Tune resistors and lambdas...

[chris1972]

My 500 is fully decatted and is running a bit rich. I noticed yesterday that my Lambdas were loose after I could smell fuel when using the rad fans in slow moving traffic, which I think has exacerbated the running rich problem. I've also noticed that my oil is a little darker than normal (I didn't do this when catted).

I've of course tightened the Lambdas again, however, I don't know whether it is just running rich generally or if it has just been caused by loose lambdas at the moment. In the long term should I be looking at changing the tune resistor to the green one whilst I'm decatted? How do I test the lambdas?

I've searched the web, but there seems to be a variety of opinions on the subject.

[Richard 858]

Not sure about how to test the lambdas (I'm still a bit of a TVR novice) but my fully decatted 450 (with Clive F's Y-piece) seems to run better on white setting as immediately cut out when starting on green setting. However Clive's reply was simply that some engines prefer to stay on white setting after decatting & some on green, doesn't seem like there's any specific reason so try both & see which one is best for you ! But again I'm no expert, still finding my way !

[blitzracing]

Stick with the white tune and lambda probes- you dont know if the green tune is sutible for your engine. As for running rich, it should not happen on the white tune unless something is wrong. User RoverGauge to check the short term lambda readings are cycling around the mid point at idle, and that the long term trim is less than 100% on both banks. Check for any fault codes as well.