4.0L Pre-cat running very rich at idle?

[dwgriffith]

Changed the afm and it seems a bit better but still not right. The car has been tornado chipped and rolling road setup by mark adams, piper 285 cam, engine ported and balanced, larger valves, everything else more or less standard. Apart from the obvious setting on the afm from the ballpark 1.5volts is there anything else I should be checking/adjusting? eg The fuel regulator maybe not reducing the rail pressure at idle? etc etc

[steve-V8s]

Is this an MOT problem ? I had the same issue with the V8s, which I guess had the same engine (but un modified). I carefully went round the sensors, borrowed and swapped the AFM and ECU to no avail. I also blamed the fuel regulator but changing it made no difference.

Other than MOT time it was fine so at test time I replaced the air bypass pipe ( goes to the stepper motor port) with a piece fitted with a valve open to atmosphere. I could then adjust the valve to let in un metered air and lean it up at tick over. After the test I simply put the original pipe back.

[AntonyJ]

Does it/you smell of hydrocarbons?

Could also be the injectors needing a clean, if they aren't "spraying" properly there could be unburnt fuel coming through..

[dwgriffith]

If you go near the pipe to get a good sniff at it were the fumes are strong enough to make your eyes start watering, so I guess so?