TMAllison - I somewhat understand the flap by the egr - it controls the blending of exhaust gases and fresh air feeding the IM for emission purposes.
But, what exactly do the crossover and IM resonance flaps do? Do they work in conjuction with the egr blending flap or are they independent of it?

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1995 E300 Diesel
2002 GMC Duramax CC LB 4X4

No, they're all controlled independently. I don't quite understand the theory of why the 2 intake flaps work but I know they're for optimizing the engine's power band and maybe also idle quality. From my observation the one in the crossover pipe starts to move and restrict air flow around 3000 RPM. The one in the intake manifold opens just over 1000 RPM. The EGR flap opens around 2000 RPM at light throttle and closes with higher RPM's and/or full throttle.

One other thing I recently did with the flap in my crossover pipe is loosen the blade and re-adjust it, then lube it again. I also re-lubed the others. It seems to have helped some more. I still get the occasional ping but you really have to listen for it and it's much better than it used to be. I'm sure higher-cetane fuel would help further. The cetane additive I use can only do so much.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Diesel Addict - I read this post over at the ************** web site and I thought about your pinging problem. If you sift throug all the egr stuff, it comes down to the timing as the cause the pinging?

"Besides being an emission control device and lowering the percentage of Ntrogen oxides in the exhaust, the EGR valve has the effect of diluting the fuel/air mixture and causing somewhat lower combustion temperature inside the cylinders. Also, due to its diluting effect, the pump injection timing is set slightly ahead to compensate. Same goes for gasoline engines. As a matter of fact, when an EGR valve fails closed on a gasoline engine (as due to bad vacuum diaphragm), the engine will start pinging when run on regular gas. This is due to ignition timing advanced further to compensate for the EGR effect. The solution then is to replace the EGR. A temporary fix is to run premium fuel or retard the ignition timing several degrees. Using the same logic, I would think that retarding the diesel injection pump timing by several degrees would be the correct compensation for a non-functioning EGR. You generally do not hear "pinging" or preignition in a diesel engine, but it could possibly occur."

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1995 E300 Diesel
2002 GMC Duramax CC LB 4X4

I believe pinging in a diesel is always related to late combustion, where too much fuel is injected before it has a chance to ignite, and then you end up with too much fuel igniting all at once. My EGR appears to be working correctly and my timing appeared correct as well last time I checked it. I wonder then if delaying the timing could be useful in compensating for wear & tear, but then again the engine seems to run too good to have much wear. Hardly any oil consumption either.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

It seems that I have finally killed the pinging. At least I haven't heard it for a few days now. What seems to have done it is another can of Diesel Purge, but this time it was AFTER the Bosio nozzle installation. Before the nozzle swap diesel purging only had a temporary effect, probably because the original nozzles weren't spraying so great. We'll see if this time it's fixed for good.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

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1995 E300 Diesel
2002 GMC Duramax CC LB 4X4

I also own a 96 e300 d, and the following information pertains to my model too.

This information was provided in another thread, and the owner had a 95 E300d
Here's how the resonance flaps work on my car;

The valve in the crossover pipe, I'll call X/O, and the valve in the manifold itself, I'll call 3/6.

The solenoid for the X/O valve is connected to the Yellow / Brown wire pair, and is the upper of the two solenoids when in the as installed position.

The solenoid for the 3/6 valve is connected to the Grey / Brown wire pair.

In the relaxed position with no vacuum, the X/O valve is closed - i.e. the crossover pipes remain independent for their full length.

With no vacuum, the 3/6 valve is closed, and the manifold behaves as an independent pair of 3 cylinder manifolds.

<2400 rpm 3/6 valve Closed, X/O valve Closed

>2400 rpm &
<3500 rpm 3/6 valve Closed, X/O valve Open

>3500 rpm 3/6 valve Open, X/O valve Open

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96 E300d

Oops I'm a little late to this thread, but just wanted to add that I have the Bosio nozzles in my 606 and they are great, runs nicely no issues. I pulled my injectors and took them, and the new nozzles to the local diesel injection shop. They balanced and pop-tested them.

I've also had Bosio nozzles in my TDI for about 100k miles now, pleased with those too, good power, no issues.

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'98 E300 turbodiesel

It's different on my '96. Like I said the 3/6 valve on mine opens as early as approx. 1000 RPM. But I think the X/O behavior is the same as I noticed that one opens much later, but I don't know exactly at what RPM.

Also interesting is my observation that yes, both valves are closed with the engine off, but if you unplug their electrical connections with the engine on, both valves open.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

I ordered six new nozzles for my 86 SDL. If I find a diesel shop to pop test and balance how do I know they Really did the work? New to MB and diesels. Shawn

Choose a shop you feel you can trust....? Or, watch while it is done.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Hope you got name brand nozzles... you may want to install them and break them in for a couple thousand miles before balancing, though.

I have nothing against breaking in new Injector Nozzles and then having them Pop Tested; but, no place I have ever worked (during 18 years) deemed this necessary for either new or rebuilt nozzles.

If I did decide to do this it would mean Pop Testing them when they were rebuilt and pulling them out severl K later and Pop Testing them again. Not just exchanging Spray Nozzles for a new one and putting them on the engine without Pop Testing.

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84 300D, 82 Volvo 244Gl Diesel

New nozzles often don't spray perfectly, they need some break-in time. Not always though. But after break-in, the pop pressures typically drop by 2-5 bar compared to new. I'd pop test before installing and write down the numbers, then run then for a few thousand miles, then remove and balance them.

If you balance to begin with, you may need to re-balance a few after break-in (or all of them, if you're trying to set to a specific pressure). Of course this is much easier if you have a pop tester in your garage (~$200 or so). Kinda tough if you're paying a shop to do the work.