I have a Wideband Air fuel gage and have been adjusting my MPS. When I was tuning injected motorcycles I was shooting for ~12.7:1. What numbers do I want to shoot for in a 2.0L FI D-Jet runing regular fuel.
I was thinking that I want to keep the numbers setween 12:1 and 13.5:1.
I have hear that >14:1 is to lean.

12.5-13.5, for a stock engine I'd try for the 13.5:1

There is a lot of flucation in the numbers depending on speed, Vacuum and load so I was trying to keep the numbers below 14.

Only worry about the numbers under load, accelerating and cruising.
Forget about the numbers the rest of the time and idle can be a bit lean.

+1 ....... idle can be 15:1 ......

Sounds good, I'm at 13:1 at Idle (I can adjust the ECU screw and TB screw)
The rest of the time I'm between 12:1 WOT and 13.5:1 low load depending on speed and load.

I'm trying to avoid going over 14:1

is 12:1 to rich at full load and WOT?
Is staying <14:1 good?

You're good .....leave it alone.

Thanks, I started out at 14.5:1 to16:1. I think I'm done adjusting. Now I will set my back up MPS to the same numbers and check it out.

Yes that will work. however at idle there is really no reason not to be at 14.7:1. Any more rich than that and one is simply contaminating the oil quicker. The only reason to go rich to say 12.6:1 is for power. But even 13:1 is plenty rich for power. If you are pinging, then the timing needs to be adjusted. Excessive fuel dilutes cylinder wall lubrication which increases wear.

I say 12 to 1 at WOT starting at 2000rpms and it will lean out to 14 to 1 at 5500rpms. What you don't want is 15 to 1 at 5500rpms.

Avoid hanging out in the 14.7 - 15 - 15.5 zone (this is the death zone). One can go leaner when under part throttle cruise as high as 16-17 and see lower CHT's but only if your using a vacuum advance distributor. If your using a centrifugal only distributor shoot for 13.2 (+-.5) across the board.

This chart shows how CHT's and AFR & vacuum advance work. The dashed line in the middleis 14.7 stoichClick to view attachment