92 350SDL loss of power!?
 

Ok guys, I have a 350sdl here and its driving me nuts! The car has 180k miles, with a new MB engine assy at 132k. The car always ran great, gave good fuel mileage, and was fun to drive. Now thw issue; in the last year or so, we have noticed that it seems to be losing power and wont pull above 3200rpm. I know about the older cars and the alda soot problem, but this car does not seem to have the alda, as it looks like it has a ecu control for the enrichment under boost. I assume there must be a sensor somewhere that sees this, but I am lost!

Any help would greatly appreciated!.........JM

have you
 

checked the crossover for tar?

they will gum up pretty bad if the egr is still attached. and if the air is restricted this way they will idle and run fine at lower rpm but be gutless when the rpm is higher.

tom w

Yes we checked all the ovious stuff, and found a gummed up line at the manifold, but it still seems not a perky as it was. Any more ideas?.....JM

fuel filters?

filters
 

yes the filters have been replaced, along with the tank strainer

What body style is a 92 350SDL?

I'm pretty sure there is an ALDA on the IP. If 602s used an ALDA through 93 then 603 must have used it in 92. Figure out how boost translates to fuel enrichment and investigate that circuit. There has to be boost sensor or hard plastic line attached to the intake manifold. In fact there's probably one of each.

To further Tom's point, is this a model that cuts boost if the EGR is disabled? Has anyone touched the EGR system? Did a vacuum hose come off?

Next is a mechanical inspection of the turbo - axial and lateral shaft play, wastegate actuator and flap, etc.

Sixto