Trip Computer, Intermittent fuel and temp readings

[mtxm]

On my 1993 SEI most of the time I have no mpg readings, just flashing '---s', although figures have appeared occasionally. I assume that a poor electrical connection is to blame, but I have no idea what to check. The 0C temperature reading is also wildly amiss (+30 or so) and again a correct reading has been spotted once or twice, so I am not sure what the problem is there, perhaps a miscalibrated sensor? Any comments/ suggestions would be greatly appreciated. Regards, Matthew T.

[xmexclusive]

Hi Matthew

The flashing of the display is typical of the result of a battery disconnection. It may be that you have a poor/intermittant connection on the 12 volt feed wire to the display. The usual suspects are the wire connections to the multipin plug into the back of the display or the contact pin soldering on the display printed circuit board. If you have a spare working display plug that in. If it works sort the old display. If it still plays up then sort the wiring.

John

[mtxm]

Hi John,

Thank you for your suggestions. The odd thing is that the clock, temperature gauge and speed indicator functions on the display all work as normal, apart from the very high temperature readings already mentioned. I have noticed that there are several electrical connnections around the inlet manifold and I wondered if they might be for sensors and worth checking?

Best regards,

Matthew T.

[DrTim]

I had fluctuating temp once on an ebay replacement mirror for the prestige, just swapped the sensor over form the old one I think, or maybe the whole mirror electronics.

[rowanmoor]

Temp is likely to be the sensor in the passenger wing mirror. It is a standard part across a number of models that can be obtained from the stealers reasonably cheaply (at least it was a couple of years ago). You need to cut the wires and patch the new one in though.

[mtxm]

Thank you Dr Tim & Rowanmoor. I have had problems with temperature sensors before, but only when they failed completely, rather than just incorrect readings. It may be resolved by changing the sensor as you suggested and I think I have a functional spare. In relation to the fuel consumption readings, I fiddled with the wires on the mainfold and I now have a convincing range figure at least!! Regards, Matthew T.