Hey guys trying to diagnose my issue. I've pulled my speedo sensor out and check it has a AC voltage when using a drill to spin it up. Which is does. Changes from -AC to +AC. I then check that it continuity comes and goes but not at the sensor, at the plug that connects to the cluster. ref (http://300zx.co.uk/tech/manual/manual/efec/179.gif <--- bottom of page) I get 0.000 resistance or a -ve or +ve value. it never goes open circuit. indication continuity coming and going. Is this to say the sensor is faulty? Even though I'm seeing a fluctuating AC voltage? Cluster "was told" was working so want to eliminate the wiring, sensor before returning the second hand cluster.
so you have verified the speed sensor is working by manually spinning it up? what exactly works and doesn't work on your cluster?
I have no speed and heavy steering. I have now confirmed no odometer clicking over, which my research tells me its sender. But yes I did manually remove the sensor and see a +ve and -ve changeing AC voltage.. BUT I'm not seeing the sensor's continuity coming and going as referred to in the FSM in the link
might be nice if both your tests showed the same result. presumably if you were getting a valid ac result then the continuity test should pass, given your continuity test has failed it indicates something is not quite right. you really need to determine why these tests are not consistent. as a side note have you seen this page: [http://www.aus300zx.com/forum/showthread.php?t=287789] good luck.
Yeah thats the bit that has me stumped. I have been searching the net for almost a month looking at all different threads, and yes I have seen that one. Mine appears to look normal (not popping out). I've gone ahead and bought another sensor and will check continuity and ac voltages when it arrives prior to installing. Hopefully solves the issue.. Thanks for your help
If your meter shows zero ohms continuity is not coming & going. It should show '1' then 'whatever ohms' are there. You may have had your meter on a too low ohm setting. This is generally what a '+' or '-' reading indicates on many meter. Always short your test leads together first when checking continuity. That way you know it works, & you get your base reading; that you then subtract from the test reading.
Can anyone confirm they have tested a working speedo sensor and had it read "coming and going". The second unit I have got again reads minus and positive but never open circuit.
What are you using to measure these? If a fluke meter make sure you have a decent one!! I check continuity often with cars, I don't use ohms to read it as a signal, use the beep function it's much more accurate.
Bought a auto ranging multi meter with continuity beep today. Definately was coming and going. Thanks for the suggestion. Put my second hand sensor in and no more heavy steering / no speedo. I dont have the odo working (no biggie) and tested my original sensor and continuity was coming and going aswell. strange!
Tend to disagree... ....with some of your comments. Agree that a decent multimeter is a requirement for accurate diagnostics. Fluke meters are one of the best brands of multimeter you can buy. Obviously the more expensive units can be "better" than the cheaper items, in accuracy & capability. If you want to zero out the ohms reading, use the "REL" button, available on any decent digital multimeter. As far as the beep function being much more accurate than reading the display, that is incorrect! :bash:
I only say it's more accurate because it's much easier to hear the beeping while fiddling with the connection as to watching the screen the same time especially when the signal can change so rapidly. I've read alot of your posts east coast z, no argument you know your shit better than most, just the beep helps us less skilled amateurs.
