Turbo problem? - PeachParts Mercedes-Benz Forum

Gordo · #1 10-10-2006, 11:57 AM

My 85 300TD Turbo is prety slow. I have adjusted valve lash, checked timming chain strech (about 2 degrees), checked Inj timming (drip method about 24 degrees BTDC), the alda is maxed out with little or no smoke. I put a boost gauge on it and there was only 8psi, so a took the hose off the waste-gate. The boost went to 12psi. It seems like it should be more? I live at 8000ft above sea level and need the power in the mountains. Also I am only getting about 20mpg. Can anyone help?

rrgrassi · #2 10-10-2006, 12:15 PM

Have you cleaned you banjo bolts on the ALDA and the intake yet? How are the lines between the the ALDA and the intake? Have you checked your turbo switch over valve? Mine was frozen shut, and the PO bypassed it instead of replacing it.

Gordo · #3 10-10-2006, 12:29 PM

Banjo bolts and lines are all clear. By turbo swich over valve I assume you are talking about the relay looking thing in the middle of the line that goes from the intake to the alda. I bypassed that and there is no change in performance.

rrgrassi · #4 10-10-2006, 12:42 PM

Yes, that would be the relay thing, and you should be getting about 15 to 17 psi of boost IIRC. It is possible that the waste gate is not closing all the way, or a seal is leaking.

Also, when was the last time the air filter was checked/replaced. Just trying to run down the simple list first.

If all checks out, you will need to check your turbo as a next plan of action.

Gordo · #5 10-10-2006, 12:48 PM

Brand new air filter. All the pressure likes look good. The difference in boost from 8psi to 12psi with the wast gate hose off did not change the performance. Is this because I have a fuel problem? How do I check the turbo? Do I need to remove it from the car? Thanks for your help. IIRC?

rrgrassi · #6 10-10-2006, 12:59 PM

IIRC If I Remember Correctly.

I have not had messed with my turbo yet, as I have not had the need to, but I do need to change the U -Tube seals, so I'll be doing the spin test and the lateral play test by hand.

Engine needs to be turned off, and cold, or slightly warm. With the U-Tube off, spin the blade of the turbine and it should spin very feely. Then see if you can make the turbine move back and forth on it's axis. You do not want it to move laterally. If it does not spinn freely, or if you see broken or cracked fins, it is time for a rebuild or replacement.

If you do run the engine, with the U-Tube off, you run the high risk of having something sucked in, including your fingers. Turbo fins make nice slicers.