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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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Quote:
Originally Posted by spaceman1 View Post
85 930-Hey folks recently my boost gauge needle has been jumping all over the place. I changed the pressure sending unit and pressure switch but still no luck on the erroneous readings. Any ideas thanks?????
I'm not aware of any pressure switch associated with the gauge function....just the pressure sending unit that you apparently changed out.

If you have a bad ground to the sending unit, or a bad connection for the wire that leads up to the gauge itself, you may see the gauge pegging to max boost if the ground or connection is disconnected, or conversely will see the gauge resting at zero if all connections/grounds are good. Perhaps you have a broken wire - the brown wire (if I recall the color correctly) that's connected to the sending unit. With the ignition on, try moving that wire near it's connecting point to see if the gauge bounces around.

Finally, is the sender mounted in it's stock location on the intake manifold (actually, the boost recirculation manifold) or is it mounted to the intercooler? If to the intercooler, you may need to run a separate ground.
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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 05-15-2013, 02:51 PM
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