PeachParts Mercedes-Benz Forum - View Single Post

2.5Turbo · #3 11-29-2007, 10:21 PM

Yes, the wastegate is vacuum operated on the 90-93 300D. Without it connected, the wastegate is held open and you'll get no boost and 18 second 0-60. For a test, hook up straight vacuum to the wastegate and see what you're performance is like. Try not to romp on it too hard to avoid overboosting. On the 90 the line from the wastegate actuator goes to a transducer that is mounted under the air cleaner. All this must be in place for the turbo to produce boost. Everything else also must be there and working (EGR, butterfly flap valve, airflow meter, rack sensor, crank sensor, temp sensor, etc) for the computer to not throw a code and cut boost. When I first got my car from my grandparents, it wasn't producing boost and I thought it was just supposed to be that slow for about 8k miles until I did some research and found out it wasn't. That's when I found that the wastegate transducer was bad.

On the oil problem, I'm not sure...could be a bad oil fitting gasket on the turbo.

The ticking is probably either a bad hydraulic lifter or a dripping injector. To test, loosen the nut holding the fuel line to the injector. Do this for each cylinder, one at a time and note if the tick goes away for any of them. If it does, that injector needs service. If none of them stop the ticking, then it's probably a lifter that needs replacement.