running/idling lean and lumphy idle

[Mr.Salas]

Hi guys i am trying the figure out what is going on with my car.
car is idling / running really lean 19 ish a/r.
And idling really lumpy like it has cams but there's no power hehe.

Dont know what to do. No check engine light and no faults.


Help?!!?

Thanks
chris

[Nick Mann]

Got evo scan?
I'd start by checking fuel components. Have you got any after market parts on there? An fpr maybe?

[rajvr497]

Start by trying another fuel pump.

[Mr.Salas]

Yups i have fpr. Prssure is good. 45 psi.

Yes i have evoscan.
Checked everything already. It might be that maybe due to lack of knowledge i am missing something.
Oxigen sensor is measuring 0.05 volts and does vary.

[Nick Mann]

Does vary to what? It should vary either side of 0.5V, not 0.05V.

[Davezj]

i would say air/vacuum leak small one that masses up afr on idle but due to positive boost when driving the issue is masked.
boost leak test needed to confirm.

[Mr.Salas]

Does vary to what? It should vary either side of 0.5V, not 0.05V.

Well it idles at 0.05V and if i give a little gas it goes up to 0.6 ish, but drops to 0.05 ish volts. I know the signal voltage needs to be between 0.5 to 1 volt.
So this was my first assumption that the O2 sensor is bad, but there's no faults.
So, i want to know before buying a new O2 sensor, that the one installed is bad.

[Mr.Salas]

i would say air/vacuum leak small one that masses up afr on idle but due to positive boost when driving the issue is masked.
boost leak test needed to confirm.

I am going to check for vacuum leak. I know if there is a vacuum leak the car would run rough, but right now it is idling pretty bad.
Like i said a/r is in the range of 19/20 ish and by giving a little gas varies up to 14.5, but than back to 19/20 ish.
The engine idles, but if you try putting the AC on, it will stall.

Tomorrow i will go further with my research.

[Davezj]

I had this a few days ago and it was the pipe going to the PVC valve had split and it showed the same issue as you describe.
This is why I mentioned it.
Hope it is just a pipe.

[Nick Mann]

It sounds like the sensor is working. 0.6v should be slightly rich, 14.5afr could well be right. 0.05v should be lean, which your car is. So if the car is running lean on idle and the lambda sensor is saying lean then something else is at fault.