E.G.R. Disconnect.

[glend]

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.

[double black offroad]

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

[BigfootBushy]

Thanks for the explanation MCJK. Appreciate the info.

[davidd]

Originally Posted by glend

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.

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.

[davidd]

Originally Posted by bigsuzi

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

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

[MCJK]

Originally Posted by davidd

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.

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

[BigfootBushy]

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