Lambda Sensors... Do I need them??

[thenick]

Hi all,

I'm currently in the process of fully decatting my 450 Chim so it will be left straight through with ACT cherry bombs

Whilst spending another afternoon fighting with rather unwilling bolts, my attention turned to the lambda sensors. I have to take them out obviously (which i'm still unsure how to do really...!), but do I need to put them back in? I ask this because I noticed that Wildfire doesn't have any (he has a 4.0l precat griff with full ACT exhaust from manifolds back as I am currently putting on). Where the lambda sensors should screw in he simply has two shiny bolts to block the holes. Why is this? And seeing as I should have the same exhaust system as him in a couple of days, can I leave mine out as well?

Nick

[Cider Andy]

If it has a standard ECU (Lucas 14CUX) with the original chip, it will contain two maps, selectable by the 'tune resistor'. I think if you fit the non-cat tune resistor (one's white, the other green, can't remember which is which, but you need the one you don't have!) you won't need the lambda sensors.

Cutting a slot in an old box spanner will enable you to remove the lambda sensors without having to cut the wires off them. If you can't get enough purchase on the spanner after cutting the slot, put a jubilee clip around it once it's on the sensor.

[thenick]

Ah nice one, so no lambda sensors... I just did a little research on the net and it seems to say that the sensor is only for adjusting the fuel/air mixture very slightly to keep the cats within the close limits of their operating temperature to make them effective. This shouldn't matter if I just remove them then as there are no cats to adjust for.

Regarding the tune resistor, I spoke to Tim (ACT) about needing one and he said I don't need to change it. Apparently all it does is reduce the fueling very slightly due to the cats needing a bit more to keep them hot and working. This means that once the new bits are on it will overfuel very slightly but I don't really mind as firstly this will give more pops bangs and flames, and secondly I'm fitting a Tornado chip in the next week or so, so the fueling will be sorted out then.

[chef_golf]

I have decatted my 4.3, i had stainless manifolds made and a stright through exhaust, i got a mark addams chip and a new tune resistor which is to replace the one for the cats, runs sweet and wakes the dead

[spend]

I can assure that car runs fine with lambda sensors & no obstructions (just too fin loud IMHO). I did try puttinga different resistor in & couldn't really notice any difference (430).

Dave