[Thecastle]

I recently purchased a second DDE had it cloned and tuned with stage 2 and EGR disabled. My car drivetrain wise is otherwise stock with all of her ABC's intact. I installed the new DDE and IA Know's EGR block kit. All seemed well except every other day or so I would receive an SES light triggered by code 4B82 or EGR flow implausible. I was like what the heck? Apparently the tune I have has the EGR disabled at all times except during DPF regen where it operates normally. The tuner changed their EGR code after a customer had a possibly related DPF failure, and felt the cause of the DPF failure was due to a fully disabled EGR.... Seems like thier taking a very conservative approach. I've seen folks at least with the stock programming run an EGR block for 50-60K miles and no DPF issues.

My goal with the tune was to improve my cars reliability and avoid CBU. Is it better just to remove the EGR block and let the EGR operate during regen's as the tunner suggests is best? Or just block it and not worry about it? Also wouldn't soot be at its worst during a regen in the EGR system with all the post injection events to force unburned fuel into the DPF to heat it up? Seems like a potential for a bit of soot. But then again since its off most of the time does it really matter? My plan as other componets fail is to tune them out, and to add a DP.m But for know I don't mind being stink and soot free.

What do you guys think? Kill the evil at its root? Or run with limited EGR?.....

[Torqu3]

Take off your EGR block and let the tune run as intended. These tuners have spent a lot of time figuring out what does and does not work, and what is best for the car. Best to let the tune do its job and not interfere.

[Thecastle]

Originally Posted by Torqu3

Take off your EGR block and let the tune run as intended. These tuners have spent a lot of time figuring out what does and does not work, and what is best for the car. Best to let the tune do its job and not interfere.

I would tend to agree.

However my goal is to minimize CBU to the point of irrelevance by disabling the
EGR. I had thought when I purchased the tune it was fully disabling the EGR, and adding the block would ensure no egr leaked through the valve. But it turns out that they offer two options, one that fully disables the EGR, and one that enables it right before a regen, as it seems to interfere with the cars ability to to do a regen. I can switch to the fully disabled version of the tune, but it might cause problems with DPF regen. I wish I knew more about how the DDE works.

[Hoooper]

Ask the tuner. Youre fine with a blocked EGR and stock regens, but that doesnt necessarily mean the tune hasnt changed something to make the EGR necessary during regen. My thought on that DPF failure is that the tune when turning off the EGR caused some other coding issue and theyre just being cautious not to make it happen again. The EGR is supposed to be closed during regen so a blocked off EGR shouldnt make a difference during that time.

[Thecastle]

Originally Posted by Hoooper

Ask the tuner. Youre fine with a blocked EGR and stock regens, but that doesnt necessarily mean the tune hasnt changed something to make the EGR necessary during regen. My thought on that DPF failure is that the tune when turning off the EGR caused some other coding issue and theyre just being cautious not to make it happen again. The EGR is supposed to be closed during regen so a blocked off EGR shouldnt make a difference during that time.

Good advice. I've contacted the tuner via e-mail.

They report in my tune the EGR is active during cold start to aid in engine warm up like stock, and during a DPF regen only. The rest of the time its closed. I suspect that this approach makes sure the engine will get up to full operating temperature so it can do a regen. So basically the tune is conservative in regards to protecting the DPF and running EGR when there is a drivability benefit. With the downside being you can still get a check engine light when the egr valve craps out or the cooler cracks, plus some soot still circulated into the intake. But this approach should giver a reduction in soot through the intake and an improvement in fuel economy, just like if the EGR was fully disabled.

I'm still trying to get an explanation of why this is superior to having EGR coded out entirely. Since they offer both options. I've probably answered my own question ....

[Dazza335iC]

Originally Posted by Torqu3

Take off your EGR block and let the tune run as intended. These tuners have spent a lot of time figuring out what does and does not work, and what is best for the car. Best to let the tune do its job and not interfere.

Seconded. If your EGR is only running during regens, that's still a 99% reduction over stock. I wouldn't worry even one bit about CBU at that rate.

[DreiD]

What tune?

[BB_cuda]

Off topic, I bet you're the guy that shipped me the failed HB from Ponder, TX. Thank you

[Thecastle]

Originally Posted by DreiD

What tune?

JR stage 2 tune with egr block.

I went with JR as when I was finally ready to tune bpc was having its little identity crisis and wasn't selling emissions disabled tunes. Plus JR is a little less expensive for the same tune as bpc.

I decided to go ahead and remove the egr block kit. Car runs great and I monitored the egr action. It only runs for about 4 mins on a cold start at 10-20% open then it's back to zero the rest of the time. Regens are happening as they should.

I also did notice quite an increase in fuel economy with this tune, probably mostly related to the egr being off.

[Nadir Point]

Originally Posted by Thecastle

I also did notice quite an increase in fuel economy with this tune, probably mostly related to the egr being off.

Any MPG increase is due to modified fuel and boost maps. EGR is useful for nothing but causing problems, and a small reduction in NOX emissions.

[remlemasi]

If the EGR is coded to be off 99% of the time, then isn't this effectively the same as installing a block at the intake only (i.e. nothing at the bottom on the engine block).

If so, doesn't this method make the EGR susceptible to cracking and coolant flowing back into the engine?

Just trying to understand all the factors at play here.

[Thecastle]

So that is a theory, that running egr closed without a block at the exhaust manifold will result in a cooler failure. one or two individuals about 3-4 years ago thought that their coolers may have failed when they tuned their car and ran an egr only block. That's not exactly cause and effect. The thread was how many stage 2 cars have died. I'll just add the egr cooler is plain prone to,failure for all kinds of reasons on these cars, even totally stock. They're delicate and just torquing them incorrectly during installation can crack them. There have been several threads here were people,have had multiple cooler fialures. Heck I m on my 5th egr cooler on this car (52k miles) and except very briefly last week have not run a block and my car was stock.

The dealer mechanics say they see EGR coolers fail somewhat routinely about as common as vibration dampers on X5 -and 335. Others have run a block with no tune only at the egr end of the cooler and racked up 60-70k miles without incident.

Plus it's normal for the egr to run closed on a completely stock car, under many conditions such as full throttle, egr regen, etc.

Running a 2 ended block may increase its reliability if you can uninstall and reinstall it right without damaging the cooler during the process. (My dealer broke 1 out of 5 and 1 was defective out of the box). Best thing to do is remove the cooler totally. But because of the heat it's adds to the engine removing the cooler without removing the dpf could be an issue for some people. These cars won't regen the dpf unless the engine is fully warmed. In cold weather it's possible the car won't achieve proper temps without egr heating to perform a dpf regen. Thermostat failures also cause this issue.

I think running the egr to speed warm up, isn't a bad thing if your egr is healthy. But it's not probably as good as full removal. The real goal with an egr block is to reduce cbu to the point it's not an issue over your ownership period. Even a 100% block won't completely stop cbu, there are other sources of carbon besides egr that end up in the intake.

[Nadir Point]

Originally Posted by remlemasi

If so, doesn't this method make the EGR susceptible to cracking and coolant flowing back into the engine?

You get coolant in the exhaust and a misty white trail out the tailpipes. All details and rhetoric aside, the only really mechanically sound approach to the EGR system is to block it at the manifold and remove the cooler. Anything else is a compromise of some sort, entailing potential problems down the road.

[Thecastle]

Originally Posted by Nadir Point

You get coolant in the exhaust and a misty white trail out the tailpipes. All details and rhetoric aside, the only really mechanically sound approach to the EGR system is to block it at the manifold and remove the cooler. Anything else is a compromise of some sort, entailing potential problems down the road.

I would add, also getting rid of the DPF and SCR at the same time as well.... There is a recipe to the emissions delete and when you stray from it you can have problems and unintended consequences.

Deleting the EGR/Cooler is good! But doing so with an operating DPF could cause problems. Of course you could remove the DPF, but then the SCR plugs, so its really best to go all the way.

I'm running a somewhat unblaized trail, a mostly disabled EGR with DPF and SCR in place.

[Hoooper]

really though running a DPF with EGR blocked is just fine w/regard to regen. There are enough people who ran that way for quite a while that I think its perfectly fine to say that.

[Nadir Point]

Originally Posted by Thecastle

Deleting the EGR/Cooler is good! But doing so with an operating DPF could cause problems.

Exactly what "problems" are you alluding to?

[Thecastle]

Originally Posted by Hoooper

really though running a DPF with EGR blocked is just fine w/regard to regen. There are enough people who ran that way for quite a while that I think its perfectly fine to say that.

I'd agree! The problem seems to be when you mess with the code in the EGR system it sometimes can cause a regen to fail.

[Nadir Point]

Originally Posted by Thecastle

The problem seems to be when you mess with the code in the EGR system it sometimes can cause a regen to fail.

This gets into a grey area of guessing what may or may not be going on. I'll just reiterate something I said in another post not too long ago: The smart approach is to make a choice and go one way or the other, full delete or stay stock. Anything in between is just asking for trouble - especially after you start dumping more soot into the DPF than it was designed to handle. Once you mess with the emission systems to any degree you've crossed the legal line anyway.

Personally, I can confirm the EGR delete did not have any affect on my DPF for over a year. There is an easy fix for the valve motor to preempt limp mode after EGR disappears. The one I no longer need is for sale cheap if anybody is interested. PM for more info.

[remlemasi]

Originally Posted by Nadir Point

This gets into a grey area of guessing what may or may not be going on. I'll just reiterate something I said in another post not too long ago: The smart approach is to make a choice and go one way or the other, full delete or stay stock. Anything in between is just asking for trouble - especially after you start dumping more soot into the DPF than it was designed to handle. Once you mess with the emission systems to any degree you've crossed the legal line anyway.

Personally, I can confirm the EGR delete did not have any affect on my DPF for over a year. There is an easy fix for the valve motor to preempt limp mode after EGR disappears. The one I no longer need is for sale cheap if anybody is interested. PM for more info.

This is harder to say for CARB states. I have the EGR block in place with no deletes. EGR block is simple to remove when I need to, whereas a full delete would be a royal pain to put back to stock when you need to.

[Nadir Point]

Originally Posted by remlemasi

This is harder to say for CARB states.

I would not own a BMW diesel if I lived there.

[remlemasi]

Originally Posted by Nadir Point

I would not own a BMW diesel if I lived there.

I know. But I love the car too much.

[Thecastle]

Your best option in my opinion in a carb state would be to buy a second dde. Keep one stock and one tuned maybe with egr delete. Don't block the egr, and just swap the computers before inspection. More power, less cbu, and easy revert back to stock. Swapping engine computers on these cars once you've done it is pretty easy. Less than a 20 minute job I'd say.