84 GTI. I just installed a new exhaust and a g grind cam. Adjusted the valves to spec and got the car running decent enough that I feel comfortable driving it and decided to fine tune the fuel system again, as that is the last step before thrashing it in some mountains. When I put my multimeter on the test port, all I can get it to read is 67%. When I swap leads(hoping to see 33%), it still reads 67%. I have unplugged everything(hot and cold) and seen absolutely no change of the test port reading.
From what I have read and learned over the course of making CIS lambda work initially, the only time it should be at 65%+-2% is when the WOT switch is initiated. My thought is that the wire from the ecu to the WOT switch may be grounding out before it reaches the switch, as it is on its own circuit. Or maybe even internally in the ECU? I dont think it makes sense for the O2 sensor to be causing this but im at a loss for the moment and am open to suggestion. Has anyone else had this issue and resolved it? Thanks in advance.