You have an 85. All 85's have an ARV on the turbo. The ARV is an emissions device used on these cars to increase the amount of EGR. This limits boost until about 3000 RPM.

Do a search on ARV in this forum to figure out how to deal with it.

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green 85 300SD 200K miles "Das Schlepper Frog" With a OM603 TBO360 turbo ( To be intercooled someday )( Kalifornistani emissons )
white 79 300SD 200K'ish miles "Farfegnugen" (RIP - cracked crank)
desert storm primer 63 T-bird "The Undead" (long term hibernation)

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