WB O2, idle problems, etc

[unclesam099]

I just installed a WB O2 last night and I am wondering a few things.

1. My idle is at 17+ AFR. Shouldn't it be 14.7?

2. My car's low trim is pegged at 139%.

3. If I use my SAFC to add fuel in, I have to get it to 20% to get the AFR to 14.7 or get the low trim down near 110%.

4. I am running the MAFT in blow-thru with a 3" GM MAF. 450 injectors, but I want to put in 550s that I have. I'm worried, though, that this will cause more problems with being so rich at idle.

What kinda things would cause this? Also, what can I do to correct the situation? I get poor mileage around town, which is where I drive most of the time. I would like to correct this situation. Thanks.

 

[unclesam099]

Another thing I just thought of. If my stock O2 sensor is reading the same as my WB O2 at the end of the downpipe, it's not an exhaust leak... right? It's gotta be something on the intake side of things.

Are my assumptions correct so far in troubleshooting? Any advice would be helpful.

 

[tom04841]

Are you sure you have the maft set correctly? If you have to add in 20% at get 14.7, i would say that the maft is already set for the 550 which flow @ 20% more than the 450. Pop n the 550's, zero out the safc, and i bet you will be close to 100% on your trims

 

[GVR4592]

17:1 is very very lean, not rich. Check for boost/vacuum leaks, make sure you have no exhaust leaks. Double check your MAF-T settings.

 

[unclesam099]

It's only at idle, though. When cruising, it bounces between 14.3 and 15.2 or so (so 14.6 +/- .6) and I think that's normal.

The MAFT is set for 450s.