davek Posted July 13, 2019 Share Posted July 13, 2019 (edited) Fellas I can start the car and drive a couple minutes when the oil pressure & water temp gage needles work there way to zero rather quickly. At home I connected my voltage meter to the connector at the water temp sensor and to ground. Turned the key on and I get a 0 - 10 volt sporadic pulse. Every 1-2 seconds-I tried to attach video by it says unsuppoeted Same when I hook up to oil pressure sensor. Steady 12.5v at the console fuse. Haven't tried either wires t the gage itself. Probably a itch to get to? any ideas? Edited July 13, 2019 by davek Quote Link to comment Share on other sites More sharing options...
davek Posted July 13, 2019 Author Share Posted July 13, 2019 I understand electrical problems but what causes a sporadic pulse. Quote Link to comment Share on other sites More sharing options...
jhm Posted July 14, 2019 Share Posted July 14, 2019 Poor connection? Poor ground? Failing sensor? All of the above? A simple double-check of your water temp can be made with a cheap IR gun. Quote Link to comment Share on other sites More sharing options...
Miles Posted July 14, 2019 Share Posted July 14, 2019 Make model and year of the car? Any modifications to the car? Stock gauges? Describe what happens to the temp gauge if you ground the wire connected to the temp sensor. Quote Link to comment Share on other sites More sharing options...
davek Posted July 14, 2019 Author Share Posted July 14, 2019 (edited) 73 240Z Stock gauges Megasquirt MS3 running for a few years now. I just finished an electric steering installation. But this issue started before the steering project. Temp sensor to ground test--- Needle works its way to 250 degrees and bounces around a little with voltage pulse. after 15-20 seconds needle drops to 3/4 range and bounces there then back to full hot. back and forth This test and previous test was with MS3 completely disconnected-fuses pulled. While engine running with tunerstudio online temp is normal and steady. To test both temp & pressure gauges I would need to disconnect the wires at the gauges and reconnect with a different power source like straight to a battery, to eliminate all car wiring correct? And if I could get to the wires I need to check voltage feeding the gauges for a pulse. fun fun fun Edited July 14, 2019 by davek Quote Link to comment Share on other sites More sharing options...
Miles Posted July 15, 2019 Share Posted July 15, 2019 (edited) So if you turn the ignition switch to "run", pull the wire that connects to the temperature probe and then ground the wire, the temp gauge should go all the way to full hot. If, while performing this test, the gauge bounces around, then there is an issue with the sensor wire or the gauge. Could be loose or dirty connections. These links may be of some help: https://www.zcar.com/forum/10-70-83-tech-discussion-forum/280481-oil-temp-gauge-not-working.html https://www.zcar.com/forum/10-70-83-tech-discussion-forum/47277-temp-gauge-not-working.html Edited July 15, 2019 by Miles Quote Link to comment Share on other sites More sharing options...
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