Lean no knock

[JDR7919]

Hello,
I installed a 3bar the other day and got it calibrated. Now my wideband is reading lean in the 12s to 13 a/r but Im not knocking. How is the possible? I zeroed out my fuel sliders and have the same result.

Any ideas?

 

[mikelv]

You might have an exhaust leak somewhere by the O2 housing. Just a small one will lean it out.
Also, does the WB go lean all the way during cruise, and come back at idle?
This is your culprit 9 out of ten times. Or a bad sensor.


And how do you know your not knocking? What boost level, what octane. Is your profile updated? Let us know, thanks.

 

[mikelv]

Ok I see you run DSMLink.
You're stock knock sensor is very sensitive, so if your not knocking, then you either have not calibrated the Bar correctly, or you got an exhaust leak.

 

[JDR7919]

Boost is about 18psi on 93 oct.

 

[need2boostpsi]

yeah i had the same problem, turned out to be a pinhole by my WB. i was still running lean but not in the 12's like my WB was saying.

 

[JDR7919]

yeah i had the same problem, turned out to be a pinhole by my WB. i was still running lean but not in the 12's like my WB was saying.

Do you mean a hole in the exhaust or the sensor? How did you fix?

 

[mikelv]

Do you mean a hole in the exhaust or the sensor? How did you fix?

It's a hole in your exhaust man. If the sensor had holes in it, it wouldn't work. Just get up under the car while it's running and see if you got yourself a leak.

If you're mounted right after the O2, then it's probably your DP Gasket, or the O2 housing itself. You might just have some exhaust bolts that rattled loose.

Check it out and let us know.

 

[JayRolla]

Remember usually an exhaust leak (small one) will only cause a bad reading at idle, because the exhaust is acting like a vacuum. When under throttle it doesnt really suck much air through the leak.

 

[mikelv]

Remember usually an exhaust leak (small one) will only cause a bad reading at idle, because the exhaust is acting like a vacuum. When under throttle it doesnt really suck much air through the leak.

At idle, at least on an AEM, will go totally lean, and cruise it'll just be leaner, same with WOT.

Depending on the leak really, like you say. He'll just have to get under the car and find out.

 

[Rob10_99]

How old is your knock sensor? Has it puked its guts yet?

 

[mikelv]

Any update??

 

[JDR7919]

Nope! I had a axle go out on me and have not had a chance to replace it.

 

[JDR7919]

I have tried looking but have not found any. I got under the car and could not hear or feel any.
I even ran some seafoam through it to see if that would show any.
Whats the best way to find leaks?

 

[mikelv]

I have tried looking but have not found any. I got under the car and could not hear or feel any.
I even ran some seafoam through it to see if that would show any.
Whats the best way to find leaks?

Well, it's hard to say?
I usually can just locate them by ear, and if it's not seriously obvious then most likely don’t have that problem.
You could take the car to an exhaust shop where they will usually to an estimate for free. Just tell them you’re think you hear a leak or something, just don’t let them work on it.

If you can totally eliminate the possibility of the exhaust leaking, then we can go from there.