tach still not working..what next ??
Thread Starter
Racer
Joined: Mar 2002
Posts: 499
Likes: 0
From: honolulu HI
tach still not working..what next ??
well my tach isnt working..i just replaced the circuit board with a new one but it still doesnt work..when i start the car up the tach jumps,then sits at 0..when turned of the needle drops below 0..
should i just get a new tack and mount it on the steering coloum? how do i wire up a new tach? easy project or not? i give up on mine for now im too frustrated :mad
should i just get a new tack and mount it on the steering coloum? how do i wire up a new tach? easy project or not? i give up on mine for now im too frustrated :mad
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Re: tach still not working..what next ?? (razz1980)
Under the hood is a thing called a tach filter, it's black about 1/2 inch diameter with a mounting clip for a 3/8 bolt and a wire in each end....
plugs into harness, and then into HEI....follow white HEI wire you will find it....AFAIK....i'ts not available....so you need build one from parts...electronic pars, and solder up the connections, and use the present wires....
do a search here on forum, and the topic should pop up....with a schematic/wiring diagram of the unit....
another way to prove the point temporarily would be to take that white harness connector that goes to the tach filter, and putit directly to the HEI and see if the tach registers anything at all....if it does, it will be jumpy and inaccurate, if it don't you need fix the present tach....or maybe the wiring is bad...
GENE
plugs into harness, and then into HEI....follow white HEI wire you will find it....AFAIK....i'ts not available....so you need build one from parts...electronic pars, and solder up the connections, and use the present wires....
do a search here on forum, and the topic should pop up....with a schematic/wiring diagram of the unit....
another way to prove the point temporarily would be to take that white harness connector that goes to the tach filter, and putit directly to the HEI and see if the tach registers anything at all....if it does, it will be jumpy and inaccurate, if it don't you need fix the present tach....or maybe the wiring is bad...
GENE
Safety Car
Joined: Mar 2000
Posts: 4,078
Likes: 27
From: Northeast South Dakota
Re: tach still not working..what next ?? (mrvette)
mrvette nailed it. It does kind of sound like the tach filter. The tach filter and the circuit board are about all there is to go wrong. Bypassing the filter is good advice. That way you will know whether that's the problem or not. I am going to look around. There has to be someplace to purchase a tach filter. Every aftermarket tach I have ever put in comes with one. They aren't the same as the ones on our vettes, but would fit inside the tach filter "canister thing" that is there now. The filter that came with the tach I put in my pickup is just slightly larger than the eraser on a pencil.
-Justin
-Justin
Racer
Joined: Mar 2002
Posts: 369
Likes: 1
From: Nowhere
Re: tach still not working..what next ?? (razz1980)
I would bypass the tach first to see if that was the culprit. My problems was the tach board itself. But after a while the tach filter gave out, and I had to replace it also.
I bypassed the filter, just to see if that was it, and the tach worked. I noticed at low RPM's it worked fine, but higher RPM's it jumped and skipped. I replaced the tach filter and it is back to working properly now.
I found 3 places that had filters on the net, and did so much searching, I thought I would never find one. And of course, everybody wanted a pretty penny for theirs. I did manage to find a guy that had 5 or 6 left, and got it for $68.00 or so. Everybody else wanted $100.00 or more.
Here is a link to the post I made last week. I only had his e-mail address, but he does respond to his mail. Hopes this helps.
http://forums.corvetteforum.com/zerothread?id=271447
I bypassed the filter, just to see if that was it, and the tach worked. I noticed at low RPM's it worked fine, but higher RPM's it jumped and skipped. I replaced the tach filter and it is back to working properly now.
I found 3 places that had filters on the net, and did so much searching, I thought I would never find one. And of course, everybody wanted a pretty penny for theirs. I did manage to find a guy that had 5 or 6 left, and got it for $68.00 or so. Everybody else wanted $100.00 or more.
Here is a link to the post I made last week. I only had his e-mail address, but he does respond to his mail. Hopes this helps.
http://forums.corvetteforum.com/zerothread?id=271447
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Re: tach still not working..what next ?? (razz1980)
I built a tach filter for ~$7 based on a schematic provided by Smokehouse69. I took pictures of it. Let me know if you need to see them.
http://forums.corvetteforum.com/zerothread?id=136220
http://forums.corvetteforum.com/zerothread?id=136220
