CAN A 90 TACH BE FIXED OR CHANGED
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
CAN A 90 TACH BE FIXED OR CHANGED
Well my tach messed up a year ago , pegging itself with the slightest acceleration !
A parts fellow told me to replace the CAPASITOR with part # 477371 , tried that today but no go ! :mad anyone know of a fix or a neat replacment tach preferabily in the stock location !
A parts fellow told me to replace the CAPASITOR with part # 477371 , tried that today but no go ! :mad anyone know of a fix or a neat replacment tach preferabily in the stock location !
Team Owner
Joined: Apr 2000
Posts: 27,818
Likes: 8
From: CT
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
You're honestly better off getting an auto meter 2302 tach. It's accurate and you'll never need to worry about a jumpy tach any more. I have one and love it. Nice shift light too! Summit sells them.
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (JD 90 383)
Well I just applied for a new Summit and Jeg's , and don't have any problem with going for a after market ( no doubt better ) but would like to find one that could be installed in the dash where the stock one is if possible ! :confused:
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
Joe, have you considered removing the tach filter and seeing if that works?
:confused:
I have the MSD 6AL on my car, I removed the filter (capacitor) and it works just fine now.
:confused:
I have the MSD 6AL on my car, I removed the filter (capacitor) and it works just fine now.
Advanced
Joined: Mar 2002
Posts: 65
Likes: 0
From: sharpsburg GA
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
Hey Joe,
my tach also pegs out when I start the car and then it slams back to zero. The best I have been able to find is to get the hole cluster reconditioned for $275.00 at american corvette. I would like to give the capacitor a try though. Is that part number a chevy dealer part number? Also can you explain to me were the capacitor is on the board, I have already had the cluster out once and took a look at the board.
THANKS ALOT.
my tach also pegs out when I start the car and then it slams back to zero. The best I have been able to find is to get the hole cluster reconditioned for $275.00 at american corvette. I would like to give the capacitor a try though. Is that part number a chevy dealer part number? Also can you explain to me were the capacitor is on the board, I have already had the cluster out once and took a look at the board.
THANKS ALOT.
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (bdtenore)
OK THIS IS THE SCOOP !
PERTAINING TO ONLY 1990 , TACH FILTER ! THATS WHAT THEY TELL ME IS THE PROBLEM ! THIS PART LOOKS LIKE A OLD CAPASITOR , LIKE WE USED TO BUY WITH A NEW SET OF POINTS ! GM NO LONGER CARRIES THIS PART FOR THE 1990 CORVETTE ! I WAS TOLD THIS WOULD WORK !
HARD TO FIND , HAD TO REMOVE THE WIPER MOTOR , UNPLUG THE TACH WIRE FROM DISTRIBUTER CAP AND FOLLOW IT DOWN , BOLTED ON BACK OF LEFT HEAD ( DRIVER'S SIDE ) THEN WIRE GOES TO A PLUG ! I CHOSE TO UN - PLUG , CUT OFF BOTH ENDS AND CAREFULLY REMOVE WITH THE AID OF A SMALL SCREW DRIVER TO UNLOCK , THEN INSTALLED THEM ON THE REPLACMENT FILTER ( AC DELCO # 477371 ) $6-$8 NO BIG DEAL IF IT HAD WORKED , O YA I ALSO CONNECTED A GROUND WIRE TO IT , WHERE IT IS SUPPOSED TO BOLT TO HEAD AS IT WOULD TAKE A BETTER MAN THEN ME AND RAN THE GROUND WIRE TO A MORE CIVILIZED LOCATION , I DO NOT KNOW IF THIS WAS NECESSARY !
GOOD LUCK AND IF ANYONE KNOWS WHERE I MIGHT HAVE MESSED UP I AM ALL EYES !
PERTAINING TO ONLY 1990 , TACH FILTER ! THATS WHAT THEY TELL ME IS THE PROBLEM ! THIS PART LOOKS LIKE A OLD CAPASITOR , LIKE WE USED TO BUY WITH A NEW SET OF POINTS ! GM NO LONGER CARRIES THIS PART FOR THE 1990 CORVETTE ! I WAS TOLD THIS WOULD WORK !
HARD TO FIND , HAD TO REMOVE THE WIPER MOTOR , UNPLUG THE TACH WIRE FROM DISTRIBUTER CAP AND FOLLOW IT DOWN , BOLTED ON BACK OF LEFT HEAD ( DRIVER'S SIDE ) THEN WIRE GOES TO A PLUG ! I CHOSE TO UN - PLUG , CUT OFF BOTH ENDS AND CAREFULLY REMOVE WITH THE AID OF A SMALL SCREW DRIVER TO UNLOCK , THEN INSTALLED THEM ON THE REPLACMENT FILTER ( AC DELCO # 477371 ) $6-$8 NO BIG DEAL IF IT HAD WORKED , O YA I ALSO CONNECTED A GROUND WIRE TO IT , WHERE IT IS SUPPOSED TO BOLT TO HEAD AS IT WOULD TAKE A BETTER MAN THEN ME AND RAN THE GROUND WIRE TO A MORE CIVILIZED LOCATION , I DO NOT KNOW IF THIS WAS NECESSARY !
GOOD LUCK AND IF ANYONE KNOWS WHERE I MIGHT HAVE MESSED UP I AM ALL EYES !
Advanced
Joined: Mar 2002
Posts: 65
Likes: 0
From: sharpsburg GA
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
Hello again Joe,
Yup I know all about messing with the tach filter. Instead of replacing the filter I diconnected mine at the plug at the fire wall, so all I had now was a wire ( not connected to anything )going to the cluster. So now when I start up the car the needle slowly rises and pegs out instead of spiking . It must be somthing inside the cluster since it still pegs out with the cluster disconnected to the distributor and tach filter. I wish I could find a wiring diagram of the cluster ther cannot be many components on the board.
Yup I know all about messing with the tach filter. Instead of replacing the filter I diconnected mine at the plug at the fire wall, so all I had now was a wire ( not connected to anything )going to the cluster. So now when I start up the car the needle slowly rises and pegs out instead of spiking . It must be somthing inside the cluster since it still pegs out with the cluster disconnected to the distributor and tach filter. I wish I could find a wiring diagram of the cluster ther cannot be many components on the board.
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (bdtenore)
WOW , STRANGE ONE , I DID THIS FILTER THING ABOUT A YEAR AGO BUT THE FIRST TIME I DID IT I CUT THE ENDS OFF AND SOLDERED THE OLD ONES ON , THOUGHT I MIGHT OF OVER HEATED SOMETHING BECAUSE IT DID NOT WORK THAT TIME EITHER , SO I UNPLUGED THE WIRE FROM THE TACH AND LEFT IT LIKE THAT TILL TODAY , WHEN IT WAS UNPLUGED IT DID NOTHING !
MUST NEED A RESISTOR , IF I HAD JUST STAYED IN SCHOOL :smash:
NOT YELLING , JUST NEED NEW SPEC'S :D
MUST NEED A RESISTOR , IF I HAD JUST STAYED IN SCHOOL :smash:
NOT YELLING , JUST NEED NEW SPEC'S :D
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Oct 1999
Posts: 6,366
Likes: 34
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
I was talking about by-passing the tach filter.
When you removed the wire from the distibuter, you removed the tach signal completly. It will not work if you remove the filter wire from the distibuter.
I was wondering what happens when you cut out the filter/capacitor and use wire in it's place. It might work half-assed...
My tach went crazy in my 90, I installed the MSD and used the MSD's "tach out" line for the tach, with the tach filter cut out. My tach works perfectly fine now. I dont know if this will defently solve your problem, but being there is not a replacment filter out there, and aftermarket has not made a tach that fits in place of ours, it might be a possibility.
When you removed the wire from the distibuter, you removed the tach signal completly. It will not work if you remove the filter wire from the distibuter.
I was wondering what happens when you cut out the filter/capacitor and use wire in it's place. It might work half-assed...
My tach went crazy in my 90, I installed the MSD and used the MSD's "tach out" line for the tach, with the tach filter cut out. My tach works perfectly fine now. I dont know if this will defently solve your problem, but being there is not a replacment filter out there, and aftermarket has not made a tach that fits in place of ours, it might be a possibility.
Advanced
Joined: Feb 2001
Posts: 79
Likes: 0
From: Brisbane, Queensland,Australia
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
I have the same problem with my 90 !! I also tried by passing the Tach filter and had no change. I have read in previous posts that it has something to do with interference where the wire passes through the firewall. Apparently the wire wasn't insulated enough (problem caused by being the 1st year of the new dash !!). Anyway, i am also interested in hearing from anyone that has fixed the problem !
Thanks
Steve
Thanks
Steve
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (sm90)
Well this is my last attempt at trying to find a repair , if non is out there I will try and find a gauge that I can install in the dash where the stock one is now , just hate to butcher it if I don't have to .
My luck someone will come out with a fix after I have cut mine out ! :mad
My luck someone will come out with a fix after I have cut mine out ! :mad
Advanced
Joined: Mar 2002
Posts: 65
Likes: 0
From: sharpsburg GA
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
Has anyone tried checking out the wire coming throug the firewall? Some kind of intrferance would make sense. I have felt from the get go that it is getting power from some other source, or that the cluster had a bad ground. I checked all my grounds and they were good. As soon as I get some free time I am going to find were that wire comes through the fire wall and check it out.
If i were you I would do that before tearing up the factory look.
Good luck, and keep postig results.
If i were you I would do that before tearing up the factory look.
Good luck, and keep postig results.
Melting Slicks
Joined: Apr 2002
Posts: 2,308
Likes: 1
From: Portsmouth VA
Re: CAN A 90 TACH BE FIXED OR CHANGED (bdtenore)
my tach is all hosed up too!!! anybody tried sending it out to be repaired? if so, how well did that work and what was the cost? if they can fix it by just sending the cluster in, then it seems to me that it wouldn't have anything to do with any bad grounds or filters or whatever, right? it would have to be something on the cluster itself... hmmmm
anybody???
anybody???
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (SonnyinVA)
If that would fix it I would be happy to pull it out and ship it off , but I have read at least 2 other postings on this problem and have talked to 3 GM service manager's and they all blame the tach filter ! It is like it was desighned to work on 6 volt and all of a sudden its getting 12 ! Had one fellow on here said he was going to find out what the value of the filter was and make his own , never got back to me on that one , if it is a interferance thing only on the 90 I would think what ever they did to the 91 would be the way to go !
Anyone ???????? :confused:
Anyone ???????? :confused:
Advanced
Joined: Mar 2002
Posts: 65
Likes: 0
From: sharpsburg GA
Re: CAN A 90 TACH BE FIXED OR CHANGED (Joe)
Today at work I checked out a friends 1990 tach (his is working) . I disconnected the lead from his distributor and his tach went dead, just as it is suppose to. So if the broken tachs problem is with the tach filter, how come when I disconnect the wire at the firewall totally isolating the tach filter the tach needle still moves up and pegs out but only at a slower rate?
Thread Starter
Racer
Joined: Feb 1999
Posts: 274
Likes: 0
From: summerfield ( Villages ) FL.
Re: CAN A 90 TACH BE FIXED OR CHANGED (bdtenore)
I got tired of mine peging the tach so I unplugged the wire from the distributor and nothing , and I mean nothing drove to Miami and back 500 miles and it didn't even bounce on their rough roads down there !
So if yours still works unplugged " got me " :confused:
So if yours still works unplugged " got me " :confused:
