I have an 86 Olds Cutlass, with a 403, the car has from as far as I know factory Rally gauges,however at a confirmed 800rpm the tach reads 11-1200 RPM, at 180-190 Degrees my water gauge reads 220 Volts are always 12.5-13, I know my charging system is in good condition, my battery is strong, and when I installed the 403 I put in a braided ground strap from the head to the firewall, and a 4 gauge from the block to the frame. Whats wrong here? I used Standard motor parts sensor TX 3 for the Computer and TS76T for the gauge. Are they the right sending units?
Rally Gauges Horribly In accurate
- Thread starter 86cutlassrules
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Check the jumper tab on the tach, that's usually comes lose and the tach reads high.
The gauges on the other hand are just inaccurate period, they go off of voltage from the senders however if your charging system is putting off a higher voltage it therefore may trickle down to your sensors receiving higher voltages thus higher and inaccurate readings.
Make sure you have a 78amp 12si alternator and check the voltage on the battery.
Also, you may need to check dash the wiring for weak grounds and corroded wires behind the dash (daunting task).
These are old cars and things weather over time...
The other option (and my favorite) is to hardwire your gauges, (may solve all your problems) checkout the tech section on www.oldsgmail.com
The gauges on the other hand are just inaccurate period, they go off of voltage from the senders however if your charging system is putting off a higher voltage it therefore may trickle down to your sensors receiving higher voltages thus higher and inaccurate readings.
Make sure you have a 78amp 12si alternator and check the voltage on the battery.
Also, you may need to check dash the wiring for weak grounds and corroded wires behind the dash (daunting task).
These are old cars and things weather over time...
The other option (and my favorite) is to hardwire your gauges, (may solve all your problems) checkout the tech section on www.oldsgmail.com
One thing that helped all of my guages (except volts- still reads low) , take your rally cluster out and give all the nuts on the back an 1/8th of a turn( DO NOT CRANK ON THESE THEY WILL BREAK!!! :shock: !!), just enough for a better ground/connection contact, works wonders. Was chasing all kinds of guage problems... from fuel not reading to the tach being fast/sluggish.
seem to see this question once a month or so.............
Erratic/High Tach Fix
http://tech.oldsgmail.com/eint_tach_fix.php
peace
Erratic/High Tach Fix
http://tech.oldsgmail.com/eint_tach_fix.php
peace
That's exactly what I did to my GP tach. The jumper was broken, so in a rare moment of genius, I soldered it. And in my Malibu, loosening and re-tightening the screws straightened the gauges right out.
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