ewdickerson

I have a 91 convertible with a tach going haywire and got a new tach filter. Where physically does it go? Got the schematic, but it's not clear where it goes. Help!!!! Thanks!!!!

Jamesnns

PM sent.

I've read the tach filter is rarely the problem.
After much reshearch, this is what I did.


DISCONNECT NEG BATTERY TERMINAL.
Drop your drvrs hush panel,
drop your steering wheel( 2 bolts)
Remove dash cluster (4 screws)
Remove tach circuit board.
Go to radio shack and buy either 1 200K 1/2 watt ohm resistor, oR two 100K 1/2 watts reistors and solder then together for a total of 200kohms.
Solder this from Pin 4 to pin 10 on the board. The pic shows front, easier to do at back of board. Use shrink tubing or electrical tape as not to short.
Cut, or scratch thru the exsisting path between the "old" route between pins 4 and 10.
Reinstall reversing instructions.

It's really not that hard to do.

Good info here
http://www.thirdgen.org/techboard/el...ter-fix-3.html

Not "my" pic.


It took me quite a while to find this info..good luck.


or, you can send it out for $275-400 and have someone else do it.
Or you can swap a new cluster in.

You'll get with-in 50-75 rpms.

ewdickerson

don't understand your comment.

Muffin

He has sent you a private message, likely some info on your problem. Look in the upper right area of your computer screen, you should see a small window saying welcome ewdickerson followed by a notice you have a PM. Click on "Your Notifications".

Jamesnns

Sorry, feel free to just call me.

rodj

90/91 cars have well documented problems with the cluster itself.
New filter seldom fixes problem

http://forums.corvetteforum.com/c4-g...1990-vert.html

http://www.thirdgen.org/techboard/el...meter-fix.html

HlhnEast

Is this problem common in earlier years as well? My tach jumps when I crank the car but goes to zero after that with intermttant jumps.

65Z01

On my '88 the tach filter is bolted to the upper bell housing to the left of the dist.

rodj

Tacho fault as outlined above is unique to 90 /91 cars.
In earlier cars, tacho problems are usually the filter or bad wiring.Check the wiring on the tach filter itself; have seen many where the wire is nearly broken off

jeffp1167

My 1990 does this crap too, motor sounds like it is idling normally but tach always shows about 1100rpm. Then when you tap the gas pedal the tach skyrockets way faster then I think the motor is actually turning. Thanks for the link!

kittmaster

It is important to note that the resistors are to be soldered in a SERIES connection and not together as PARALLEL. If soldered in parallel, the end result will be 50k, not 200k as required.

SERIES connection looks like (WHAT YOU DO WANT TO DO IF YOU BUY THE TWO 100K RESISTORS):



PARALLEL connection looks like (WHAT YOU DON'T WANT TO DO)"