Anemic / Slow Acceleration Problem SOLVED!!! Cleaned Switchover Valve - WOW!
 

Anemic / slow acceleration problem solved!!!

You guys are great!

ALDA was definitely not getting boost. Cleaned Turbo Overboost Protection Relay / Switchover Valve ? - was all packed up with soot - had to use wire and lots of carb cleaner, but broke it loose, and YEEHHHHAAAA the old girl will do 100mph now, and thats with 302,000 on it! :D

This was one of the easiest fixes I have ever done that made such a huge improvement.

These cars are so much fun to play with.

Thank you all for all your help and suggestions.

I'll still do the valve adjustment and I have no idea when it was last done. I can't wait to see what it feels like then! :D

Thanks again all!

is it possible to have bypassed the switchover valve? there is a vacuum valve looking thing thats bolted to the heat shield against the firewall which my mechanic said he bypassed. I was wondering if this is the switchover valve?

Yeah, I'm not exactly clear on this "switchover valve" you're talking about either...

Got any pictures?

the "switchover valve" you are most likely referring to is the overboost protection relay.
it is there to prevent the alda adding fuel to the system in the event of excessive turbo boost. modify at your own risk.

You might consider disabling your egr so you there are no repeat performances of the above.

I believe it is just a bad choice of words the Switchover Valve I belive is the name of the on/off valve that allows the hot coolant to go to the hearter core or not. Also on the fire wall but on the passenger side near the intake manifold.

I apologize for using the incorrect terminology. Others on this board have referred to the Overboost Protection Relay as the Switchover Valve, so that is why I used the later term.

The device I removed and cleaned is indeed the Overboost Protection Relay.

Sorry for any confusion.:o

http://www.dieselgiant.com/mercedesaldaboostsystemservi.htm

Follow the hard plastic opaque colored line that goes from it to the the device on the firewall, behind the brake booster. This device is the Overboost Protection Relay (OPR). This device (and lines), if clogged will prevent proper boost from reaching the ALDA, which means your engine will not receive the proper amount of fuel relative to how much you are pushing the go pedal.

The OPR needs to be taken off, cleaned with carb cleaner and in my case, wire to reem out the soot. There is another hard plastic opaque colored line that goes from the OPR to the back of the intake manifold. Both of these lines need to be free from soot. Also, make sure the banjo bolt at the back of the intake manifold is free from soot as well.

Remove, clean, install and watch your frown turn upside down with "new power" from your diesel.

The difference was night and day.

That is the "monovalve."

switch/bolt clarrification
 

Just to clarify, you cleaned the actual OPR switch, or the banjo bolt and plastic as in the DG tutorial? I'm also hearing carb cleaner from you and brake cleaner from DG, do you think it matters?

I'm having a similar problem with my 85 300DT. I noticed, however, that it is mostly slow to accelerate from idle, and has some pep if it's at 30 or more mph, so this might not work for me. Going to give it a shot anyway.
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Cheers!

Same thing I'm experiencing, it seems to be better once the car warms up too. However today I looked at it and it looked like one of the injector return lines is leaking. I'm also thinking that the spin-on 10 micron filter is getting clogged since I'm running some soltron through the tank. If it is clogging, it would probably put extra pressure on the return lines. Good job with reporting back on the banjo bolt, that my next item as well...will report back!

still looking
 

thanks to all for the great info here,does my 87 300d have this banjo bolt set up

No banjo bolt, but there is a line you should check out. It's the hose coming off of the intake manifold, on the driver's side, that goes to a little switchover valve.

I cleaned the valve out with brake cleaner, soot shot out the other end..also used a wire to clear the opening that the line connects to on the manifold.

If yours is clogged, you're in for a surprise!

thanks dan,that hose and valve looked pretty clear,cleaner blew right thru it.but i did unscrew that sender right above the hose i think u were talkin about and that had some splooge on it.thanks again .