Looks like we have had some good input from the other thread from guys who have experience with the EGR delete mod. Perhaps we can move some of the dialogue that we had from the other thread here where it is more on topic? I'll kick it off...

 

Quote:
Originally Posted by isstay


"Nice video, Josh.

Did you notice any oil inside the hose going down to turbo intake while doing the surgery?

I am asking because I am dealing w/this issue, which MB says is normal, but I do not like it. Oil vapor gets to intake manifold and coats it, good thing my EGR is unplugged now and no soot can make it to the intake anymore to mix w/oil vapor and form sticky goo substance. I have been dealing w/small leak from the gasket (part #59) between intake and so-called mixing chamber ever since I purchased the car. It is fixed now (after friend made me ticker gasket), but I had the opportunities to look inside the intake while changing it and I do not like what I found – black sticky substance (like tar) above the junction between charge pipe and EGR cooler.

I even replaced the Cyclonic oil separator thinking that the pressure control valve is not functioning properly, but there is still some oil into turbo intake. "





My reply:


Actually I did notice oil in the outlet tube of the separator. It had a nice coating inside of the tubing, and it was very apparent that liquid oil is getting through. The cyclonic separator is faily effective, but certainly not 100% under all operating conditions. I may actually incorporate a lower intercooler air bleed line(1/8" ID) in the lower intercooler much like I did with my TDI to ensure that a slug of liquid oil never enters the intake tract causing hydrolock or runaway.

I am also partially concerned about the coating of oil and soot in the intake on mine too especially as it relates to the swirl flap functionality. I have read that malfunctioning/sticky swirl flaps can cause sudden onset of rough idle, and other driveability problems. I want to do my best to make sure this doesn't happen to me, and perhaps reverse some of the buildup that may have accumulated so far. Part of the solution seems to be deletion of the EGR and then the other part would be reducing CCV oil vapor entering the engine. How did you delete your EGR by the way?

 

Josh - prior to moving the thread you mentioning adding a circuit to turn the EGR delete on and off without CEL. Alex on the UK thread said that as long as you throw the switches separately in the correct sequence, there should be no CEL when done with the engine running. Alex was talking about adding circuitry to do just this, having the trigger be a threshold for a minimum engine temperature.

To date I don't see any attempts in the thread to do that.

 

Right, I do recall reading about that. It only makes sense, and with such a simple addition of a super simple relay type circuit you can have the best of both worlds. I will most likely begin to gather components together here and look into where I might install it. I have even considered making one and poting it in epoxy to keep it sealed. I haven't really poked around too much in my cars fuse boxes and all yet. I would like to familiarize myself with them, and apply some dielectric grease to the fuses and relays to keep oxidation at bay. Older cars need to have the fuses/relays wiggled around now and then to help maintain a low resistance conection between them.

 

Looks like I need to start gathering components. I have a large assortment of resistors to work with, so no issue there. I will also need to figure out how to use a 2N222 since they are much more common on this side of the pond. Anyone have any ideas on the 2N222 circuit?

 

Ok, after a bit of a refresh on transistor circuits I have chosen to most likely base my EGR emulator on the 2N3904 which is a very common general purpose transistor. It's also an NPN like the original BC337 in Alex Crows circuit. I went through the schematic and labeled the base, emitter, and collector so I will make sure everything is wired correctly. I will also be sure to use a location for the circuit that will also have very moderate temperature swings so resistance values and gain won't change too much.

 

a friend of mine gave all the bits. the transistor was some other npn, don't recall what it was.

 

I am going through some information on how exactly to wire the EGR emulator/delete circuit, and found the following info from Isstay:

"The intercooler tanks are flat w/it’s bottom end, so it will not hold any oil, I already check mine - empty. Yes I used the schematics from the link above, just will add one thing – all brown and red wires from engine harness end on same terminals in the fuse box (you will find bundle of red or brown wires connecting to a single big red or brown wire), does not matter which one you will tap. Wires from MAF (red/blue) and EGR (yellow/grey) needs to be traced. It work from first time, w/o any CEL. "



From this information it looks like the PWM signal is taken from the EGR wire that is Yellow/Grey(EGR Pin 1). Can some one confirm this. I have all of the other wires pretty much figured out as far as where I will tap them etc, but the PWM wire I am uncertain about. I'm looking forward to getting this up and running fairly soon hopefully. Once I have the technical construction side of things figured out it should progress fairly quickly. Maybe I will make a video of the construction/install when it is all done.



..

 

That is consistent with my understanding. Use an ohmmeter to confirm.

-Bill

 

Yes, you have to tap the correct yellow/grey and blue/red wires otherwise you will get CEL (I used ohmmeter). Ground (brown) and 12V (red) are not specific; you can tap any as they end on same terminal.

 

As always, super helpful. Thanks!

 

I'm the guy from post 121, it has been working fantastic since 11/2011, no limp modes or check engine light, I haven't check on fuel economy since I have a lead foot

Delvi.

 

Cool, good to hear from you on that. I thought I would start with your post since it was 05/06 E320 CDI specific. Are you having any trouble with blow off from the disconnected EGR?

 

Tested the CTS, and it is a NTC(Negative Temp Coefficient)device. I noticed as temp went up, the resistance went down. Room temp was around 2.2K Ohms. FWIW

 

Ok, looks like I now have found and verified my resistors and their respective resistance values. All I have to do now is find/scavenge a 2N3904, assemble it, pot it in epoxy, and install it. I think this first iteration won't use the "Dynamic EGR" functionality which requires tapping into the CTS, and creating a coolant temp driven on-off switch. I'll use the KISS principle first

 

I do not see why you want it to work at all since does not do any good for the engine? Since I unplugged it, I do not see soot cloud in my rearview mirror when I step on the gas pedal. I know you are worried about warm up times being longer, but what happens to engine w/SCR, some of them do not have EGR. MB removed EGR from it’s big diesel engines some time back in 2005-2006 and they where saying that EGR decrease trucks mileage and shortens engine life spam, now w/new emission standard EGR is back, but Caterpillar for instance does not put EGR on any of the diesel engines they are producing. They do reroute some of the exhaust gases back to the combustion cycle, but only after, they pass through DPF. I would like my engine to warm up faster too, but I do not like the idea of dumping all this soot back into it, and producing even more, because of lowered oxygen content leading to incomplete burning process. When an engine is cold, EGR is open 100% and reroutes big amount of exhaust gases to the intake, thus lowering the power output and gas mileage.

 

Next time I have the cover off the engine and the engine is cold I will start it up, and put my hand on the EGR cooler and compare its temperature vs time to the coolant temperature. It will be interesting to see the difference. I have also heard that some of the other vehicles don't use the EGR, or implement it in different ways(post DPF for instance). I would venture to say that they have other heat exchanger devices in the system that exchange the exhaust heat to the coolant system during startup. That's the real issue, to get to operating temp as quickly as possible-EGR cooler is definately not the best way but it took care of two of their design goals originally. It would actually be nice to have a exhaust to coolant heat exchanger that was thermostatically controlled to reduce warm up time. Adding a coolant heat storage device would be icing on the top. lthough I must admit the way they designed this engine compartment it really tends to hold the heat really well.

 

I believe I will use the somewhat standardized wiring color scheme like Alex Crow used. Red for 12 V, Blue for PWM, Yellow for MAF, and Black for ground(O V). I will be swinging by Radio Shack this afternoon to pick up part numbers:

276-2016 (for the 2N3904)

276-1103 (for 1N4004)

I will also pick up some clear two part epoxy so I can waterproof/pot the circuit. I have a nice heat shrink that has weatherproof coating in it so that will be used also.

 

I may have been one of the first to install this modification on my 2005 E320cdi. After 6000+ miles, I have had no issues. I welded the egr valve flap closed so that there was no possible way that exhaust gases could unseat egr valve. Engine seems to run better every time I drive the car and i saw no difference in warm up times. If you have a defective egr valve, this mod will save you about $900.

 

Great input! Thanks for the info on the warmup times too. Have you noticed and MPG gains or that the oil stays cleaner longer? I see over on the MB Owners Forum you mention a 2 MPG increase, is this still holding true?

 

Update:

Finished up the construction of my electronic EGR delete circuit for the E320 CDI last night. I potted the circuit in 5 minute epoxy, and finished it up with heatshrink tubing. This thing will definately be water tight! Bad thing is that I'm not sure it will work since I didn't test it out before I sealed it. I know for sure that I don't have any shorts, and I paid close attention to where the Base Collector and Emitter connections went. I plan on using Alex Crows electrical troubleshooting tests to verify I have similar ohm readings from lead to lead as he did. I had to use a different transistor that the original called for so hopefully it will all pan out. I used a TIP31 instead of the BC337 listed in the circuit. Good thing is that even if it fails, I have extra components available that I can create another one with. Some time soon I will be installing/testing and and look forward to the potential of higher MPG's and cleaner oil. Time will tell I guess.

 

Are you going to do an awesome write up when you finish all this EGR work? :bowdown:

 

It is really hard to say since I installed it when the weather started cooling down here in Virginia. However; I did not see a drop in mpg so i assume i am still getting about a 2 mpg increase. The car definitely runs better and I know I won't have intake manifold gumming up problems.

 

Just noticed you asked about oil being cleaner. Don't know about that since I was about 3000 miles into the oil change interval when I did the mod.

 

Ok, gotcha. What is you MPG anyway? Looks like just cutting the PWM wire to the EGR valve and leaving the EGR valve plugged in gets us around having the blow off effect right?

 

Well tonight I took the time to install the EGR delete circuit -for off road testing mind you I have no CEL's and all seems to be well. I did notice that the warm up time was lengthened by 30-40% however, although I did have the engine cover removed during the test run. Not sure how having the cover off effects warm up times. I will be able to retest it tomorrow with the cover on and see if I still notice the lengthened warm up. I believe I also noticed a little more boost lag, and perhaps BOV effects. I will be looking into this further for sure.

I ended up substituting a couple components in the circuit for some that were available locally. I used the TIP31 Transistor from Radioshack. RS part number 276-2017. I went ahead and filled up this evening since I was at a quarter tank so this next fillup will be post EGR delete. Before anyone runs out and gathers the substitute components I used give me a bit of time to make sure it works well over the next month or so. Everthing should be ok since the transistor I used is rated for more current than the original device in the circuit.

 

This afternoon I was able to find a couple 12V DC relays(DPDT), and a couple 75 Deg C bimetallic thermal switches on Ebay. I believe I will use them to create my "Dynamic EGR" circuit. They are from China, so it will be a while before I get them. Now it's time to further refine my circuit so its simple but effective that way once they arrive, I can put them to use.

 

What is BOV?

 

BOV – blow of valve, if you notice EGR opens against exhaust gas flow and some people are concern that turbo pressure will be able to push and open valve an there will be loss of pressure to exhaust side. I do not think that this can happened because of the valve spring plus exhaust gas pressure.

 

I haven't taken the time to measure the radius of the EGR valve plug. I estimate it at .75"(from memory) radius which gives approximately 1.76 square inches surface area. At 10 psi boost that would give 17.6 lbs of force pushing against the plug, and the only opposition would be the spring. Not sure what the spring rate is, but it may be fairly small. If it's smaller than 17.6 lbs for instance in this example than it could start to open at that pressure. Also, over time the spring rate may change due to vibration and heat so as it gets older it would tend to open sooner.

The above is assuming we are at atmospheric pressure on the other side of the EGR plug, but in reality we are some value above atmospheric due to turbo, and exhaust back pressure. Still, if we boost to a high enough pressure it can still potentially cause issues. What are typical boost pressures of the 2006/2006 E320 CDI anyhow?

 

By the way, I ended up asking some of the guys on the original CDI3 EGR delete thread to verify that a cut PWM wire to the EGR valve will cause the electric motor to assist the shut off force to the EGR. A couple guys responded and confirmed that it does forcibly shut it off, so that would mean that my slight reduction in power is coming from something other than BOV effects. My resistance value for R3 ended up being around 627 Ohms instead of the 643 Ohms listed in the schematic. This is most likely due to the fact I used 5% tolerance resistors, and they were a bit on the low side. Since that resistor is a lower value than it should be, it allows the EGR delete circuit to pull down the MAF voltage a bit too low making the engine believe it is taking in a smaller amount of air and it reduces fueling accordingly. If my thoughts on this are correct, than adding a small resistance value(0-50 Ohm variable resistor) in series with the wire going to the MAF should correct this, and allow me to dial it in so I don't have any performance changes. This added correction resistor can also be added easily without destroying my original circuit.

 

Thanks for defining BOV. However; if I'm not mistaken,the EGR valve opens WITH exhaust flow. It would be exhaust pressure opposing EGR spring pressure plus intake pressure or vacuum as the case may be.

 

The EGR gas flows from underneath the EGR valve right? Also, I believe when the EGR valve opens, it extends the plug. Once it's unpowered the spring retracts it.

..

 

Yes, you're right. I was confused and then I was more confused. Thanks for the de-confusion.

 

Actually, it was kind of funny when you posted. I had the "Oh Crap" moment and had to rethink it through to make sure I was on the right track.
I can sometimes get a little wonky in my thinking, and appreciate a gut-check every now and again. Thanks!

 

Looking at the 2005 E320 CDI cooling circuit I see that the coolant obviously flows through the EGR cooler. Since it is in such close proximity and connected partially to the air intake system, I can see how it would tend to radiate and conductively transfer its coolant system derived heat to the intake air stream. With a "Dynamic" EGR setup(one that only allows EGR functionality during warmup only-which I intend on construcing for my car). Why wouldn't it be possible or potentially advantageous to eliminate coolant flow through the EGR cooler once the EGR is turned off after warmup?



I can see the advantages of being:

1) Cooler intake air stream
2) Reduced coolant system inventory after warmup
3) Reduced thermal loss to intake structure


Disadvantages:

1) Added complexity of additional components(coolant bypass valve)
2) Perhaps marginal improvements in power?