reduce emissions

[flyerncle]

O2 sensor 1 in manifold controls fuel in relation to rear O2 sensor,ect switch also controls fuel in relation to temp,so possibly ect switch is faulty.

[Wain]

I think we might be onto something with the ECT sensor, after we did the emissions test the engine was very hot as expected but then cut out after back firing a bit. It starts fine now its cool so can only assume it over heated, water pipes were warm but not as hot as i expected. Maybe the sensor is ok but an issue with the coolant not circulating?

[flyerncle]

Run engine with return to header tank off and make sure you have a good flow to tank,if not you have flow/circulation problem or stat is playing up.

[Wain]

Ah so a cooling issue is causing the high emissions? I will take a better look at the cooling system at weekend in that case!

[flyerncle]

Yes and No,if you have flow problem its possible there is no liquid around sensor and it wont read properly and will compensate to keep within pre programmed limits allegedly.
Wont do head gasket a lot of good either and O2 goes high when it pops due to burning the water.