I've searched but haven't been able to get a clear answer.
Speedo & tach are way off. For lack of better wording, they both seem to keep spinnin till they max out..

I would hate to have to purchase a cluster.

Any ideas or info would be greatly appreciated.

Thx

 

For instance .. I'm driving about 40 MPH and speedo reads 90 and just keeps going up till it hits the 145 mark

 

Maybe tire/rear gear combination, are you sure the gears havent been changed?

 

this is a very typical problem with the third gen series cars. mine for instance is only the rpm gauge, which reads 2500 at idle and 6500 at 55mps in 5th(5 speed 305) there is a post some where on this site to remedy it. if i remember correctly, they had to change a resistor or something in the cluster.

 

how long have you had the car?
Is this a recent development?

 

The problem is common to the 90 -92 speedos like your car
https://www.thirdgen.org/forums/elec...meter-fix.html

Given he has both tacho and speedo problem which are completely separate from each other wiring wise ,
I suspect his problem is within the cluster itself ( or it's grounds )

 

Since 11/11
I was "hot wired" (wires soldered to circuit board)
I replaced the unit and also replaced the speedo cable.. and now it goes crazy.

 

Could be your speedo cable, the one from the tranny to the speedo housing (or in my case from the tranny to the step-down box then to the speedo housing). The cable could be old and weak or could have loosened off of the tranny threads.

 

https://www.thirdgen.org/forums/inte...eedo-woes.html

JamesC

 

I had a similar issue with my '99 Chev 2500 van. The speedometer would read over 100 mph when actual speed was probably only 35. The pre-set speed limiter would cut the engine at that point.
It turned out to be the ECM. There was a break in the seal and moisture caused corrosion of the aluminum case which led to white powder on the circuit boards. Add humidity and something was shorting out giving false readings from the didgital speed sensor.
Put in a salvage yard ECM and the problem was gone.

 

I noticed the trip was not functioning properly..
I reset to zeros drove a mile and had 900 miles on trip..
I will have to look into it..

Thank for all the responses .. Its much appreciated