My 1991 2.5 turbo diesel has 140k mi.
Until about 2 months ago, the car
accelerated briskly from 2200 rpm when
the turbo kicked in. In the last 2
months, the car often shows no increase
in power at 2200 rpm, and very low power
until approximately 3700 rpm. The fuel
injectors have not been replaced in the
last 70k mi and are probably original
to the car. In the last 6 months it has idled rough to very rough. Fuel filter
changes and Redline fuel treatment
have helped greatly and the primary
fuel filter now runs clear. Idle is
still somewhat rough at times.
I suspect the injectors are the
problem but would appreciate any
assistance in diagnosing the problem.

Darrell

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Doubt if injectors are causing boost problem. Start with timing chain inspection & injection pump timing check. There are 2 TRANSDUCERS for boost & air flap controls that can also cause boost problems. Several bulletins & modifications to these parts.

To add to DOC, I have seen where the plastic line that carries boost to the Pressure Sensor will crack or blow off. When this happens the computer will limp.

Have it checked.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

from the intake there is a hose that goes to a silinoid on the driver side fire wall, that then goes to the injection pump. I replaced mine for 26 dolloars and cleaned the hoses insides, and my problem with boost went away. and on the back of the pump near the oil can is a double bolt that has a spring loaded thing that smooths out idle, rplaced mine and my car runs like new with 240,000 miles on it.

Thank you all for the info. Chain
inspection and specs are not
covered by the service CD. Are
there specs or is any problem
obvious due to slack in the chain
beyond the tensioner's reach?

I inspected the hose and sensor on
the intake and all appear in good
shape. I did find diesel fuel
(not oil) leaking from the
inspection plate on the bottom of
the fuel injection pump. Could
this be related?

Are there test procedures buried in
the CD regarding the transducers
and solenoid?