Since this past winter, my 1985 300D has had several problems:

1) 0-60 time is over 20 seconds, when it used to be 14. Low-end torque is good, but the engine totally loses power (the car even slows down) over 3,000rpm.
2) Engine doesn't shut off (must be shut off manually)
3) Gear shifts feel like low-speed collisions. Not even 1st to 2nd with an open throttle, which is what I espect. ALL upshifts and downshifts, even on light throttle, feel really harsh until I'm moving faster than 60mph.

I understand that numbers 2 and 3 can both be a result of vacuum problems (which I would believe, because my power locks don't work all that well), but #1 has me baffled. I've been told that it could be the ALDA, but I don't want to mess with adjusting the screw on top until I find out WHY it would suddenly need adjustment, after it was working GREAT in the fall and continued to be driven all winter.

Please help, I just want to know WHY the ALDA would have come "out of adjustment", and how I could go about testing the vacuum lines. I know nothing about vacuum systems, but I fear that if I don't get it resolved soon I might be damaging my transmission and drivetrain shifting the way it is.

One more bizarre little note: Standing outside of my car while it's running, I hear a light "clink" sound (like two small wrenches banging together) about every 30 seconds or so. This scares me...

PLEASE HELP, ANYBODY!!! I want to keep the Blue Beast on the road at least until I'm out of college!

Jerrold Adler
broke teenager
1985 300d
231,600 miles.

Hello broke teenager! I'm a broke adult! TXBill speaks truth. Vacuum is the key to alot of these cars functions. Search this forum and you will find alot of great info. I personally don't own a Mighty-vac but I can usually find problems by searching with my eyes. Replace rubber vacuum lines as a hobby! All vacuum problems are easy to fix, just hard to find. A couple of clues...the 3/2 way valve on to of the engine controls the tranny shifting. About $72.00 for the part. I changed mine and it smoothed right out. The trunk lock and gas cap lock are the most likely failures in the central locking system. You can check them by hand. Unhook the hoses and if the element is good, plug one hole and you will not be able to move the cylinder back and forth. Try plugging both holes. If it's bad you will know because you will be able to hear air sucking into it while you pull the work cylinder out or push it in.

__________________
1982 300D Turbo "Helga"
380,000 miles

Use the search function for the words "vaccuum" or "hard shifting" or "modulator" and you will be busy for months reading it all !

Welcome to the forum, we will help you get back on the road smoothly! It sounds like you have a simple vaccuum leak.
One thing to check is the modulator, see if the vaccuum line is still connected. If it is, pull the cap off of it and replace the O-ring. Cheap enough,

__________________
Ed
1981 300CD (Benzina)
1968 250 S (Gina) 266,000 miles!
1983 Alfa Romeo GTV6 (Guido)
1976 Jaguar XJS-saved a V-12 from the chevy curse, what a great engine!
1988 Cadillac Eldorado (better car than you might think!)
1988 Yamaha Venture (better than a Wing!)
1977 Suzuki GS750B
1976 Yamaha XS 650 (sold)
1991 Suzuki GSX1100G (Shafty Gixser)
1981 Yamaha VX920RH (Euro "Virago")
Solex Moped
1975 Dodge P/U camper


"Time spent in the company of a cat, a beer, and this forum, is not time wasted!"

Hi there,

i've had the same shifting problem in my w124 300d turbo, it was a vacuum line which has come off, it goes from the transmission to the right-side of the engine (when you face the engine looking under the hood) to a little pump. This pump makes the right decisions when hard or soft shifts need to be made (low rpm/high rpm shifting)... or... the little pump has to be replaced... not so very likely though it can happen..

about the acceleration: this is also vacuum related, can't tell you exactly which vacuum line it is by heart but it is somewhere near the diesel pump, more to the back of the car..

the shut-off is also vacuum controlled, vacuum line running to the top of the diesel pump...



all problems here are vacuum related but are all on seperate lines, so I think you have one major leak at the main vacuum pump or the lines coming out of there.

Good luck and let us know of your progress!

Jerrold:

You have either a vaccum leak or a bad vaccum pump.

A MitiVac will be a great help since it has a gauge on it -- about $30 at your local autoparts store.

Since you have problems with locks, shutoff, and shifting, I'd guess a major leak or a bad vacuum pump (which would also account for the click).

You can check for pump function by measuring vacuum at the main line from the pump (it goes to the vacuum booster for the brakes) -- you should have at least 12" vacuum at idle, probably more. If you don't, look for leaks. If you have no leaks, the vacuum pump is shot. Not a huge deal fix, specially on a W123 or W126.

Your performace problem is most likely plugged fuel filters -- do you get any smoke at full throttle? If not, you have fuel deliver problems.

The boost line can also be plugged at the manifold (common), or one of the rubber connectors may be bad, letting all the pressure leak off. You could also have a bad overboost switchover valve, but I'd check fuel filters first. They usually need replacement every 30,000 miles, but if you have less than pristine fuel, will get plugged faster. Makes a huge difference.

Also check for fuel leaks -- you will need to park the car nose down on a steep slope (the fuel usually siphons back into the tank otherwise) -- a leaking suction line will let air in instead of fuel, greatly reducing performance. So will a plugged tank screen from algae or really dirty fuel -- probably not the case for you, since algae is a warm weather problem.

Hope this helps -- let us know if you are still lost!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I went back and bought a coil of slightly smaller-gauge vacuum lines, and it turned out that the only problem I had been having just now was that I was using vacuum lines that were too big. This smaller tubing had to REALLY be forced on, but it seals tight and I'm shifting smoothly enough.

Now... to find the OTHER vacuum problems in my car...

My two center air vents on my dash don't work. I understand that they're controlled by a vacuum actuator much like the ones that don't lock or unlock my doors an hour after my car has been shut off. Also, my car often doesn't stop running until a minute after I turn the car off (sometimes shorter, sometimes longer) which is really annoying.

I have been told that I have a vacuum leak SOMEWHERE that is causing all of these problems, but I have no idea where to start looking. I have checked all of the door actuators, and they appear to be functioning (with a hole plugged, they're impossible to work). The fuel tank door lock has been bypassed by a previous owner (the bypass is sealed up tight... that's not a big priority) and the trunk actuator is working fine. I have even tried to manually move the one inside the center console that opens the foot vents in the front, and although those vents DON'T work when my car is running, I cannot make them open manually.

So in a nutshell, I have a leak SOMEWHERE.
It is not any of the 4 doors, or the fuel door, or the trunk, or the foot-vent actuator. I have replaced all of the little rubber connectors that I can reach under the hood. (You know, any that appear to be coming out of one of the little plastic round things on the driver's side under the hood).

Where could the leaks be? Can I get a vacuum diagram somewhere?

And don't even get me STARTED on the water leaks every time it rains. But while we're on my topic, what could make all 4 floormats (front left/right, rear left/right) VERY wet when it rains hard? I have to dry them out on my lawn, and leave my car out with the windows open on a nice day to get rid of the mildew smell.

Right now it's parked under the overhang of my barn, but I'd love to find the source of the leak, so my car doesn't have to be afraid of the rain. By observation, the only way that a massive amount of water could get into both sides of my car is if it found a way past the firewall... such as getting into those two air intakes on top of my hood (right at the bottom of the windshield) and not draining properly. Could this be the case? And if so, how can I remove the black plastic screens (rather delicate) so that I can clear out blocked drains? I really hope there's some easy, obvious way to get in there.

Sorry for such a long post, but I've got a few issues I'd love to clear up with my car. Truthfully, the water leak is MUCH more troubling than the goofy vacuum system (that I can life with).

Thank you SO much,
Jerrold
1985 300D
232,000 miles
Vacuum Issues
Leaks Lots Of Water
Drippy-Looking Paint
Rust In Wheel-Wells

...And yet I love my Benz!!!!

You've got drains located near where the fenders meet the firewall, kinda hard to spot but if you clean out all the accumulated crud you'll see them. The drains likely need to be cleaned out. Also, if you have a sun roof there are drains at the corners - if your headliner is getting wet they are likely plugged too. Check the windshield and rear glass rubber, if dry rotted, guess what, another source of water.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Jerrold:

You will have to get a MitiVac to fix the vacuum, not really possible without it. Fairly easy to troubleshoot the climate control and door lock with -- the vacuum supply for the climate control is the green plastic line up by the brake booster, the lock supply line is yellow. If you can pump the vaccum down on either one and it holds with the Mitivac, the problem is supply. If you cannot get a solid vacuum with the MitiVac, you have leaks.

You may also have a major leak somewhere around the booster or other vacuum operated stuff -- if just found out last night that the EGR and air recirc swithover valves on my 87 300D were bad -- no center vents with the AC on. I have pugged the hoses pending replacement or repair of vacuum lines.

The water is from bad window gaskets or one of the other causes listed. If it is the window gaskets, get them replaced right away -- front and rear windows both have a large heavy rubber "seal" -- this is shrunk and lets water in at the top. The water then travels around the edge of the glass and out the bottom inside, and hence down below the package shelf and dashboard to the floor. You will have rain marks over the wheel wells in the trunk, too.

There are also four sunroof drains (the panel doesn't seal, there is a tray to catch the water) -- if these are plugged, water comes out from the top corners in front, soaking the floor.

There is also a foam tube connecting the AC water drain to the exterior -- dead center above the tranny under the radio. If this is gone (and if it hasn't been replaced, it is), any water that gets into the climate control and/or AC condensate will run out from under the console.

Finally, there are drains at the front corners, under the air intake grilles. These can be plugged, and if they are, water will spill over into the back of the dash area. They can also be rusted out , requiring sheetmetal repairs.

Good luck!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thanks for the tip (plugged fuel filters) that solved my "300d Turbo with NO POWER AT ALL" problem. After getting the wrong fuel filter at National Auto (evidently they gave me a different 1985 300d fuel filter that was too tall for my engine) then getting the wrong one at Pep Boys (they gave me one with a bolt hole in the top that was about a millimeter too small for my 300d, they finally looked up the filter for a 300CD and it fit GREAT into my car. Standing in the rain in the parking lot with my hands greasy and reeking of diesel, I threw that last one in, primed the fuel system with that little built-in primer pump and OFF I WENT!

On the way to the Pep Boys, I was barely able to maintain 70mph on the highway in top gear with my foot to the floor. On the way home, I stomped the accelerator, and eventually decided to back off when I passed 90mph with no end in sight. Funny how something as simple as a clogged fuel filter can make you think there's something morbidly wrong with your car. And here I thought I had ruined the compression from starting the engine cold, well below freezing, every morning at 6:30 all winter long (without a block warmer... my heating elements are dead).

Speaking of, the aforementioned probably isn't the best idea... but she's still running strong. Otherwise, I treat her well.

Anyway, my little light-blue tank is running like the turbo-diesel rocket she's supposed to be, thanks to everyone on the list who responded.

Happy motoring to all! (I'm having a blast!)

-a VERY happy Jerrold.