GQ Speedo reads overspeed sometimes

[colinlamos]

Hi,

I have a 1996 GQ Ute and sometimes the speedo reads way over speed - maybe by 20% or more.

Wondering if anybody else has experienced this and if you know how to fix it.

Cheers...Colin

[GQ TANK]

Mine used to go full clockwise - a gentle knock would fix it. (sometimes)

I had a couple of dry solder joints on the pcb board.

Plus I found the legs of the 4.19 Mhz referance crystal where corroed and intermittant . I replaced the crystal with a 4.097.

I have aldo read a psot re loose connections.

[colinlamos]

Thanks for that - was it very difficult getting the PCB out?

[threedogs]

you're not the only one having issues with their speedo AB is another with speedo problems

[GQ TANK]

The speedo is easy to pull out

[mudnut]

Here is an easy test to check your speedo input signal and wiring harness:

With ignition off. If you take off the dash surround and undo the four cluster screws then lift out the cluster and tilt it to see the back.

You should be able to see the speedo signal and power inputs, which are four silver phillip drive cheese head screws. Looking from the above, (for TB42E) top one is marked 2P, the bottom is IGN. The side ones have a bit of Japenese followed by - and +. These are the speedo signal inputs.

To get a good measurement, I made two 70cm long test leads, by stripping a half centimetre of the insulation from each end. Loosen the -ve and +ve. Slip one lead under the -ve and tighten the screw, making sure that no strands of copper are loose and able to contact any other part of the circuit.

Do the same for the+ ve. Re position the cluster and do up the four anchor screws. I taped the other ends of the test leads to the probes of a digital multimeter and set the dial to AC volts. DO NOT LET THE WIRES TOUCH EACH OTHER OR EARTH DURING THE TEST.

Get an assistant to drive. See that you get a small voltage which should rise to approx 5 volts as the speed increases 60 kph. When you have finished, remove the leads and re tighten the screws, firmly, but do not over torque them.

If the signal is ok, then another unit from a wrecker or Ebay may be the go.

It is fairly easy to swap out the speedo so you can retain your odometer. Pop the black cluster shroud and clear cover off.

Unplug the odometer connector. Undo the four screws, (and also another near the high beam and indicators) and gently lift out the gauge.

The inputs are circled in yellow. The arrows point to the grey and blue input wires.

[colinlamos]

Wow - that's an awesome description. Only a week to go before we head off for an 8-10 week trip. Will see if I can fit that into the prep schedule.

Many thanks Hardcore.

[Bloodyaussie]

Wow - that's an awesome description. Only a week to go before we head off for an 8-10 week trip. Will see if I can fit that into the prep schedule.

Many thanks Hardcore.

Good on ya Craig !!!!