OkeeGuy

my tach is no longer acurate...as a matter of fact it acts screwy...
ive heard that a new tach circut board will fix this...
what do you think?
AND...
wheres the best place to buy one and how much do they cost?


[Modified by SIGNGUY, 7:38 AM 7/2/2003]

mrvette

First off, I would replace that tach filter with a known good partl.....or search here for the schematic of the thing, and build one.....it's essential to get smooth readings from the tach....otherwise you get all sorts of jumping around and uneven responses....

GENE

OkeeGuy

thanx Gene :) last year it was acting a little funny sometimes so while at Carlisle i talked to several people about tach filters...
one was a guy that repairs clocks, speedos and various gauges for vettes...
i cant remember the name of his business but i DO know that it is a popular one that many here would recognize...
anyway...what he told me was that if it is working at all...the filter is good...
he said that if the filter was bad...the tach wouldnt work at all...
if the tach is sparatic...it is the board OR one of a few other things...

the other guy that i spoke with sold tach filters...
he in no uncertain terms told me that he would be happy to sell me a filter but he felt confident that it would not fix my problem and that he agreed with the other gentleman that i had spoken with...

as it turned out...my problem was a bad module in the distributor...
replaced the module (actually a whole new distributor) and the tach worked fine...(for a year)
now it is acting funky again...

now i want to say that i DO respect your knowledge and experience Gene and i in NO WAY mean to dispute what you are saying...
and i DO appreciate your inpute on this matter...
im just telling you what my experience has been on this subject and would be interested in knowing what you think anbout it...
thanx Gene :)

mrvette

Well, I have gone through hell with a '70 GTO dash tach, where the thing was totally FUBARED, no worse than that even....I wound up replacing everything at once....and I fougt hard, the meter/movement coil was bad....intermittant, I was SO pissed after all that work and those dashes are difficult too, as all early cars are....wasn't untill in the 80's that any of that crap was ever easy to fix.....
NOW on my vette here I traded the old cable dist. housing for the electronic tach in the car now...I think it's a replacement tach, not sure...but anyway it's from a 75-77 style vette...and needs the filter, or my home built....
now I have never knock on wood, had any troubles from that tach....guess i'ts next..been 7 years so WTF, why not???

I still think it's the tach filter....but YES, it COULD be the tach/board also...

90% chance it's the filter though....

GENE

OkeeGuy

Gene...
well im not saying you are wrong cause i really dont know for sure either...
all i know is that 2 different vendors could have easily sold me one at $50+ and advised me not to buy one cause it wouldnt fix the problem...
it would be great if someone would post that has had experience with tach boards...
we both might learn a thing or two... :yesnod:
anybody???


[Modified by SIGNGUY, 8:34 PM 7/2/2003]

wombvette

I have been running mine with no filter for more than a year now, 10K+ miles with absolutely no problems. No eratic operation etc. and its still working, so you might want to take the filter out just as a test.

OkeeGuy

hhhmmmm...
interesting...
i think ill try that...

Michael Tucker

i also removed the filter some time ago and now im thinking it might show a lower reading if i had one in? i guess i need to check it out.

$50+ i would have got one if i could have found one before i took mine out

does it do any harm leaving it out? been about a year for me too and i drive over 12000 a year

Mike

Schmucker

My tach bounces about 2000rpm. While playing in the engine compartment I found that my tach filter was not grounded. I grounded it and now I just need to get the car ready to start to see if the tach works okay.

OkeeGuy

grounding it is a good point...
it grounds thru thr mounting bracket...right?
well, i now have an aluminum intake...does aluminum conduct electricity?



[Modified by SIGNGUY, 6:58 AM 7/3/2003]

Paul L

Yes it does. Many homes in Canada are outfitted with aluminum wiring.

Jaxtoy

I had the same problems with my '79. I talked to everone that had any information on corvette electrical systems and made the choice to replace the tach board. The total time to replace the board is about 45 min. or less.
The tach is back to it's old self and i'm kicking my butt for not fixing it sooner. The problem was two fried resistors on the circuit board.

I ordered the tach circuit board from:

http://www.RICK'SVET.COM

The price was $67.95. Great service. Hope that this will solve your problem.

Good luck, Jack

Koz

I spoke to the guy at http://www.redlineg.com/ about my tach.
He said that as long as it's working then a new circuit board wouldn't help. He said I could recalibrate it.. He told me to open the console to expose the tach, hookup an external tach and give him a call back and he'd walk me through it.. :eek: :eek: Now that's service. I haven't taken him up on it yet but I plan too.. My tach is running about 7K over what it should be but it's consistant.. If yours it jumping all over the place you may have other problems.. Give'em a call.. Good luck!

Andrew

Let us know if you get it working. I've been trying different things with my 79 and have not found a fix yet. My tach works, but stops at 1100 rpm. It will not go any higher. I purchased a new board from a well know Corvette distributor and then the tach would not even register. It didn't move on start, reving, or even when I rolled the windows up. :lol: I'm very interested if you find a fix.

PROSOUTH

Signguy, I have several tachs and boards stored up. If you need one I can let you borrow one to see if that is your problem or sell you one reasonably.

PS Guys these tach filters are way over priced. I got mine for a dollar off of an S-10 Blazer with a factory tach at the junkyard. There isn't any difference in them except maybe the plug on one end. Jim :seeya

Andrew

Prosouth,

If you don't mind and have an extra circuit board that you know works, I'd be interested in "borrowing" it from you and if it worked would gladly purchase it from you as well. Just let me know.

OkeeGuy

BTW...where the heck is the board located in the car?

Andrew

It is behind the tach itself. To get to it, there are several screws holding the speedo/tach lens in place. After removing the lens, there are some hex screws holding the plastic bezel that is placed over the tach and speedo. Once this is removed, more hex screws holds the tach in place. After the screws are removed, you can gently pull the entire tach out. You'll see the board on the back of the tach. There are just 3 nuts holding the board in place. Make sure you remember which side faces the tach.

Then you just reassemble. Make sure that you do not over tighten any of the screws that holds the speedo/tach bezel or lens. They crack easily (don't ask how I know that).

baja216

Has anyone written or found any detailed procedures on changing out the tach board? I've heard someone say you need to drop the steering column.

:auto:

Andrew

I didn't drop the steering column. Everything will come out without doing that. However, if you are going to take the entire speedo/tach cluster out (the plastic case) then you must drop the column.

I'm not sure if anyone has written a more detailed procedure, but if you do what I said in the last post, you should be fine. It is very easy. I just wish getting the tach to work was that easy :lol: