'89 760T - Checking the DC Voltage across the oxygen sensor lead while connected reads about .45 - .55 fluctuating -- approx. 2-3 times sec. I believe this dynamic reading is relatively ok. On the other hand, disconnected the sensor lead to the ECU. Measured at the lead towards oxygen sensor about .15 volts. Disconnected both vacuum hoses at throttle body to check for sensor's response to lean mixture. No change. Then disconnected hose at Turbo boost switch. Went from .15VDC to .08VDC in about 3 secs. Seems that this not ok. No response to TB hoses. And response to Turbo boost vacuum hose too slow.

When checking with the oxygen sensor lead disconnected what should the DC Volts measurement be -- before disconnecting a vacuum line? Is .15 too low? Is it indicitive of an existing vacuum leak? And perhaps is this why there was no change when the TB vacuum hoses were disconnected? Also, the Air filter housing unit does not completely seal -- broken clips. Would this have any affect on engine vacuum?

Thanks!


--
dnvolvo '89 765T - '91 245