Most MB's of the period do monitor EGR via Airflow readings.

There was a very simple circuit that some guy designed to fool ECU when EGR was "open" it applied a resistance to the MAF reading, .................

You'll have to search, I'm pretty sure I saw it on Benzworld Forum somewhere, it was a CDI Engine he did it to .........................

Now that said, you may be able to switch off EGR Monitors using SDS Developer, first you have to unlock the Motor ECU, I have a document that explains exactly how to do that unlocking on your SDS, let me know if you want it .............. Note that it isn't a Virgin procedure, it unlocks the Motors Version Codings

HTH

 

Thanks for the information Dave, yes if you don't mind I'd be interested in having a copy of the document that describes how to unlock the motor version codings

I would keep the EGR function on a gasser, they do their job very well and it is not nearly as detrimental as it is on a diesel.

EGR have their own function, which as you mentioned, lowers the temperature of the exhaust gases, decreases the production of NOx and CO2 during the combustion cycle, and also have a mild effect on the gas mileage (increased MPG) when cruising. All in all, not actually bad.

In diesels, it's a whole different story, and EGR, while massively helpful (even more so on diesels compared to gassers), also create massive amount of carbon build up, which can be a serious pain in the butt to clean.

Up to you, really. You can disable with SDS....pretty much the only way to do it, because the car will otherwise throw a CEL if it detects EGR non-op.

Thanks for the reply I agree with everything you say. I guess 145k miles / 22 years is alot of time for it to build up it will be a long time before it gets dirty again and even then it may not inhibit any performance etc.

I may drive it and gauge the fuel economy etc then try coding the EGR out and seeing if there is a perceivable drop in MPG. If there was not any noticable real world drop in MPG I would then leave the EGR off.

Part of the reason for splitting the manifold was also to address the hard as rock and broken vacuum line up front which MB don't list. You have to make your own adaption of it.

And the plastic brake booster connector on the back of the manifold was loose and not actually sealing. Also not listed by MB (the actual main component has no part number it is supplied in a new intake manifold only)

Came up with a brass air line fitting that works, viton seal ring etc much better than the old version.

 

I would keep the EGR function on a gasser, they do their job very well and it is not nearly as detrimental as it is on a diesel.

EGR have their own function, which as you mentioned, lowers the temperature of the exhaust gases, decreases the production of NOx and CO2 during the combustion cycle, and also have a mild effect on the gas mileage (increased MPG) when cruising. All in all, not actually bad.

In diesels, it's a whole different story, and EGR, while massively helpful (even more so on diesels compared to gassers), also create massive amount of carbon build up, which can be a serious pain in the butt to clean.

Up to you, really. You can disable with SDS....pretty much the only way to do it, because the car will otherwise throw a CEL if it detects EGR non-op.

 

The EGR isn't the source of carbon deposits in the intake manifold, EGR gases AND oil mist from PCV mixing together is the issue.

Check the operation of valve and consider the installation of a Mann Hummell ProVent.

 

EGR gases AND oil mist from PCV

Good point

I'm old skool, I don't like breathing my own farts so nor should my Engine .................

That said I haven't disabled any of mine, would only do it if need arose

Joe, pm me an EMail address and I'll EMail that file to you

BTW, I don't think SDS turns the EGR function off, I think it just stops the fault monitoring, you would need to physically install a wee blocker plate on the back where the pipe is

That said, I have never tried looking for an EGR Off in Developer, I just saw the Monitoring when looking at other monitors
HTH

 

No air pump,how is that possible?My car is made in ´98,and has a pump.There is a good reason why these systems are there.

 

It never had the secondary air pump from factory! Maybe as it was delivered in UK they had different emmisions legislation at the time in 1999 that did not require the air pump? In any case it was never there.

 

The spark timing is predicated on working EGR. You can't just delete it without adjusting several parameters including spark timing.

I once deleted EGR on a gas engine - long story involving an Oldsmobile V-8 engine swap. The worst pinging you've ever heard was the result. Horrible. Like marbles in a coffee can on a paint shaker.

Had to re-curve the distributor advance to pre-1972, which had much less total advance to get the pinging under control. Still wasn't quite right...

Ultimately, I put the EGR manifold back on, along with a Quadrajet and the EGR curved distributor timing.

All was well. No more marbles in a can. Better power, too, as fuel delivery and ignition timing were matched to the presence of EGR.

 

Thank you for the advice!

I have been thinking about this and considering I'll only be doing about 1k miles per year it is not worth the possible faults / hassle of trying to disable the EGR.

Therefore I will put it back together as it was from factory and leave it alone in this case. It will take several decades to build up like it was and even anyway did the gunge buildup really affect the performance? I would say not at all in reality

 

I'll bet that Oldsmobile never had Knock Sensors The MB Knock Sensors allow it to run as advanced as can be for any given load, I know that from tuning the m113 in my SLK, also applies to other Engines / Management with Knock Sensors

 

Glad for this thread, as this weekend, I'm going to take apart the intake manifold for the new project 2006 S500's engine and clean it out. Also going to replace all the rubber hoses that go to it; they're in pretty sad shape. Fortunately, I'll be driving the 2003 S430 to @v12tt's place to work on it, so I'll have a working model for comparison. Bringing @JC220's pics as a guide to help.

 

OK, the intake manifold is apart. It had some carbon and oil in there, but not much oil. It got the kerosene/toothbrush treatment, followed by some engine degreaser and a good washing. It's nowhere as good loolking at JC220's, but it's cleaner than it was...

...but now, I've got a few questions.

1.) There are two pieces that appear to sit in the "larger half" of the intaken manifold, not actually connected to anything. I get the impression that they're supposed to be able to move when the variable intake manifold flap actuator starts actuating, along with the flaps themselves. When I opened it up, things shifted around, so I'm not sure how they're supposed to go back in. What's the proper way to reinstall those two pieces? I've got them "circled" in green in the below picture.

2.) There are also two pieces in the "larger half" of the intake manifold that JC220 got out and cleaned. What I also don't know is how to take those out for proper and thorough cleaning. Those parts are "circled" in green in the below pic. How does one get those out safely?

3.) Those pieces in question #2 appear to matter a lot for dealing with what looks like one of the other rubber vacuum hoses that goes into the bottom of the "larger half" of the intake manifuld. Is that true, and is that hose a special hose? If it isn't a special hose, would a piece of normal automotive rubber hose of a similar size work as a replacement?

 

1: As @Deplore said they only go one way and are captive by the rest of the manifold going back together.

2: Those sections have RTV all along the edges which makes them dificult to pry out. What I did was spray lots of Carb cleaner aeresol in around these edges to soften the RTV. (Since carb cleaner is about the most potent automotive cleaner I know) Then use 2no large pry bars and gently apply even pressure until you feel them pop free.Be careful not to crack the fragile castings.

3: Yes the rubber vacuum hose is a common failure point. Mine was all broken up and badly perished even though I did not have a known leak or fault code. Note that this hose does NOT appear in EPC therefore MB do not sell it. They want you to buy the whole manifold asssembly instead.

I just took new small bore fuel hose which was the same inner diameter of the original vacuum hose (Because it is braided and resistant to fuel so should hold up well) and cut down a larger bore fuel hose section so it matched the thicker upper part of the original hose assembly. Then super glue that over the smaller hose - it is a tight fit so took me a couple goes to get right! Then you slip the smaller hose through the intake, mine was a tight seal then the larger hose butts against the lower clam shell and when you set the upper part down in the little spigot drops into the hose and it is held up tight to seal.

I recommend using a quality aeresol type RTV tube for these manifolds. I used a gray coloured RTV so it looks neater if any small smears ooze out. The tube had a variable speed setting too which was very easy to use. Get a nice fat even bead on top between the 2 clam shells you do not want a vacuum leak.

 

1. Those piece just stay put, they only go one way. You can't install those by mistake.

2. They just pry off. It's held by silicone or something similar. Just pry out.

 

Thank you, gentlemen; above instructions printed out, and that will be this morning's project.

 

Forgot to ask one other thing. There's a light-colored rubber gasket, BTW, that goes around the clam shells. Is it OK to reuse that gasket, or would a fat bead of RTV be a better idea if I'm understanding this post correctly?

1999 S430 Restoration project

Hi All,It was about 18 months ago that I bought a 1999 S430 which had been sitting un-used for nearly 10 years. Fast forward to now and it has been subject to serious welding and body restoration which is complete and the car was returned to the road with a fresh MOT certificate just a couple...

www.benzworld.org

 

I believe that gasket is actually machine applied RTV! And it is not available new either so don't re-use it. Instead apply a nice fat bead of RTV in the groove and it will definitely seal then. Don't forget to also seal the "fins" too on the inner sections VS the clam shells. This was tricky and I had to work fast before the RTV set up.

 

Also meant to say my flap mechanism really benefitted from oiling. The machine shop had ultrasonic cleaned it perhaps that dried it out. But applying high quality synthetic bike chain oil (fantastic stuff and in a handy little applicator tube with this nozzle) really freed it up and made it operate very nicely. I also used a Mittyvac type vacuum test tool to test the function of the flaps both before assembling the manifold clam shells and also after and prior to throttle body going on. That way I know all is good and moving freely without snagging.

I think there may have been an issue there before on my S430. The flaps were sticky and jamming with the thick carbon when I took it apart at the start. There were a couple of occasions where the car hardly pulled up hills and lost power. I do wonder was that the issue that the flaps were hanging up and the vacuum actuator wasn't strong enough to overcome the stiction

In any case all is clean and moving beautifuly in mine now

 

Thanks, JC220. Will do that. Indeed, I had noticed that there was some clear RTV on some other, thinner edges of the clam shells, yes. I'll be sure to do those as well, as well as oiling the flap mechanism.

 

OK, I've gotten that vacuum hose out of the intake manifold. It's certainly going to need replacement, as it's showing all sorts of cracks and such. A new hose will be getting built, but I'm going to see if I can cut off and reuse the "thicker" part, the part that butts up against the intake manifold's inner wall, as part of the rebuild. The reason for that is this particular part, being protected from the elements, looks to still be in very good shape.

We think that a vacuum hose tubing connector, of the appropriate size, should do the trick. If I can find something that works, I'll take pics and share them.

 

Didn't have my cell phone during the rebuild...darn it...so no pics for now. But I can tell you that it's a plastic, barbed tubing coupler, one side a bit larger than the other. The small size goes into the "thicker" part due to the small hole in that part of the original tube assembly. The thicker part goes into the fuel hose that I bought to replace the worn and cracking, about 25-30 cm long, "outside" section of the factory tube. It's a good, tight fit and should work well. We'll find out when we eventually fire up the engine.

If that goes well, then I'll rebuild the other intake manifold (remember, I've got two engines here, the bad one and the good--replacement--engine). That will probably be a couple of months from now, since I'm putting the entire engine bay back together.

 

To JC220, reference the brass air line fitting you used to the intake manifold for brake vacuum. Does it just screw on to the intake or did you thread the pipe housing while the manifold was off. Is there a part number for the brass fitting ( or name ), any details on it would be welcome.
My 85 year old hands are having a time with this.

 

Hi

Ref that fitting It was what I could get at a local parts store. I believe it was intended as an air line fitting for tractors or similar.

I did have to use a die grinder to open up the manifold hole a little and then self thread / force the new brass fitting in with some thread lock too. So yes I fitted that when the manifold was apart.

 

Dave hasn't been around in a long time, so that document is probably not available at this point, sadly.

 

New update for those in need. https://a.co/d/c1lHihW Fits almost perfectly, add a good sealing washer from the inside and boom new life to an old intake 😅

 

New update for those in need. E-outstanding Straight Barbed Connector 2PCS 1/4Inch ID Hose Barb Bulkheads Hex Union Brass Barbed Fitting Connectors with Flat Washer: Amazon.com: Industrial & Scientific Fits almost perfectly, add a good sealing washer from the inside and boom new life to an old intake 😅

This is the fix for the vacuum reservoir connection at the front of the intake? Is it effective?