MB Paba,

I really think you are making this MUCH more complicated than it needs to be for our '97's... I've been running that setup for years now and haven't had a single issue. If you install a decent filter, you'll be fine. The EGR closes above a certain RPM and up to WOT anyway. Watching the operation of the EGR, the valve only appears active while the engine is idling. As soon as the rev's start going up it's closes.

Am I missing something?

Yes, I would definitely seal that circuit but I don't plan on it being permanent - I think I'd prefer to add some more ECM I/O 'adjustments' before then.

Michavelli,

I guess I may be making too much of it. Just would like to do it best, if possible.

Evan,

I have removed the components so am ready to proceed. I will try to post a couple of pics I took of the EGR and the MAP sensor.

Thanks for taking a look at it!

OK, I need to learn a little about the way your car operates. You'll need a mity-vac and a volt/ohm meter.

1. Put a 'T' in the line going to the EGR transducer and use the mity-vac to measure the vacuum with the engine running. You want to use a 'T' because you don't want to alter the EGR operation and set a code at this time. Note the vacuum level.

2. Shut off the engine and pull the 3 wire connector on the EGR valve. Use your volt/ohm meter set to ohms and measure the resistance for the following pin combinations:

1-2
1-3
2-3

3. Finally, attach the mity-vac to the EGR line and pull the same amount of vacuum you noted in step one. Re-test the same three combinations of pins on the switch on the EGR.

Report all six values here.

It sure takes the meter awhile to settle to a voltage, sometimes kept floating. I did measure the results at the 8" point as well. They were:

1-2 3.18"
1-3 2.46"
2-3 2.24"

Let me know if you want further data.
Thanks, Evan!

Evan,
here is another happy customer. I send you the mail I received today from another diesel enthousiast person, driving a of course a E300TD. This is great. I didn't do anything yet as I am not really an electronic person but I should look into it properly.
Thank you from me and thank you from DM:
Olivier
I've performed the EGR delete as shown in THIS thread, and it appears to work very well.

It makes sense that the MAF voltage can be dragged down by the EGR Low signal, I just hadn't got round to thinking about it.

I'm not a member of that forum so can you please say thanks to KarTek for me, for putting the research into this.

regards

Thank you Evan
 

I received the Mod today made by DM as I don't know much about electronics, it was easy to set up. I drove around (highways, city, coutry roads) with the EGR vaccum pump disconnected and no limp mode, nothing. A perfectly running car.
Evan, thank you so much for putting this all together. This is great.
Happy breathing clean air for the car now. :D
All the best.
Olivier

Just tell the computer the engine is cold all the time?
 

Wouldn't it be simpler to just disconnect the engine temperature input into the computer and install a dummy resistor to simulate 'cold engine'. That would stop the computer from telling the EGR to actuate.

What else is fed by the engine temperature sensor?

-Jim
(PS. I am asking because I have a W140 with the 603 engine. Your solution will not work for me and I am trying to find an easier fix for my engine.)

Not sure about the older cars but I believe simulating a cold engine on the W210 and later models will cause the Engine Control Module to inject a richer than necessary mixture....
smoke........... :(

Rich mixture on a diesel? I don't think so.

How about Richer mixture???

My 98 Idles cold at 0.3 gallons per hour
and
Idles warm at 0.1 gallon per hour...

Simulate a cold engine all of the time and that is more fuel going out the tail pipe... Correct???

At idle speeds, there is an excess of air in the cylinder which cannot and does not combine with any fuel. "Mixture" for a gasoline engine means just that, the actual constituents of the gas in the cylinder, but has no meaning for a diesel.

What you mean is "inject more fuel" which is also what happens when you press on the foot feed. So you can fool the computer -- with your foot.

More fuel means more power on a diesel, until you get to the point where you have insufficient air to burn. So more fuel means that you go faster. You will naturally back off with your right foot to compensate.

You do get an incomplete burn with a cold engine, but this is a completely different thing, and it is not correct that you can exploit it for more power. All you'll do is increase your idle RPM -- until the computer notices (that would be right away) and moves the rack just a bit.

Ok, I understand all of that...
The computer also controls the volume of air available to the engine thru' actuation of the waste gate... Does it also limit air to a "cold" engine as it adds more fuel????

At idle, the computer cannot control the turbocharger because there is insufficient exhaust velocity.

The only reason to limit air to a diesel is to artificially create an intake vacuum to help with the EGR system. The NA 606 has a flap to do this, but the turbo does not. Thus, on the turbo model, the computer can only limit the air by not running the turbocharger, and at idle, the turbocharger really doesn't matter. It is just a slight restriction in the exhaust, and provides no boost.

At high speed, the turbocharger wastegate is actuated to control the impeller speed, mainly. More air never hurts a diesel; it's the injected fuel that moves you.

And no, the computer does not limit the air on a cold engine at idle. Yours takes more fuel at idle because that's how much fuel it takes to turn the engine over at idle speed. The engine idle speed is controlled exclusively through the rack position, which translates to gallons per hour. The air is not restricted. The rack modulator is, well, modulated to give you the proper idle speed. And when you press the pedal, the rack modulator is again, well, modulated to provide more fuel. Until you start providing substantially more fuel than is required at idle, which gives substantially more exhaust gas volume, you can have no boost.

Hey... I've been thinking this over and it comes down to the fact that the W210s are fly by wire and everything goes thru" the Engine Management Module... So, what exactly happens when you simulate a Cold Engine???