I have a 1985 300sd and the car acts like the fuel filter is stopped up, but I have changed the primary and secondary filters. My question is how do I troubleshoot this? How do I tell if the turbo is working? Does anyone know the best way to solve this problem? The car has been dependable until now. Help Please. Thanks Jack

I've heard it said before, to check the turbo for binding, make sure the engine is not running, take off the air cleaner and ducting to the turbo and gently try to turn the turbo intake turbine. If it wont turn or binds, you may have a bad bearing in your turbo.

Check to see if your air filter is dirty or if there are any obstructions in the airway through the filter.

Codifex
1981 240D ChinaBlue (found an engine - hope it's good)
1983 300DTurbo w/sunroof

When you say acts like the filter is stopped up, I'll assume you're having idle or accelerating difficulties, could you be more specific?
How long have you had the car, has the tank strainer been cleaned?

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83 SD

84 CD

First, tell us how it works at idle when you first start it up and then describe what happens when you start accelerating from dead stop. When I first bought my car I had a similar symptoms. Here are things that I would check first:

1) Make sure you have fresh fuel and not some left over Biodiesel experiment fuel in the tank - a diesel purge may be in order. This will isolate the fuel you have in the tank and allow you to run on pure fuel from the can. Could tell you something.

2) Check the banjo bolt on the back of the exhaust manifold - mine was clogged up with soot and oil. It must be squeeky clean as well as all of the plastic tubing going from the exhaust manifold to the overboost valve on the firewall and continuing to the ALDA on your IP. Also check all the lines in that path and make sure you have no leaks in them - if you do the ALDA will not get the right signals and you will be crawling until you hit 2000rpms and then the car will take off like a rocket... that's what's been happening to me in the past.

Check these first - go from there. I ended up adjusting ALDA after exhausting other possibilities.

Good luck - let us know,
James

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

The car runs fine idling. The power is lost during acceleration. I cannot climb a hill withought passing gear. I have had fiters to plug and this is the symptom. Where is the ALDA located? Thanks

Sounds like the problem may be somewhere between the banjo bolt and the ALDA - make sure you check all that - see my previous post. The ALDA is a square aluminum device mounted on your IP - it may have a black plastic cap on it (if untouched) or a nut with a flat-head screw in it (if compromised/adjusted).

Search ALDA for some photos of it - if need be.

Does the car eventually take off when you reach 2000rpms or so?!

See this post - it may be helpful: performance problems (85 300D turbo)

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

The ALDA has that black cap as mentioned.
There is a hard clear thick vac line coming from the back of the manifold. There is a bolt on the manifold, a banjo bolt. Make sure that banjo bolt and vac line are clear of gunk. Follow it over to a switchover valve, then to the ALDA.

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83 SD

84 CD