NB 1.8 (2.5) Engine fault when hot, crank sensor fixed it

[rhino666]

@Paul W

Rhino, thanks for your input via P.M.

Having now checked for fault codes the car is actually showing a 0120 fault (TPS = Throttle Position Sensor).

Not what I expected hopefully a far less expensive fault to fix than a new coil pack. I’ve just removed the TPS from the car and tested its rate of change in resistance whilst operating it. There does appear to be a bad spot. The resistance increases steadily as expected when rotated to the “open throttle” position but then at about one third “open” it appears to have a very sudden resistance drop. They are a sealed unit so a new one has been ordered from Mx5 Parts.

Hopefully the new TPS will sort it Paul - certainly the error code is very specific.

Have to say I would usually recommend replacement of the entire throttle body with all sensors for a known working used item. These are the same for all MK2/MK2.5 cars and available very cheap as do not generally give issue. 

You have the error code and what appears to be proof that the unit is faulty so much easier just to replace the TPS - hope it works, let us know.