Electric tach doesn't work
Thread Starter
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Electric tach doesn't work
I converted my tach to HEI, and installed an electric tach from a 75 to match. It seems to be wired in correctly, but it doesn't work. Is there any way to test the tach itself without pulling it out of the dash? Does anyone have any ideas for troubleshooting? The tach is getting 12V and the ground is good.
Thanks
Ken
Thanks
Ken
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Re: Electric tach doesn't work (bb69)
How handy are you with electronics? I have a schematic of a tach tester I designed. You could build it "bare bones" (no box, no fancy connectors etc) for about $10-$15.
[Modified by zwede, 9:54 PM 4/1/2002]
[Modified by zwede, 9:54 PM 4/1/2002]
Thread Starter
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Re: Electric tach doesn't work (zwede)
Zwede,
I'm not too handy with electronics, but I know some people who are. I was hoping you might see this message. Thank you for the wiring information for the tach a few months ago. I connected the tach according to your instructions. I would love to see your schematic for a tester. Is it possible to test the tach in the car if I can get to the connectors?
Thanks for your help.
I'm not too handy with electronics, but I know some people who are. I was hoping you might see this message. Thank you for the wiring information for the tach a few months ago. I connected the tach according to your instructions. I would love to see your schematic for a tester. Is it possible to test the tach in the car if I can get to the connectors?
Thanks for your help.
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Re: Electric tach doesn't work (bb69)
Yes, the tach can be tested in car. However, if it doesn't work when connected to the HEI, it's not going to work with it connected to the tester. I used the tester to calibrate the tach. It has a switch on it. Position one makes the tach show 1000 rpm. Position 2 makes it go to 5000.
Question: What happens when you turn the ignition on? The needle should go to zero.
If it doesn't move, make sure you really do have voltage and ground. If that checks out there's really not much more to do but to get a replacement circuit board. The first tach I got was dead also. Gary Gruhala sent me another one, and it worked, but was badly calibrated.
Question: What happens when you turn the ignition on? The needle should go to zero.
If it doesn't move, make sure you really do have voltage and ground. If that checks out there's really not much more to do but to get a replacement circuit board. The first tach I got was dead also. Gary Gruhala sent me another one, and it worked, but was badly calibrated.
Thread Starter
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Re: Electric tach doesn't work (zwede)
Zwede,
Nothing happens to the tach, it always sits on zero. I will try to check the voltage and ground at the terminals to confirm it is getting power.
Thanks
Ken
Nothing happens to the tach, it always sits on zero. I will try to check the voltage and ground at the terminals to confirm it is getting power.
Thanks
Ken
