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WERK I WERK I is offline
Forced Induction Junkie
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Join Date: Jan 2003
Location: Wisconsin
Posts: 3,302
Originally Posted by 550SPYDER View Post
IS THIS RIGHT? Below are 2 pictures one is of the sensors that are connected to my Koklen intercooler. After I had a chance to trace the wires, THEY ARE BOTH CONNECTED TO THE COIL - is that right? There are no other wires connected to the intercooler.... For what it is worth, the wire that goes to the boost gage is connected to the side of the coil closest to the rear bumper and the wire that is connected to the pressure switch. Which I guess means that I am getting boost readings from somewhere else????
In a word, NO. Both wires feeding the pressure switch and the boost sensor should come off the engine wire harness. The boost sensor, is nothing more than a variable resistor, just like the oil pressure sensor. The boost gauge is nothing more than volt meter reading the varying voltage drop across the boost sensor.
The boost switch is just that. It is normally closed, which completes the ground circuit feeding the overboost relay. When the boost limit is reached the switch opens, breaking ground, causing the overboost relay to trip.

Both the switch and the sensor use chassis ground (which the frame of IC should be) as one part of the circuit. The two wires coming off the main harness is the other part of the circuit.
'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 01-24-2009, 09:31 AM
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