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Idle AFR is normally 14.7:1.

If your car is set-up with a closed loop system for injector duration and you are showing 14.2, you may have a fouled plug

Lumpy idle also suggests you may have a plug out
 

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Thanks for the replies, it's always been a bit lumpy on idle. If it were a fouled plug would that not give you a richer mix? It seems to be fine when you give if more fuel but the AFR is low (11 ish)
I've got o2 feedback on closed loop so yeh I'd have thought it would try and correct itself but it doesn't.
 

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14.2:1 is richer than 14.7:1, so I think we agree that you are potentially showings signs of a fouled plug.

Suggest you pull the plugs to see what they tell you.
 

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You say you can adjust the injector %, so Im assuming you have an aftermarket fuel controller? Getting a smooth idle is always tricky. Rich mixtures does help, but be aware that the plugs dont like it to rich on idle.

I would aim for 14.7 to begin with if I were you. It should idle fine, but you should aim for 20* timing at idle - Not only in your ignition tables, but also confirmed by a timing light. If you run MAF you should look for vac leaks if the idle is still not behaving.




PS

Fouled plugs that does not fire turns that cylinder into an airpump. This leans the measured mixture dramaticly. If you then compensate with more fuel to run 14.7:1 you will be dumping huge amounts of fuel into the cylinders. Always make sure all cylinders are firing with a strong spark, have solid compression ratios etc etc before tuning idle AFR.
 

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My 33 idles lumpy (standard cams so no excuse) the AFR was 14.2 on idle which I thought was optimum. The only way I can smooth it out is by adjusting injector %. It's now nice and smooth but AFR is more like 11. Is this normal on the RB? :tard:
Not at all. That suggests there is either a fuel delivery issue (ie, blocked injector) or there could be some kind of air leak between the plenum and one (or more) of the cylinders... either way meaning that while you are reading 14.2 AFR at the exhaust, you may actually have something going on where 5 of the cylinders are all getting say 13.8:1 but one may be getting 16:1 - bringing the average up to 14.2.
 
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