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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by hasaramat View Post
I have a 1989 turbo and it runs smooth and comes on boost just fine then at about 5000 rpm it is like someone flips a switch and it falls on its face. I almost hit my head on the steering wheel. When it falls I also get a puff of blue smoke on deceleration. My first thought was a bad rev limiting rotor but it has a standard rotor. The car does not quite it just comes off boost real fast. Any ideas?
By your description it sounds like the classic "face in dash" syndrome indicative of your overboost circuits kicking in and shutting off the fuel pumps. Could be your overboost sensor switch has aged to the point where it's tripping too soon under normal boost, or your wastegate isn't opening correctly and you are overboosting. What does your boost gauge say when this happens?

If it's just a bad OB sensor, simply replace it. Brand new, they shouldn't cut power to the pumps until you reach something like 1.2-1.4 bar of boost.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 04-18-2014, 05:27 AM
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