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QB93Z · 04-13-2010

GC, I am not sure if the Code 61 is related but here is what I observed on a 1994.

There is a pressure switch that monitors Secondary Vacuum and turns OFF the Secondaries if they have been commanded ON and the Secondary Vacuum drops too low to hold the secondaries open.

During acceleration, the Secondary system would cycle on and off. I had a scanner connected to the car during operation. What was happening was that a bad check valve between the secondaries and the other vacuum uses allowed vacuum "loss" when manifold air pressure went up (throttle valves wide open). The secondary vacuum pressure switch would sense rising pressure (loss of vacuum) and would shut off the secondaries. I believe that a code occurs from that event.

Jim

04-13-2010	#7
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	Re: Intermittent Code 61 Ideas GC, I am not sure if the Code 61 is related but here is what I observed on a 1994. There is a pressure switch that monitors Secondary Vacuum and turns OFF the Secondaries if they have been commanded ON and the Secondary Vacuum drops too low to hold the secondaries open. During acceleration, the Secondary system would cycle on and off. I had a scanner connected to the car during operation. What was happening was that a bad check valve between the secondaries and the other vacuum uses allowed vacuum "loss" when manifold air pressure went up (throttle valves wide open). The secondary vacuum pressure switch would sense rising pressure (loss of vacuum) and would shut off the secondaries. I believe that a code occurs from that event. Jim