First step would be checking the fuel pressure. I know you've tried checking different widebands, but where is the sensor mounted, could there be an air leak near it? I suppose after that you need to consider getting your injectors tested.

 

The o2 sensor is located in the mid pipe about 1ft after the test pipe. There is a stock 02 sensor located at the same angle about 2 inches in front of it, I will try switching them to make sure that the stock 02 sensor is not blocking air to the wideband. Also would an exhaust leak matter at WOT, as far as getting accurate AFR readings.

I gotta find a fuel pressure gauge and then I can see whats what.

 

if you have an exhaust leak, it causes the sensor to read lean...so that could be it.

However, you can usually tell when you have an exhaust leak. It's loud.

 

That is the problem with putting a wideband sensor after the DP. If you have a leak at the DP / Cat junction you can get inaccurate readings with the wideband. Having the wideband in the DP close to 12 o'clock lessens the chances of this happening.

 

I know we don't go off narrowband O2 readings for good reason, but for what its worth yours is showing a higher voltage than mine is... yet my wideband says I'm running richer.

 

I don't think I have an exhaust leak, the car does not sound like, if there is a leak it would be very very tiny.

Don't bother looking at my 02 voltage, I have a non-fouler on the sensor so it does not throw a code.

 

Have any of you installed a fuel pressure gauge?

How do you do it.

 

You have a spark plug fouler on the first 02 ?? Or do you mean the 2nd 02.

Your O2 logs should be from your first 02 not the 2nd.
.

 

o ok, yea the fouler is on the second 02 sensor.

Stock widebands are useless though.

 

Yeah, the stock narrowbands aren't very good for tuning, but not completely worthless

If you find that your fuel pressure is getting low, it may be a clogged fuel filter.

 

I don't see how my filter could be clogged - I have 6,000 miles on the car.

What do you guys see for you AFR at idle?

 

It will try to maintain stoic, 14.7:1, so it will be bouncing around 14 to 15.2 or so.

 

Generally, the idea is simply to put in a sensor or gauge inline with the fuel line.

I don't have any experience with this fuel system but the concept is the same on all cars.

You can get T fitting and send one end to your sensor/gauge.

 

I'm just glad to know the stock fuel system with a walbro will be sufficient for 380hp (dll dyno) .

 

I suspect I may have an exhaust leak because my AFR at idle is 16 on the wideband. What is the 02 voltage supposed to be at idle?

I think a small leak may throw off my AFR readings slightly about 1.5 at idle and maybe .5 or so at WOT.