Stoichoimetric @ WOT

[morpheus-msp]

I was driving to work this morning when I realized my A/F was leaning down to stoichoimetric around 5500-6000 rpm sometimes when I floor the gaz ? I'm pretty sure it wasn't leaning that way before !

My current setup is stock boost (5psi), NGK colder plugs and an Injen CAI.

Someone ever had the same problem or know how to fix it ???

 

[Yay-Boost]

At stock boost the colder plugs are a bad idea. The car runs very rich and will foul out the stock plugs. If you run colder plugs it will foul them out even faster. As for leaning out at higher RPM's I'm not sure usually at that RPM it will off the chart rich.

 

[mspdfreak]

Take out the colder plugs...

 

[changedman]

u have a wideband?

 

[mazdaowner123]

narrowband a/f = teh lightsh0w.

 

[morpheus-msp]

u have a wideband?

Unfortnatly not, but this is not the case, I never seen the a/f leaning out @ WOT ever in the past?? I've been running this setup for more than a year now without any problems and a rich a/f @ WOT!?

BTW, the boost seams to be perfectly stable so I rejected vaccum line leaks. Maybe a bad MAF, Temp or O2 sensor that mess the ECU.

To be continued...

 

[morpheus-msp]

narrowband a/f = teh lightsh0w.

Useless post...

I want to fix this issue ASAP so please post usefull comments or questions!

 

[Yay-Boost]

A bad 02 sensor would make sense. Have you double checked the wire you spliced into the o2 or ecu? Check the simple cheap stuff first.

 

[low_psi]

Useless post...

I want to fix this issue ASAP so please post usefull comments or questions!

but brian's right. no matter if you've seen a narrow band act like that before or not, you still don't know jack until you've looked at a wideband reading. find a wideband to hookup to your car or just go get dyno'd so you can see what the hell is going on in your motor.

like others have said, change your plugs back to stock too.

 

[mazdaowner123]

Useless post...

I want to fix this issue ASAP so please post usefull comments or questions!

K how about this:

A narrowband air fuel gauge is useless. Hook up to a wideband o2 and see what your a/f's really are, and then you'll really know what's going on.

~brian

 

[BlkZoomZoom]

Unfortnatly not, but this is not the case, I never seen the a/f leaning out @ WOT ever in the past?? I've been running this setup for more than a year now without any problems and a rich a/f @ WOT!?

BTW, the boost seams to be perfectly stable so I rejected vaccum line leaks. Maybe a bad MAF, Temp or O2 sensor that mess the ECU.

To be continued...

I would not trust anything a narrowband "lightshow" read. Period. Your PCM monitiors fuel trims very closely. If you don't have a check engine light on, then guess what? Your Fuel Trims are NORMAL. Leave it alone.

There are ssoo many reasons that the stupid a/f gauge would show off readings its not even funny. Again, leave it alone.

 

[morpheus-msp]

My only point is that it use to be rich to the max... And now, it is not ! Even if it is nothing else than a "lightshow" to many of you, there's a big difference in the reading anyway. With a wideband, I would only be able to tell you some numbers that would prove the fact my A/F is leaning at WOT, which is totaly abnormal for our ECU...

 

[DSMConvert]

impossible, your ecu would not let that happen without throwing a code...this is coming from someone who builds AFCs....little known fact is that the narrow band a/f gauges are also affected by heat radiation...ie sparkplug wire shielding starting to fall apart, stereo interference....like blk said the ecu monitors short terms way to close for a big jump like that to happen...

 

[low_psi]

You can hookup a wideband or you can keep relying on your danceparty9000 gauge...

 

[jeffmsp]

1.pay $20 to put your car on a dyno and be done with it already. the car cost many $20 bills so i know u have an extra one hanging around! post your results back here so we can see.
2. Give the narrowband gauge to ure little brother/sister for his bicycle.
3. Put those stock plugs (or copper ones with the same heatrange) back in until you start running 9+psi.
4. keep enjoying the MS

 

[mazdaowner123]

danceparty9000 lmao marc.

 

[low_psi]

you know it