96 E300D surging/missing after filter replacment
 

I've got a 96 E300D with 258k on it. In the course of normal maintenance, I ran a pint of Diesel purge through the system, then replaced the pre and main filters. After restarting, I ran it for 20 minutes and then shut it down.
This morning, on the way to work, at 55-60mph, the engine starting cutting out/surging. I could counter this by hard acceleration or letting my foot of the pedal completely. It did this at just after coming off cold and the rest of the way (16 miles) to work. The vehicle idles perfectly and has no leaks. What should I look for? I did notice that when it was cutting out, I got a bit of white smoke out the tail pipe.
Previously to this, the vehicle ran fine on the highway.
Thanks
jeff

Read more: http://mbworld.org/forums/e-class-w210/517672-96-e300d-surging-after-filter-replacement.html#ixzz2iNTfzVXm

[QUOTE=jfulford;3226668]I've got a 96 E300D with 258k on it. In the course of normal maintenance, I ran a pint of Diesel purge through the system, then replaced the pre and main filters. After restarting, I ran it for 20 minutes and then shut it down.
This morning, on the way to work, at 55-60mph, the engine starting cutting out/surging. I could counter this by hard acceleration or letting my foot of the pedal completely. It did this at just after coming off cold and the rest of the way (16 miles) to work. The vehicle idles perfectly and has no leaks. What should I look for? I did notice that when it was cutting out, I got a bit of white smoke out the tail pipe.
Previously to this, the vehicle ran fine on the highway.
Thanks
jeff


I know from reading other posts, that sometimes the pre-filter "o" ring may be damaged or missing which can cause a host of problems.

96 E300D surging
 

Yep, ran into exactly that earlier. Didn't notice that it didn't come with the .50c oring. Took the one off the old pre-filter and got that fixed.
jeff

Thanks for the replies! Checked for air bubbles: none that I can find.

I tried the EGR mod I've read about in the forums: Block off exhaust port, full galvanized gasket for egr valve, small filter on end of EGR tube. After finishing this mod, I have not had any problems(for the first time in quite a while.

This one has caught out many, including myself.

Didn't leak until engine was off and then poured out with pressure. Diesel all over my freshly installed serpentine belt:eek:

My suggestion is to replace that used O-ring you used with a new one. Used O-rings don't fare very well. It's certainly easy enough to do. Rule of thumb is that anytime you mess with the fuel filter, you replace the O-ring.

Pre filter 0ring
 

I generally replace anything along that line. I just didn't have one available at the time. I will replace it, though.
Thanks
jeff

I need to do this mod, my car is still doing the same thing. Are there any tips you can offer that's not covered in the forums already?

Thanks,

96 Surging
 

Not many, just a couple of specific to my situation: I used a copper 3/4" pipe plug to plug the exhaust port(removable). I didn't cut anything. I used 3/4" heater host to insert into the metal egr tube; got the small breather from Auto zone. had to heat the end of the 3/4" hose to get it over the metal portion of the breather. Clamped it. An, of course, used the original gasket to create a "solid" gasket out of galvanized roof edging.

jeff

Thanks. Two more quick questions - where does the solid gasket go? The EGR still opens to let fresh air in thru the breather filter, right? Otherwise the check engine will come on. Also - does the EGR tube come off by prying up the little "ears" at the bottom which hold it into the exhaust? Just checking.

96 E300D surging
 

My EGR tube just came off when I removed the clamp. Yep, fresh air through the now disconnected EGR tube and I modified a freeze plug AND a piece of galavanized steel as a block for the exhaust, reusing the original clamp.
jf

UPDATE on 96 E300D surging
 

UPDATE
It is almost completely confirmed that, if I PLUG in the block heater 2-4 hours before I Leave for work in the morning, I DO NOT get the surging or the smoke!
I still haven't removed the crossover tube to clean the resonance valve, but that is next on my list. I still don't have a clue as to what might be kicking in around 60C to cause the pinging and smoke.
jf





Read more: 96 E300D surging after filter replacement - MBWorld.org Forums[/QUOTE]

Testing EGR
 

The '96 E300D (W210, OM606NA) is not "smart" enough to know that EGR has been blocked for testing purposes only. It will (mine will) not set a code unless the electrical connection at the top of the EGR valve (plug w/3 wires) is removed. Caveat: I have a very early '96 (s/n about 5000); it's possible that later in the 1996 production year Mercedes added more electronics. YMMV.

I blocked both the intake and the outlet of the EGR valve and left everything else alone. It looks perfectly stock but does nothing so the air intake pipes now stay clean.

BTW, with EGR temporarily blocked for testing purposes only, the "throttle" flap just in front of the EGR valve can also be removed. Its purpose is only to help suck more dirty exhaust through the EGR valve into the engine. Remove two screws and the flap can be pulled out.

Jeremy

http://i323.photobucket.com/albums/n...D/EGR_7806.jpg

96 Surging
 

Jeremy5848

I've done what you have described: Blocked port, solid gasket on EGR, tube with small Air breather on end. I haven't removed the flap yet.
I took off the crossover tube yesterday. I had previously clean out the major parts of it. It wasn't that bad yet. I'm getting a vacuum tester to check the resonance valve.

Thanks for the great pic!
jeff

Was going thru some old threads saved on my computer, and realized i forgot to close this one out:

I blocked off the EGR tube on the exhaust end, and put a small auto parts store air filter on the EGR intake last November. My mileage went up from 27 to about 30 pretty much on the first fill-up after that. The surging went away.

Interestingly, the CEL (P0200 I think) came back on a week later. After a few days it went out. Two weeks later, it came back on again. I cleared it, and it stayed off. It's like the EGR or something was recovering after years of breathing in dirty exhaust. I suspect the cause was something in the EGR that got too dirty to function properly, and the clean air brought it back.

Thanks to all who gave advice!