Why is when i "ground" my HEGO sensor (grey wire with blue stipe) That my car runs like s**t? It is a 91 EAII converted to multi point, I have just tested all the pins i can test on ECU, The voltages are fine, except the ISC is 11.5V, instead of 11V (i think that is fine isnt it?)

But when i take the grey,blue wire off earth, leaving it free hanging my car is runs beautiful, but the ECU voltages are wrong, the gound is about 3.5V, pin 49...

what the car does, is it surges bad at constant throttle, and misses very badly on idle, leave the HEGO un grounded and it runs fine??? WTF??

Any ideas would be muchly appreciated Cheers Davo.

the hego is f**k,,if works with out it connected but not when it is then it is stuffed

get a new one

No its not, what i was saying is, when it is connected all the voltages the ECU is getting, is what they should be, according to standard's...

I will try a new one tho, just to prove me wrong...

check the voltage at pin 29,,it should have a green with blue trace wire,,thats the wire from the hego to the ecu

pin 49 is just an earth along with pins 60,40 and 20

also may be worth checking the fussible link grey with yellow trace according to my book.

and then check pin 5