I have been running the b18c in my eg hatch now for about 3 months. All i have done is a walbro 355lph fuel pump, cold air intake, and b&m regulator. At high rpms the air fuel gauge goes lean and I kind of feel the car hesitate a little. And every once and a while if im cruising the car would kind of hesitate for a couple of seconds and then stop. Any ideas?

 

You have a 355lph fuel pump?!? You mean 255 right? And why?

Do you have wideband? How do you know your going lean?

Go back to stock fuel pump or get it tuned.

 

yeah i meant 255lph. Im using the air fuel gauge.

 

reg O2 sensor or wideband?

 

regular o2

 

since the stock o2 sensor only sends a 0-1v signal to the ecu and the wideband would send a 0-5v signal, the stock sensor doesn't have the capability to tell the computer if the mixture is rich or lean. it just compensates for the numbers that its given.

Cliff notes: wideband= accurate.
Stock 0-1v sensor= not accurate for tuning.

 

yeah the stock sensor only gives a general idea, if you were truly running dangerously lean you would throw a code

 

but sometimes if im flying on the highway it will throw a check engine but if I turn the car off and then start it back up it will go away.

 

have you ever checked the code?

 

by the time I checked the code it was cleared

 

That doesnt make sense. They don't clear themselves.

Do you know how to check codes?

It sounds like your O2 sensor isn't working properly.

 

couple things ... b&m can cause this, noticed it quite a few times on customer cars.
second, don;t discount your standard O2 readings, they are fairly acurate in the 14.7:1 stoic range ... so if its reading in that range then yes its lean.

greg

 

Couple of things. First, the code is not cleared, it just isnt throwing the CEL. Most likely the knock sensor. This doesn't necessarily mean the motor is knocking, the sensor could be bad. If it is not the knock sensor, it could be the o2 sensor. Typically the o2 sensor will throw the cel within a few minutes after the engine is turned over. I've driven 500 miles before without the cel coming on for the knock sensor, but when I jump the ecu, it reads code 23.

Basically, loop the ecu, and read the cel. It will still put out a number if what is happening you are saying is true.

Second, depending on what a/f range you are in (14-15:1) your stock o2 sensor is accurate enough. When TUNING you will definately want a wideband.

 

I jumped the ecu and the check engine just stays on while the jumper is in. But if its running lean I was thinking it was a faulty fuel pump.I have a rev hard kit that I will be installing soon and I just want everything to be right before I install it. I ordered a str fuel rail,RC440s,ARp headstuds, and a ac blockgaurd.

 

So during a tune, one should use a wideband o2 sensor to see optimal results. But, after the tune is it safe to put back the stock o2 for daily driving and longetivity?

 

so how much can I pick one up for?