Tach test

Would it be possible or even smart to say hook up my test light while the engine is running to ground and then touch it to the send post on the tach. If it flashes then the tach is bad? I have checked all the wires and they are good but the tach wont power up at all from what i can tell. The needle doesnt move at all. I was thinking before i through a tach into it after the rectifier was put in that this may be a good test.

Re: Tach test

Dont know if the tach signal is electic current. If it is, then probably not enough to lite a bulb.

Re: Tach test

It had me scratching my head a bit trying to determine how the tach reads the pulses - I think you would be OK using a 12V LED as that has a current limiting resisitor in there and you shouldn't be risking anything - I would not use an incandescent bulb as the current draw may be too high. Remember that LEDs are diodes and will only work one way round so the 12V leg should be towards the engine.

Re: Tach test

Ok i just have a regular old 12v test light nothing special about it. So i may just try running a test lead back from the engine to the tach. But i am getting power and a good ground if the new wire doesnt change anything i suppose the next step is a tach. But can only test it out at the lake dont have anyway of hooking up the muffs at my apartment. Which does suck at times. Will post up results later tonight heading to the lake in a few hours. Thanks for the answers guys.

Re: Tach test

so i have a update which i really believe leads to getting a new tach. I never got to hook up the new test wire to the back off the motor. I fired up the motor and straight out the gate the needle started acting like it was working then there was a loud pop and the gauge stuck at what ever it was at and then a very loud whine came out of the tach. So i am assuming that means the the gears or whatever turns the needle inside of it snapped and or gave out. I did find a place today that will sell me a new/used 20 pole tach for around 20 bucks so I will be picking up one on friday hopefully if I can get over there. Also I guess the new rectifier is working rather well. I was running full WOT and was getting right around 15.5 volts off the battery i know it is a tad high but I am assuming it is ok due to it never got higher then that and when I throttled back down it would go back to around 13 volts.