I have a 1992 W124 300D with the 2.5l turbo diesel engine. I have noticed that after 10-15 minutes of driving the car, the turbo fails to spool. After this time, I can no longer hear the turbo and there's a decrease in acceleration and power. If I turn off the car and turn it back on, the turbo works again for another 10 minutes or so. The car was just repaired because there wasn't sufficient vacuum pressure and the transmission wasn't shifting, the invoice states that the vacuum regulator and modulator were replaced.

I looked under the hood and noticed that a vacuum line from the intake sensor was unplugged (I'll include a photo)

I've searched quite a bit and I haven't really found anything documenting my issue.

I would appreciate your input, thanks!

On the left side of the intake manifold, find the large electrical sensor. This is the overboost sensor, directly below it you will find a hose connection. This is the alda boost sensor line. Make sure its connected, and that the fitting on the manifold is soot-free.

I cleaned the soot out of the fitting and the line and the issue still persists.

Mxfrank - could it be a bad switchover valve?

Get a length of the correctly sized rubber hose and bypass the switch. That will take that part out of the circuit. If nothing changes look at the hoses and connections going to the wastegate.

__________________
Jim

odds are it is probably vacuum related. Turbo waste gate is controlled by vacuum in these cars through a whole mess of tubes and fitting and valves on the turbo side of the engine compartment.

start there by looking for something obviously disconnected. if you want to bypass all those controls TEMPORARILY straight tube vacuum to the waste gate and go for a SHORT drive. You should feel the turbo in full effect with it like that.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

I'm going to start by carefully examining the vacuum lines for cracks or leaks.

A common mod to these cars is to replace the vacuum wastage actuator with a pressure wastage. There should be a few threads around detailing this.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

Lots of good suggestions and one not so good. It's vacuum related, and may be either a clogged alda switchover valve or a problem with the wastegate actuator plumbing. Try to find the problem before making wholesale changes to the vacuum system.

Most likely it is related to a failed/failing vacuum transducer (sometimes also called pressure converter valve). There are usually one for EGR valve, one for wastegate and one for intake flapper valve. They are sitting by the air filter box. Any one of these failing will cause EDS to misbehave. Common issue with OM602/603 motors.