Yeah, I understand that for a carb (non-CCC), but we're dealing with EFI. How can an oxygen sensor do anything useful when there's an extra stream of oxygen pumped in between the combustion chamber and the sensor?
CK5
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A.I.R system?? -have loss of power… code 43 for knock, and 44 for lean condition????
- Thread starter scouthead
- Start date
Most likely calculated, using Act, ect, and map/maf/baro sensors and diverter valve position
I don't think it can do that. First of all, the TBI ECU is pretty primitive. I also don't think the airflow calculation can be very accurate over RPM, air temp, etc. Then, you're basing the engine tuning on the exact operation of that convoluted system of vacuum valves, check valves, etc., which must vary over time and from vehicle to vehicle. The biggest problem is that you want to control AFR inside the engine and you want it to be near 14.7:1. With the air pump, your exhaust is way leaner than 14:7 and the O2 doesn't detect anything else. So when the air is pumped into the exhaust manifolds you have no idea what AFR is. You could revert to open loop whenever the diverter valve swings, but that doesn't sound like an emissions improvement.
That's why I was hypothesizing that on TBI engines, the pump is only for warmup- to get the cat hot faster. It seems like a competing goal with getting the O2 sensor hot, though, and I would think that getting to closed loop is more important than having the catalyst active.
That's why I was hypothesizing that on TBI engines, the pump is only for warmup- to get the cat hot faster. It seems like a competing goal with getting the O2 sensor hot, though, and I would think that getting to closed loop is more important than having the catalyst active.
I'll see if I can find the TBI AIR Stratagy in my manuals. It has been a long while since I needed to diagnose and TBII AIR systems
