[dixy2k]

Would it be better to shift manually while driving in the city (lots of stop lights, slow traffic, etc)?
Just so the engine would rev up more than usual?
Driving normally in D the car would not rev more than 2000 RPM. Lots of Idle time too.

[Purplehayes]

Originally Posted by dixy2k

Would it be better to shift manually while driving in the city (lots of stop lights, slow traffic, etc)?
Just so the engine would rev up more than usual?
Driving normally in D the car would not rev more than 2000 RPM. Lots of Idle time too.

Excellent question. I do wonder if driving it in manual is harder on the transmission than in automatic. Manual certainly is more fun!

[dixy2k]

Finally got my car back today.
I really hope they fixed everything this time.

SCR, particulate filter and diesel filter were replaced.

They found diesel fuel inside the SCR, which was also clogged.
My guess is that I did not get the regeneration to clean the filter. ECU fault?

[F32Fleet]

Originally Posted by dixy2k

Finally got my car back today.
I really hope they fixed everything this time.

SCR, particulate filter and diesel filter were replaced.

They found diesel fuel inside the SCR, which was also clogged.
My guess is that I did not get the regeneration to clean the filter. ECU fault?

Bad injectors my guess, but I don't know how diesel can make it past the DPF with out burning up.

[dixy2k]

They also replaced the diesel filter.
I am not sure if they wrote down accurately what they did.
I believe in this case the diesel filter would be the diesel fuel filter. It may also be the diesel particulate filter. I just don't know. The SA had no idea what sort of worked was performed on my car.

[F104]

here's a BMW video

the DPF itself is a combination of oxidation catalyst and the filter. The oxydation catalyst sets the unburned fuel in the exhaust gasses during a regeneration on fire to heat up the filter and burn the collected soot to ash.

However it can't cope with too much fuel (or oil, being hydrocarbon too), resulting from say a leaking injector, blown turbo seal etc. In that case the fuel/oil goes thru the oxidation catalyst without being burned, and both the DPF, and the SCR get polluted with fuel / oil. The DPF might recover from this after an succesfull regen, but the SCR won't.

[Puerto Rican 335d]

Nice video

[locolobo]

Ecotune with EGR delete = no soot entering intake

[ihbase]

Originally Posted by F104

What's the purpose of this thread? You claimed no carbon (=suit) build up on your engine in undefined mileage. You didn't answer my post #20 as how you established that.

I tried to educate people in post #38 (or so), but seems a lost attempt.

Now you're about glazing (nice quote though), which has no reasonable relation to suit build up. Glazing causes blow by.

F104: Why so uptight?

The theory on glazing (or "wet stacking") and carbon deposits on the intake side is that blow by and poor combustion processes increase carbon deposits. In particular, the potential for deposits related to the combustion of oil is increased when crankcase pressure is raised due to glazing.

If you believe that trying to combust engine oil at low head temps would result in increased carbon deposits, the theory makes sense.

-Mike

[F32Fleet]

Originally Posted by F104

My question in post #20 has not been answered by the OP. So do we have a 100.000 km (mls?, in one year? second hand?) engine really without soot build up, or a wrong diagnostic?

This is not model/engine specific. Diesel engines with EGR recirculate particulate matter (soot) back to the intake. As some have indicated, that is based on a steady state map. If you accelerate above a certain minimum rate (which is really low), EGR is cut off. Also EGR is cut off when outside the emissions box (eg where they measure emissions, or on a EPA cycle where it has little impact on the total). On my 320d that steady state limit is at 2390 rpm in 6th, or about 85kph indicated. Above that 85 kph level road there is no more EGR requested. So that has been my cruising speed. On a 330d/335d, I'd expect that rpm to be higher as you'll have less load on the engine. I do 90% highway. And even with that my intake system is not very clean. I've an ODB reader showing EGR position.

The EGR recirculates dry soot. It comes out of the engine, pre turbo, at 500C or so. That has to be bone dry. So it leaves a dry, powdery coating. The problem starts on the back side of the throttle valve, where this dry stuff mixes with intake air containing oil from the breather.

Oil Catch Cans...certainly a move in the right direction but I have my doubts. Search for "coalescing filters". A bit of wire mesh in a coffee cup sized tin is miles away from where the heavy duty truck industry is moving. And there is flow restriction, too much restriction and these won't flow. Great from no oil carry over perspective. Not so great from a oil perspective, where the water vapours etc can't escape.

I'm running a coalescing filter given to me, stuck in a housing made from diy shop bits.The filter element is I think 4" dia, 8" long. Last time i took it apart it was black on the outside, oil on the bottom, and as new on the inside after at least 20k mls.

And here's the info from Pierburg, you might recognize the components under the hood, as Pierburg supplies BMW and many others. It shows the basic chart where EGR is in operation.

Just noticed your post. Being that you're in Europe how prevalent is carbon buildup in passenger car diesels?

[dixy2k]

At 2000 RPM I am already at 80 mph. If the EGR valve is closed above that PRM, I am out of room on the freeway. Even at 80 mph I am pushing it.

[335dFan]

Originally Posted by dixy2k

At 2000 RPM I am already at 80 mph. If the EGR valve is closed above that PRM, I am out of room on the freeway. Even at 80 mph I am pushing it.

No problem, just cruise at 80 mph in 3rd or 4th gear. Problem solved.

[Pierre Louis]

Originally Posted by Socom

Just noticed your post. Being that you're in Europe how prevalent is carbon buildup in passenger car diesels?

My French nephew mentioned that it is known at least for the new Peugeot diesels to build up carbon if they are used primarily in city driving and not "opened up" on the highway.

[F104]

Originally Posted by Socom

Just noticed your post. Being that you're in Europe how prevalent is carbon buildup in passenger car diesels?

same thing from BMW to Land Rover.. But maybe the fact we have mostly smaller displacement engines running at higher loadfactors, and thus more outside EGR operation, results in seeing the problem only at higher mileages.

Originally Posted by 335dFan

No problem, just cruise at 80 mph in 3rd or 4th gear. Problem solved.

No, the EGR map is speed/load dependent. When one shifts down for the same speed, the load decreases, and it wants to see a higher rpm. That was one of the first things i tried too
My post should have said mph, not kph. It's just under 140 kph indicated in 6th when it comes out of EGR mode

[Vreimann]

Originally Posted by F104

No, the EGR map is speed/load dependent. When one shifts down for the same speed, the load decreases, and it wants to see a higher rpm. That was one of the first things i tried too
My post should have said mph, not kph. It's just under 140 kph indicated in 6th when it comes out of EGR mode

If that speed is true for closed EGR, you made me a happy camper cause I drive a lot in that range on highways sections. Do you know specifically the km/hr it shuts down?

[TDIwyse]

Here is a map of the EGR utilization. It's for the M57, but with both high and low pressure EGR (so probably from the X5). I haven't found a 335d (with only high pressure EGR) specific EGR map.

Based on this map, I'm not sure how you can assume for a given power requirement to maintain a certain speed, how you can use a different gear to shut off the EGR. The higher the rpm, the less torque you need to get the power you need for the speed you are going... I think you'll always be getting lots of EGR utilization unless you remove the EGR path. Unless you are above ~4000 rpm...

[dixy2k]

I am trying to stay within the maximum torque range (1750-2500 RPM) with occasional burst up to 3000-4000 RPM.

This is way different than what I used to drive like. In the past I used to keep the RPM as low as possible, rarely at 2500.

[F104]

Originally Posted by ihbase

The theory on glazing (or "wet stacking") and carbon deposits on the intake side is that blow by and poor combustion processes increase carbon deposits. In particular, the potential for deposits related to the combustion of oil is increased when crankcase pressure is raised due to glazing.

If you believe that trying to combust engine oil at low head temps would result in increased carbon deposits, the theory makes sense.

Yes you're absolutely right and my comment was wrong. Higher blowby does imply you get more oil into the intake

Originally Posted by Vreimann

If that speed is true for closed EGR, you made me a happy camper cause I drive a lot in that range on highways sections. Do you know specifically the km/hr it shuts down?

Mine shuts down at just under 140 kph indicated, 132kph GPS. But I have a 320d. A larger displacement engine means higher speed. Just looking at it simply, a 3 ltr is 1.5 times the size of my engine. Engine load is related to the square of speed, the square root of 1.5 is 1.22. So my guess would be the 330/335d requires 1.22 * 132kph, or 161kph before it comes out of steady speed EGR mode.

Originally Posted by TDIwyse

Here is a map of the EGR utilization. It's for the M57, but with both high and low pressure EGR (so probably from the X5). I haven't found a 335d (with only high pressure EGR) specific EGR map.

Based on this map, I'm not sure how you can assume for a given power requirement to maintain a certain speed, how you can use a different gear to shut off the EGR. The higher the rpm, the less torque you need to get the power you need for the speed you are going... I think you'll always be getting lots of EGR utilization unless you remove the EGR path. Unless you are above ~4000 rpm...

Yes my point too. If that map would be correct for the 335d you would need to be at even 180kph (115) mph constant speed to be out of EGR mode. To calculate the torque requirement at 112mph (which is a nice round number of 50 mtr/s or 180 kph):

- Air resistance is 1/2 * 1.2 (mass of air at 20C) * 50^2 * frontal area of some 2 mtr2 * Cd of 0.3, or 900N.
- Rolling tyre resistance estimated at 1,25% of weight of car (1700kg), or 210 N
- Total is then 1110N.
- To generate that wheel traction you need 355 Nm wheel torque (0,32 mtr wheel radius)
- With 0.69 (highest gear ratio) and 2.81 diff for the 335d, overall ratio is 1.938. Therefore 183 Nm engine torque.
- Driveline losses estimated at 5Nm base value (altenator etc), plus 2% of the driveline torque. So 5 + 4 = 9 Nm
- New total is now 192 Nm at 3200 rpm for this speed (112mph..). Just on the edge of the EGR area on that map..

Just as a cross check, same calc with 75mtr/sec (270 kph/4800rpm) matches the value on the 335 torque curve nicely. So assumptins seem to be correct and 270 would then be your topspeed without the limiter (given the 20C temp, tyre diameter etc).

[daveN007]

While interesting, all of this is completely insane.



What kind of moron would buy a 335d instead of a 335i knowing that you have to drive the 335d in a way that makes the reason why you bought the car irrelevant?

"What about all that massive torque?"

Hello? A 335i is quicker and can be tuned just as easily.

The point of the 335d is that you can get good fuel efficiency AND good performance.

To say that I am hurting my car by cruising at 70-80 MPH and enjoying the 600 mile range it gets me is...silly. It is a design issue and it isn't our fault. :roll eyes:

I will continue to drive in a reasonable fashion and hold BMW to account for quality issues.

[F32Fleet]

Originally Posted by daveN007

While interesting, all of this is completely insane.



What kind of moron would buy a 335d instead of a 335i knowing that you have to drive the 335d in a way that makes the reason why you bought the car irrelevant?

"What about all that massive torque?"

Hello? A 335i is quicker and can be tuned just as easily.

The point of the 335d is that you can get good fuel efficiency AND good performance.

To say that I am hurting my car by cruising at 70-80 MPH and enjoying the 600 mile range it gets me is...silly. It is a design issue and it isn't our fault. :roll eyes:

I will continue to drive in a reasonable fashion and hold BMW to account for quality issues.

Agreed. We would have figured BMW had worked this out with their years of experience. Maybe even a cost effective means of cleaning it.

[F104]

Originally Posted by daveN007

While interesting, all of this is completely insane.

What kind of moron would buy a 335d instead of a 335i knowing that you have to drive the 335d in a way that makes the reason why you bought the car irrelevant?

Yes today I don't disagree either. My choice for the 320d was based on local taxes, the fuel economy, and it would go (tuned) easy to 120mph in Germany. It will do 145 mph flat out, but even in Germany difficult to find the open road to do that, unless you want to test your brakes
Today a 328i can do the same, but for me it has a one time $ 5000 tax penalty vs. the 320d.

[Timujin]

Originally Posted by dixy2k

Would it be better to shift manually while driving in the city (lots of stop lights, slow traffic, etc)?
Just so the engine would rev up more than usual?
Driving normally in D the car would not rev more than 2000 RPM. Lots of Idle time too.

I am exclusive in DS mode now. I am also running RPMs up and manually shifting in the city.