Lean on deceleration

[alkadaypx182]

When I let go of the gas pedal and let the car decelerate my wideband tells me that I am running lean. Also when I let go of the gas and push in the clutch my rpm's drop to nearly zero and the wideband goes from going rich to lean and then after having a bumpy idle for a second it goes back to normal. Can anyone help me figure this out?

 

[Xplicit93AWD]

The only thing i can think of is. On your SAFC II on your low setting put the trims starting from idle a little bit richer and move on from there. Hope this helps, keep us posted.

 

[alkadaypx182]

Aren't the trims on the s-afc only for accelerating? I also forgot to mention that while the car is decelerating the vacuum goes down to about 23 inhg. Don't know if that means anything.

 

[1LE]

It all sounds normal to me (or if not "normal", it's what my car has always done)

 

[GVR4592]

It is perfectly normal for the WB to say lean under deceleration. If you look at your IDC or injector pulsewidth under decleration you will see they are 0. The vacuum going to 23 is normal as well.

There is a lot of info on this site about the car dying/trying to die when the clutch is depressed. There a few things that can cause it.

 

[candela]

exactly what GVR4 said

 

[Dragon Talon]

What about running to lean. when the gas pedal is floored. I have had a promblem running lean for awhile. I have new vacuum lines, re sealed my whole exhust system, semi-new o2 sensor. and stock gap spark plugs. The engine was running fine intill 1 day i advanced my timing 2 degrees to get a faster E/T. I tuned up the car, change alot of stuff. and the car is still running lean when i floor it...

 

[GVR4592]

What A/F ratio are you seeing at wot?

 

[Dragon Talon]

I have a A/F meter that has lines on it. Meaning it does not read by volt's or #'s...... But when I'm WOT the needle goes to 2- 2 1/2 notches before it is maxed rich.. Before hand the needle would go all the way up and max out rich. It is a noticeable difference in power..

 

[spyderturbo007]

I have a A/F meter that has lines on it. Meaning it does not read by volt's or #'s...... But when I'm WOT the needle goes to 2- 2 1/2 notches before it is maxed rich.. Before hand the needle would go all the way up and max out rich. It is a noticeable difference in power..

I am guessing that you are not talking about a WBO2. Is this one of those gauges that taps into your stock O2 sensor?

 

[steve]

When I let go of the gas pedal and let the car decelerate my wideband tells me that I am running lean. Also when I let go of the gas and push in the clutch my rpm's drop to nearly zero and the wideband goes from going rich to lean and then after having a bumpy idle for a second it goes back to normal. Can anyone help me figure this out?

The ECU turns off fuel during deceleration. That part is normal.
Your RPMs dropping to nearly 0 isn't. The ECU should use the ISC as a dashpot and catch this. People with lightened flywheels seem to have this problem even when everything else is 100% correct.

Steve

 

[92GSXBaltimore]

is you cbv/bov vented?

 

[Flip_4G63]

The ECU turns off fuel during decelleration. That part is normal.
Your RPMs dropping to nearly 0 isn't. The ECU should use the ISC as a dashpot and catch this. People with lightened flywheels seem to have this problem even when everything else is 100% correct.

Steve

Agree.

My car ran fine till i put the Fidanza in then i had to catch the RPM's before it killed the car.

 

[ginsu417]

Venting your diverter valve to atmosphere would attribute to the car dying on decel, but a vented diverter valve after the airflow sensor should show up on a wideband as a rich condition (at least between shifts). The description of the symptoms is a bit fuzzy tho.

 

[ltho98]

When I let go of the gas pedal and let the car decelerate my wideband tells me that I am running lean. Also when I let go of the gas and push in the clutch my rpm's drop to nearly zero and the wideband goes from going rich to lean and then after having a bumpy idle for a second it goes back to normal. Can anyone help me figure this out?

The injectors are supposed to shut off when you let off on the gas. It recatches for idle right around 1500 or so. Increase your low throttle settings up a hair and it should be ok.

 

[Dragon Talon]

I am guessing that you are not talking about a WBO2. Is this one of those gauges that taps into your stock O2 sensor?

My A/F meter is hooked up to my Ecu, maybe the o2 sensor line.Its a basic A/F meter..

 

[steve]

My A/F meter is hooked up to my Ecu, maybe the o2 sensor line.Its a basic A/F meter..

Your A/F meter is attached to the narrowband O2 sensor the the ECU uses for closed loop operation.

Steve

 

[alkadaypx182]

The bov is vented back into the intake. The day I vent to the atmosphere is the day I sell out. Thanks for all the help so far.

 

[Dragon Talon]

Your A/F meter is attached to the narrowband O2 sensor the the ECU uses for closed loop operation.

Steve

Is that a bad thing? Also my O2 sensor only goes to 2 of the exhaust output not all 4.. and I have aftermarket Pace setter headers...