402 LS2 L92 top end stuttering/down on power. Inj or valvetrain issue?
07-18-2011, 08:10 PM
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402 LS2 L92 top end stuttering/down on power. Inj or valvetrain issue? Drove the car yesterday with no issues; idled and ran completely normal.
Started up today and it is hesitating when leaving a stop and almost feels/sounds like I'm firing only half the motor.
No codes being thrown.
WB in drivers side going super lean.
LTFT's showing -15.6% on drivers side but -1.3 passenger side when cruising.
First time I've seen Inj Duty cycle off from side to; as much as a 3% difference eg. 2% on one and 5% on the other.
IAC's showing ~110ish; last week they were 30's at warm idle.
My first thought was valve spring but there is no extra noise from the motor and I'm not getting a misfire or any other code.
My buddy thought Inj fuse but they were fine.
He thinks maybe lifter or rocker; BUT he still thinks it's Inj related because of the Duty Cycle/Lterm/WB difference.
Any ideas?
Started up today and it is hesitating when leaving a stop and almost feels/sounds like I'm firing only half the motor.
No codes being thrown.
WB in drivers side going super lean.
LTFT's showing -15.6% on drivers side but -1.3 passenger side when cruising.
First time I've seen Inj Duty cycle off from side to; as much as a 3% difference eg. 2% on one and 5% on the other.
IAC's showing ~110ish; last week they were 30's at warm idle.
My first thought was valve spring but there is no extra noise from the motor and I'm not getting a misfire or any other code.
My buddy thought Inj fuse but they were fine.
He thinks maybe lifter or rocker; BUT he still thinks it's Inj related because of the Duty Cycle/Lterm/WB difference.
Any ideas?
07-18-2011, 10:04 PM
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Check those o2 sensors.
Swap banks see if it shows the same trend.
Same with coil packs.
Tip in Hesitation and stumble could be from overly rich or lean fuel.
Swap banks see if it shows the same trend.
Same with coil packs.
Tip in Hesitation and stumble could be from overly rich or lean fuel.
07-18-2011, 11:22 PM
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You miiiiiight be onto something 
I just looked at the log; drivers side O2 Sensor STATIC at 1.107
I've never seen an O2 sensor fail to the point where it doesn't move
Wish I would've looked at the O2's in the log earlier. I could have went to the Autoparts store and got a pair. Hopefully that's all that's wrong.
I'll update tomorrow. Thanks guys!!!
I just looked at the log; drivers side O2 Sensor STATIC at 1.107
I've never seen an O2 sensor fail to the point where it doesn't move
Wish I would've looked at the O2's in the log earlier. I could have went to the Autoparts store and got a pair. Hopefully that's all that's wrong.
I'll update tomorrow. Thanks guys!!!
07-19-2011, 06:53 PM
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O2 sensors replaced and problem solved.
Since I'm running the car with just a pair of O2 sensors and air temperature it makes sense that a sensor failure will cause a LOT of issues lol.
Side NOTE: the guys at my exhaust shop are all import Honda/Toyota tuners.
After driving my car around for a while they fell in love with the "smoothness, immediate response, and how daily-driver friendly it is."
2 of the mechanics are dumping off their import race cars and looking for LS1's
Since I'm running the car with just a pair of O2 sensors and air temperature it makes sense that a sensor failure will cause a LOT of issues lol.
Side NOTE: the guys at my exhaust shop are all import Honda/Toyota tuners.
After driving my car around for a while they fell in love with the "smoothness, immediate response, and how daily-driver friendly it is."
2 of the mechanics are dumping off their import race cars and looking for LS1's
