Hi , i have rebuilt my mx5 mk1 eunos 1989 and i’m having problems starting the car. The engine turns over ok but fails fire but when i put a connection across gnd and ten in the ecu it fires up ok.Does this connection bypass something?
Connecting TEN and GND bypasses ECU control of the idling - normally done to adjust base idle. Never heard of anyone getting over a starting problem by doing this before:-)
Have you run a diagnostic on the car - could be the ISCV?
Idle screw isn’t wound fully in is it?
no its not wound in.
I’ve ran a diagnostic and nothing came up.
Did the light come on for a few seconds and go out? If so all fine there.
As far as I am aware connecting TEN and GND only bypasses some ECU function. Not 100% sure but reasonably confident that no potentially faulty relays for example would be bypassed to facilitate the car starting.
Only suggestion beyond that is to try another B63H ecu - very cheap to buy or someone may have one to loan you.
If you were near me in deepest darkest South Devon be happy to try a few things out.
Other than that I can only suggest entire throttle body and all associated sensors - nuisance to change and something tells me this is not your problem.
Thanks for the ideas. I have new sensors etc so i will try the ecu idea.