stop-go city mode, fuel consumption ~10.6ltr. tried, for experement, to run it at 2000 in city, fuel consumption up to 12.5ltr. interstingly, the engine sounds so happy when 1600 in 4th (60kph), 1700 in 5th (80kph) and 1800 in 6th (100kph).

That is exactly what I do EugeJK. My truck is quick happy chugging along at 1400-1600rpm on a flat road. I haven't seen a hill yet that it won't eat up at 2000rpm, regardless of the gear.

Mine is is the same. Even when overtaking it pulls from 1200rpm in 6th gear.

Interesting that these low revs are when the EGR is operating most.

I wonder at what rpms EGR shuts down to 0%? I can smell it from exhaust **) at idle when tacho shows 850 rpms. Give mine a bit over 1200 and there're mild pleasant diesel fumes :rolleyes::

yep, mine was the same when i first bought it. went up hill in 6th at 2000 with a camper on the back and the rear of truck full of gear. got worse over time till it had no bottom end performance at all and had to be run over 2000rpm to do anything. numerous trips to dealer (dvg maddington and melville) got not even an admission there was a problem in . spite of me producing torque and power charts to the dealer. was told the engine was normal and that i would have to rev it out near the redline to get any performance out of this tiny 4 cylinder. it was the reason my vehicle was trashed at dvg maddington, when the workshop staff threw a hissy fit to teach me i should go away. i was told there was nothing wrong with it but they had "given it a special heavy test just for me to show there was nothing wrong". that was the cause of my endless bitching posts on ajor and the 18 months of arguments with DVG where more more faults kept appearing each time i went back. and approaches to chrysler were a waste of time. they simply referred me back to dvg. but that's history and i'm finished with that. so it all stemmed from a faulty egr valve. blocked off it runs great and still improves every day. obviously much muck in the system to be cleaned out. if it works o.k disconnected i will leave it. i have been told by diesel experts that there should be no ill effects from it and in fact most diesels wind up up with a blocked egr sytem over time it isn't even noticed. if it looks like there may be problems i'll pull the valve and actuator, clean around the valve orifice to stop it sticking and replace the valve. a messy fiddly job, but not hard. it is just amazing to me that in order to avoid doing a warranty job, a dealer will damage a customer's vehicle to try and get rid of him, and chrysler does nothing to intervene on the customer's behalf. in fact i was told that if i have issues with the dealer they "will do everything they can to not get involved". amazing. but anyway that's my final rant on this, i want to get on wirh my life now. i have found the problem and have a quick fix, possibly permanent. my vehicle runs again and is an absolute joy to drive again. a hugely gutsy torquey engine that pulls like a train and does what it is supposed to do. like you mine now plugs along quite happily at 60kph in sixth, and now the bottom end is restored it accelerates uphill reasonably well from 70kph in 6th. life is getting good again.:)

euge, i don't know the answer to that, but it seems that from reports on the kj in the u.s. chrysler have ramped up egr to rediculous levels, so i guess it's the same here, and the jk is probably the same. with early diesel egr systems, the gas only entered the cylinders at idle or under deceleration. with the latest diesels the gas also is injected if the engine is running under very light load conditions or if running at very low revs (revs not specified). so unless you are towing or have a load on board or are running at highway speeds it seems there is a good chance you will have some egr gas running through the engine. a permanent injection of soot into the engine to clog up inlet manifold and cylinders and injectors and valves. would seem it would be a good recipe for a short life engine. but i'm not an expert. a diesel bloke i was talking to did comment on the wrangler by saying "the bloody egr is rediculous, i don't know why they haven't at least wound it back if they can't disconnect it". it seemed an experienced bloke who had had experience working on them (outside chrysler) seemed to think the jk egr gas injection was excessive. and inspite of all the warnings about anti-pollution laws and excess heat produced doing damage, those in the industry outside the dealerships seem to say the egr does little or nothing to reduce pollution and the bit of extra heat produced is not damaging to the engine. time will tell i guess, but if anyone can come up with any more information i would be pleased to hear, because it now of great importance to me and of interest to a few others who have joined onto this thread.

euge had a look at your figures you posted. mine revs higher because i have the 4.1 diffs. at 100kph in 6th i am doing 2400 rpm.

Im a little spoilt for choice, im comparing the Auto against Merc v6 diesel mated to a 7 speed box Auto and other Euro combinations, they are pros when it comes to this aspect of engineering, The Japs and yanks cant seem to fine tune the engine+trans to same level (even in the petrols). Even the little merc 4 cyl diesel and old 5 speed auto box is a perfect match (pretty much produces the same power as the VM 2.8)
It's not a trans cooling issue if the box shifts down if it's not overly hot is it? Redgp is also runing a superchip which sorted his trans changes.

The new generation of small 4cyl diesels will be producing as much power and torque as the current generation of V6 diesels, poor little spark ignition lawnmower motors are being left behind :p

hi mccjk. all i know about the gear change thing is that it seemed that it went away after the cooler was fitted. engine temp also dropped, and it held gears at lower revs afterwards. what gearbox temp was before cooler i don't know, but it seemed the cooler sorted it. and yep, these small diesels are pumping out some serious horses and torque with the 2.8 at 460nm now off the production line, so you can bet they are working well within their limits at that. probably can put out over 50nm safely i'd say. incredible stuff!!!! this was V8 territory not so long ago.

sorry over 500nm i meant

davidd, who is servicing your vehicle? It sounds like you may have an inadequate oil being used in your vehicle.

yom, are you referring to the auto trans oil? that's not me that's redgp and a mate who had auto trans issues which were solved by fitting a transmission oil cooler. if it's my engine you are talking about. i started using dealer 5w30 low ash, switched later to penrite hpr0, a 0/40 low ash oil. then as the truck doesn't have a particulate filter and taking advice from the penrite technical rep. i changed to penrite hpr diesel 5 a 5w40 synthetic reinforced oil, (semi-synthetic). found to worked fine and cleaned lots of carbon deposits from the engine due it's higher detergent and dispersant properties , compared to the low ash oils. i have a rattle at first start on a cold morning which goes away as the engine warms, but have been advised that is due to blocking the egr, which gives a quicker burn and has the same effect as advancing the injector timing. can be corrected if necessary apparently. all good oils and serviced by reputable people, a place i have gone to on and off for 20 years, good honest decent people. totally reliable.

the rattle at cold start is gone within 2kms even on these mornings at 5 deg. the temp gauge has hardly even moved in that time.

HPR DIESEL 5
Advanced formula synthetic performance engine oil for superior protection for modern high performance diesel engines including turbocharged. Ideal where SAE 5W-30 or 10W-30 is recommended. Primarily for 3.0L diesel engines and diesel engines with hydraulically controlled fuel injectors. Vehicles with DPFs must use Enviro+ or Diesel SP.
SAE 5W-40, API CI-4/SL, ACEA A3/B4, MB 229.5, VW 506.00/506.01, Global DLD-2/3

HPR DIESEL
High viscosity formulation offering greater protection for older diesel engines. Ideal for extreme climates, high loads or oil consumption problems with conventional viscosity grades. Suitable for turbocharged engines too.
SAE 20W-60, API CH-4/SJ, ACEA A3/B3, M2C 911-A1, Global DLD-1

http://www.penriteoil.com.au/product...hpr/hpr_diesel

Has anyone been in contact with VM to see what their recommended oil specs for the 2.8 are? Nissan and toyota are more than willing to specify what the minimum requirements are and I doubt Chrysler AU would know so may as well go straight to the source?