im having a major problem with my car i dont know if its the o2 or what. But when im driving an it starts to get warm my o2 starts to read around 13.6 to 14.0... its not a wide bands its a apexi turbo timer. an i have a hks fcon with a fcd. The motor only has 110 miles on it with a medium streetport... i have the fcon set at 4 an my motor runs fine till i let off the gas an then it goes right to 20.0. i checked my tps an its fine might be outa ajustment... would having stock injectors on a ported motor do this...

 

Look at the jpg and DECELERATION DECREASE. Fuel is cut from one or both rotors during deceleration. TPS/boost/pressure sensors involved.

 

Not too mention that narrow band O2 sensor is far from accurate.

 

Deceleration enleanment is normal. Ignoring the AFR reading, does everything else seem OK during deceleration? If so, then I wouldn't worry about it.

You should have a local tuner help you out with things like this. Everybody needs to start somewhere, but it's not such a good idea to try tuning on your own with only the internet as a guide.

It is accurate enough for a good tuner to use. He would have misdiagnosed the reading even with a wideband AFR meter. It goes to show that an AFR meter does not make up for education and experience, and it is not necessarily a good instrument to rely on for accurate tuning.

 

Whatever you say.. The resolution in the ramp up area isnt near good enough for me to trust for any real accurate measurements.

 

I totally agree. Most novices do not know how to use a narrow-band AFR meter, as evidenced by the subject of this thread.

Anyway, no AFR meter will allow for total tuning of the engine. It is simply a tool to help with some aspects of tuning.

 

im no novice lol well yea i know that a narrow band a/f wont give me a good reading but it still helped me know that i was leaning out during decel. as for how it seem its ok it kinda sounds a little wierd but as soon as i get on the gas its normal. it might just be cause im still learning the sounds of street port over the stock port. if that makes any sence

 

Lean under decel is NORMAL. It's how the EFI system is supposed to operate.

 

^ what aaron cake said. it's something pretty much every stock car does to save fuel, why should it be pumping any fuel into the engine if the throttle is closed?

 

It does what is printed on the attached jpg says.

And it's one of the few things the TPS is actually responsible for. Misrigged TPS........scews up the fuel cut.

 

yea i adjusted my tps the other day an it helped alot not it only does it when i let all the way off the throttle im still in break in thought so it was just a scary thing for me to see