Ideal Ignition Timing 3.9 EFi Non Cat

jimbob · Post by **jimbob** » Thu Feb 14, 2013 6:52 pm

Gents,

looking for the base timing the rover manual states 4 BTDC, but at present I'm running 8 BTDC, with a tornado chip, on a 3.9 efi non cat Discovery.

I've a slight miss at idle, i suspect its a weak plug.

Its no rocket ship, but would love to get it sorted.

jim

countrymansouth · Post by **countrymansouth** » Sat Mar 16, 2013 8:53 pm

Replace plugs, check leads, clean coil, cap. Lossen dizzy slightly set timing to 6 degrees BTDC factory default. test drive up steep hill low revs to high. Keep doing test, each time advancing timing 2 degrees untill it pinks, then retard 2 degrees and test. If ok tighten dizzy clamp, you have set timing for that particular engine. Personally I run on 97ron petrol engine runs well.

Robrover · Post by **Robrover** » Tue Mar 19, 2013 9:46 pm

The factory setting is very conservative. I run 12 degrees static and it seems to go a bit better without pinging on 95 or 98 fuel.

sidecar · Post by **sidecar** » Tue Mar 19, 2013 10:05 pm

Robrover wrote:The factory setting is very conservative. I run 12 degrees static and it seems to go a bit better without pinging on 95 or 98 fuel.

I agree that the factory setting is not all that good. 12 degrees will give a good boost in BHP low down in the rev range and the top end can improve if the current 'all in' figure is low.

An important check would be to also check that the all in figure is not too high when you reset the timing, 32-34 being OK for a 3.9 lump. If the figure is too high the dizzy can be modified to 'peg it back' to the required amount.