I am pretty sure my solenoid is broken/defective and is dumping the pressure signal to the ALDA. Warm weather begets tinkering for me, so after checking and rechecking, I just bypassed the overboost (OB) solenoid on the 300TD and ran the intake pressure direct to the ALDA. I've been hesitant to do this for safety reasons in the past. Yay and yikes the wagon behaves more like my E300!

Does the OB switch trigger the OB protection solenoid? How do I test the OB switch either on or off the engine? What is effected, soot/fuel/other, if my OB protection circuit(switch/solenoid) has been in 'dump' mode for quite awhile(years)

The 300TD has been a dog since I got it (2/2014) regardless of some of the things I have checked/done after researching here. The car runs very well otherwise and I thought it was turbo related and beyond my abilities for now. Over the past year I have R&R'd-Cleaned IM, replaced return lines, diesel purges, cracked Inj. nuts to bleed air, checked boost(11-12 psi w/T in line to/before solenoid), cleaned fittings/lines on the OB circuit, replaced air/fuel filters...etc.

Therefore, I'm thinking the solenoid has been dumping pressure when energized.


PS:Its my kids car so it has been OK to me for it run like an NA...ya know nice n slow.

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Treetops
06 E320 CDI 127K Miles
87 300TD 231K Miles

99 E300 269K Miles-Sold