1999 E300 turbodiesel loss of power!
 

Just the other day I noticed a huge drop in power in my Turbodiesel. I travel a route daily that includes climbing a steep hill and I am able to reach 65mph by the time I get to the top but now I am lucky to get up to 50mph. As a test I took my 1995 non turbo on the same route and 50 mph was the best I could get by the time I reached the top of the hill. It seems like the turbo in the '99 is not working at all. I did remove the vacuum hose going to the EGR on the'99 and plugged it about a month ago and it did not effect performance so i'm not sure if that may have anything to do with the loss of power I am experiencing now?

It may have thrown a code - this does remind me of a turbo engine that has sprung a leak somewhere on the intake plumbing. good luck

One of the recurring problems on the '98 (and I think the '99, also) is that the stop light switch goes bad. When that happens, you lose the turbo charger and usually the cruise control. When mine went bad, I lost the turbo and cruise control only intermittently -- it worked for a while and then stopped working while I was driving. I think my stop lights continued to function.

It's a $25 part from the dealer and is near the brake pedal. Check it. Also, check whether your cruise control and stop lights are working.

Sounds like it is in limp mode. Is ck engine message on? Look closely on the drivers side in engine compartment and you will see a pressure transducer mounted on the engine side of the "divider" close to the brake master cylinder. Follow the black rubber hose coming off of it to the intake manifold and make sure it has not blown off. If that is not it you will want to check for leaks between the turbo discharge and the intake manifold.

If you just unhooked the EGR actuator and plugged the line then you're probably in limp mode. The computer checks the operation of the EGR and if it does not detect the change in operation when the EGR valve cycles then it will set a P0400 and put you in limp mode.

Search on this forum for OM606.962 EGR bypass, you have to add a diode and resistor to the sensing line going to the ECU to fool the system.

Generally if the stop switch goes bad it fails in the state where it thinks you are pushing the brake. Note the brake switch on these cars has 2 sets of contacts. One set actuates the brake lights and the other goes to the ECU. The brake lights can function normally but the ECU signal may be stuck.

When the brake input is set on the ECU it prohibits acceleration above idle. This is a safety, no doubt inspired by the "runaway Audi 5000" that was still fresh in the engineer's minds back in the early 90s when they started designing the W210.

Also check the vacuum hose from the wastegate on the bottom of the turbo. They've blown loose in the past and caused low boost issues. I just replaced the wastegate on one of my e300s because a diaphragm had gone bad internally.

You are correct, I get a P0400 and engine performs fine for about a week or so, then power drops. If I erase the code I am good to go for another week or so before power drops again.
I wish someone provided a simple kit with the proper diode and resistor you mentioned that could be spliced into place by someone not too smart like me.

1999 E300 turbodiesel loss of power!
 

Does anyone know the part numbers for the wastegate and wastegate actuator? I have the part number for the whole turbo but I'm not sure if it comes with a new wastegate or actuator.
Thank you.