Speedo not speedy

[5.0ltr]

Right, I have checked the bible but it does not seem to conform to the defect/faults listed. It started yesterday with the speedo being intermittant, dark so could not see odometer/trip. Had a look today. Speedo and odometer do not work, but, if the loud pedal is given some beans it all starts albeit not reading correct speed (low) the actual speed seems unimportant as long as over 40ish, and the more right foot given the higher it reads, but, as I said it is under reading speed. The odometer then starts working as well. All other gauges, electrics working. Any thoughts,thanks, Bob.

[Chimjunkie]

Sounds like a problem with the calibration electronics box of tricks between the speedo and sensor. Or possibly the sensor alignment. Unlikely, but a small stone could get caught and knock the sensor away slightly.

[dnb]

There is no box of tricks between the speedo and sensor. The box is there to provide the speed input to the ECU.

[Chimjunkie]

dnb said:

There is no box of tricks between the speedo and sensor. The box is there to provide the speed input to the ECU.

I stand corrected! Sorry.

[spend]

All the dash looms I've seen use a common power and ground wiring, which would indicate a break in the dash loom if only the speedo & rev counter are faulty. Some of them were crimped in 'daisy-chain' fashion so a new crimp may be all thats required rather than having to strip the loom completely.

Dave