My sons 92 Civic 1.5 has failed its MOT because of emission problems. At tickover everything is ok but when revved the CO level is too high and the lamda is low. Its had a new CAT fitted and and a new oxygen sensor, plus a 2nd hand ECU but it all makes no difference. One possible cause put to me is that he had fitted a new 4 branch performance manifold before the MOT but we are loathe to spend any more money on such an old vehicle. Its already cost more than its worth and yet he faces having to scrap a lovely motor that looks, sounds and goes like a dream. Can anyone help us?

 

Is the Check Engine Light ON? If so, what trouble code was retrieved?

 

Check engine light did not come on

 

I could be way off on this, but isn't high carbon monoxide production caused by incomplete/inefficient combustion? If so, your emission problem might be solved by doing a basic tune up (e.g., adjusting the timing and changing plugs, wires, distributor cap, rotor, air filter, etc.).

 

a good tune up should fix problem


im so glad my state has no emissions. i even run no cat.
dont junk it sell it to me lol.