misfire/hesitation/dead spot at low rpm, help

[zo6vette]

2009 zo6 twin turbo, makes about 1100 rwhp, i am having bucking surging issues that im working on but now i have noticed while cruising at lower rpm about 2200-2500 feels like there is a misfire or like it's cutting out at that certain rpm range, also i can hear what appears to be a slight backfire or a pop sound, so im now leaning towards rather than a buck or surge it's cutting out like an ignition issue, any ideas? here is a datalog im very new at this so not sure as to what im looking at, also car is SD tuned so i believe on the scanner it does not show misfire.

[kevin87turbot]

The Drivers Side O2 sensor is showing to be really rich throughout the log. You'll have to determine the cause of that. It may be leaky injectors on that bank, or simply a bad O2 sensor.

[zo6vette]

ok ill have to look into that.

[Scottgt21]

If he's having an ignition related misfire, wouldn't the o2 sensors still read rich on the related bank?

[kevin87turbot]

If he's having an ignition related misfire, wouldn't the o2 sensors still read rich on the related bank?

They will actually read lean if he's having a misfire on that bank. Think of it like this...the oxygen sensor senses oxygen in the exhaust. If you have a misfire, then there will be a lot of oxygen in the exhaust, so it shows up as a lean condition.

[zo6vette]

so today for the hell of it i smoked tested exhaust, thought i heard a leak but its ok, smoke tested for vacuum leaks all ok, checked blow off valve was working as it should and it is, checked all plug wires with ohm meter wires checked out ok, pulled a few plugs they look ok gap was .025 ngkb8efs, still need to pull all of them to be sure, i guess next ill pull the fuel rail and check for injector leaking, and do a coilpack test, any other ideas?

[jsf55]

Just jumping in with something I noticed, your logging knock, but there's no spark retard figures ? ant the IAT is reading very low all the time

[zo6vette]

Just jumping in with something I noticed, your logging knock, but there's no spark retard figures ? ant the IAT is reading very low all the time

I will look into that as well

[Scottgt21]

I see. It makes sense if not much of the fuel being injected makes its way out of the exhaust valve into the exhaust stream. Before I was thinking that raw fuel exiting the exhaust valve would make the sensor read richer

[bmd2_colo]

IAT 2 is the post-compressed air, in the intake manifold, right? I could see some fueling be off if that somehow is reading 32F all the time. I'm not up to speed on C6s tho. I'd take a look at the sensor before anything else? If it surges at low rpm as well (idle-1.5k), you might need to check out the injector timing stuff and make some adjustments for the cam, etc,etc. As scottgt21 was saying. That being said you shouldn't have too much overlap (if any?) if your cam is spec'd for the turbo build blah blah blah. no need to worry about the false lean created by the whole short circuiting thing. Been mentioned- O2 #1 looks like its misbehaving with the voltage activity, also, fwiw. That being said, if its bucking and surging at low rpm, I'd take a look at imjector timing if it were me. Once the other stuff got fixed

[zo6vette]

IAT 2 is the post-compressed air, in the intake manifold, right? I could see some fueling be off if that somehow is reading 32F all the time. I'm not up to speed on C6s tho. I'd take a look at the sensor before anything else? If it surges at low rpm as well (idle-1.5k), you might need to check out the injector timing stuff and make some adjustments for the cam, etc,etc. As scottgt21 was saying. That being said you shouldn't have too much overlap (if any?) if your cam is spec'd for the turbo build blah blah blah. no need to worry about the false lean created by the whole short circuiting thing. Been mentioned- O2 #1 looks like its misbehaving with the voltage activity, also, fwiw. That being said, if its bucking and surging at low rpm, I'd take a look at imjector timing if it were me. Once the other stuff got fixed

I will also check that as well