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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 IDGAF27 View Post
So, "going south" alternator can be a cause for jumping RPMs? Mines is pulsating 700 to 1500.
I think what we're talking about here is the tach moving eradically independent of the engine's true rpms. If your engine is truely fluctuating in rpm's, then it probably has nothing to do with the alternator. More likely vacuum/air leaks or fuel delivery fluctuations. Go through the complete tuneup sequence (check timing, check WUR control pressures) to first rule them out.

When the alternator goes, it starts producing an inconsistent voltage...and for voltage sensitive stuff like tachs and maybe digital WUR's, they will react really weird. That seems to be what most people see when alternators start to go. Never experienced it myself....yet.
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 03-21-2010, 10:36 AM
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