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lucittm lucittm is offline
Manassas, VA
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Join Date: Apr 2007
Posts: 1,211
Lightbulb Myster Solved

I think I answered my own question. A few days ago I was really standing on it and the car shut down like it hit a brick wall when I got to about 6000 RPMs. I read in the PEC that the function of the boost pressure switch is to remove the ground from the fuel pumps if the switch detects an over boost condition.

I have extra springs in my waste gate, so I probably was over 1.1 bar. The shocker though, was the dramatic reduction in acceleration. It came on so fast I was literally thrown forward and both hands nearly came off the wheel. Foolishly, I tested it once more and it was the same as the first time.

I guess the PO had this experience and crossed the wires to prevent the switch from opening and removing the ground signal (it is normally closed). I would not think the wire to the pressure transmitter (for the OBC boost guage) would be enough of a ground, but I guess it is.

Too bad the boost pressure switch is not adjustable. I will leave the modification off the car, but what fun is 1.1+ bar of boost if you can't use it?

1991 964 Polar Silver Metallic Turbo Coupe
Old 07-06-2007, 07:56 PM
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