10-03-2020, 05:17 PM
It being fine and warm - if a little windy - I have tackled the non-working petrol gauge in the RP. It has only ever moved a fraction when the ignition is turned on/off. Following Malcolm Watts (Cornwall A7 site) tests I determined that the sender unit is at fault and sure enough I found the float full of fuel. So far, so straightforward - but...
When I had sorted the float I wired everything back up to test the unit before putting it back on the tank and I find it reads in reverse! With the float up the gauge shows empty. With the float down it shows full. The gauge moves with the float going up and down, just in reverse.
I strongly suspect the sender is not for an A7 (from my MG knowledge I know that full and zero resistance can be at 'full up' or 'full down' depending on the type of sender).
Unless someone can tell me I have done something daft with the wiring to cause the reverse reading I guess I am looking for a replacement sender unit.
When I had sorted the float I wired everything back up to test the unit before putting it back on the tank and I find it reads in reverse! With the float up the gauge shows empty. With the float down it shows full. The gauge moves with the float going up and down, just in reverse.
I strongly suspect the sender is not for an A7 (from my MG knowledge I know that full and zero resistance can be at 'full up' or 'full down' depending on the type of sender).
Unless someone can tell me I have done something daft with the wiring to cause the reverse reading I guess I am looking for a replacement sender unit.