E.G.R. Disconnect.

[davidd]

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.

[MCJK]

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.

[BigfootBushy]

Originally Posted by MCJK

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

[MCJK]

Originally Posted by BigfootBushy

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.

[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. 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?

[davidd]

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.

[davidd]

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.