85 300SD 231,000 - bought with 180,000 in Oct 2005 - used for communting from Tennessee to Maryland and back a few times each month. Just useless FYI!!

Problem is.. at low speeds taking off, it can hardly get out of it's own way especially with A/C - was going to give this to my son when he gets his license but i'm a little worried it is too slow and he'll have no power to get out of trouble if he pulls out in front of someone.

i hooked up a pressure gauge between the switchover valve and the line to the ALDA. when taking off i get 1-3 psi until about 2500 rpm when the pressure starts climbing. at about 3000 rpm i'm getting 7.5 psi. My 126 Service Manual CD tells me I should have more like 11-13 psi at 2000 rpm and around 6 psi at 1500 rpm. also hooked up pressure gauge so the switchover valve was bypassed (line from manifold was t'd with the line going to ALDA. same readings so it appears switchover valve is NOT at fault for limiting boost

i have 84 300SD that seems to have a lot more low end pickup AND you can hear the turbo whistle as you take off. i never hear the turbo on the 85

i get about 27 mpg on the highway going about 70 mph on my 10 hr drives

i've been working at replacing all the little rubber vacuum connectors, i've cleaned my line from the manifold to the switchover valve - it was never plugged up but cleaned it out anyway

both fuel filters were replaced in late December after performing diesel purge which resulted in NO perceptible performance enhancement. air filter replaced about 6 weeks ago.

i finally broke down and "molested" my ALDA. took the seal off and turned the screw counter clockwise 1/4 turn. made no discernable difference, turned it out 1/2 turn, made no difference other than started smoking on take off so i turned it back in to just a 1/4 turn

any comments? anything i should check to help figure this out?

R Martin
Chattanooga, TN
84 300SD
85 300SD