KraZy

iTrader: (4)

Would this be causing me misfires?

I installed (well Blown SS installed) my LC1 wideband and its showing ~17 AFR when I am cruising at 60mph, then I feel the car jerk......I want to say misfire. Then I see it richen up to about 13.5

Is this a tune issue, or a mechanical issue. I am due for a tune this week and I'd rather not take the car in for a tune if theres something I need to fix. The car runs great the rest of the time and stays 14.7 to 15.0 unless I give it enough gas to get into boost then I run ~10.5AFR.

Any input is greatly appeciated!

xaon

iTrader: (12)

sounds like a tuning issue to me. And yes, too high of an AFR will make the car buckle like that.

KraZy

iTrader: (4)

whheewwww

Thanks man!!! Its scary seeing that guage hit 17 just cruising along.

87calais

Lean cruise enabled?, if so,m leave that ****, and enjoy the increased fuel economy

KraZy

iTrader: (4)

Is this a feature of the PCM??

Its causing the car to buck.

SmokingWS6

iTrader: (1)

Highly doubt its lean curise. Sounds like something tuning related is out of wack, or perhaps your o2's are going dead

ringram

Stock Oz PCM's run lean cruise into the 17's.
Word is to go high 15's at best, so many richen up a little.
Bottom line its your tune, if its deliberately that lean, then try a little richer at cruise.

wicked_95z

iTrader: (8)

Could running that lean cause detonation and the bucking

xaon

iTrader: (12)

yes, it can.

KraZy

iTrader: (4)

I just want to make sure this is a tune issue not a mechanical issue. The car goes in for a tune this week.

I am still running a procharger tune on the turbo........the most boost I see is 2lbs right now and its 10.0afr while boosted.

Yelo

True...but he's in North Carolina, and I doubt he's got an Australian Holden PCM under the hood (I could be wrong though)

oange ss

iTrader: (50)

no lean cruise mode in American PCM's.....lean reading could also mean on the verge of or getting into a lean misfire....find out which cell is causin it and reduce spark a couple degrees or richen that cell up with fuel

ZL1Killa

iTrader: (17)

hey man, i'm in wilson, Nc.

wicked_95z

iTrader: (8)

None of us have any tuning software for the LS1 but I see what you are saying

ZL1Killa

iTrader: (17)

i have tuning software and i'm located in wilson, nc

ringram

Reason I mention Lean Cruise is because there obviously isnt any reason why you shouldnt or cant run that lean as its done by GM in Oz where temps are pretty hot too.

KraZy

iTrader: (4)

Why does it buck when its running that lean?

Thanks for the offer ZL1Killa, I hope your project is going well.

wicked_95z

iTrader: (8)

Because you are causing a cylinder power imbalance. If it is detonation you have the air fuel mixture igniting early and actually pushing against the piston. If it is a misifre then instead of having the piston pushed back down it has to be pulled back down throwing the balance off

jay_99z

iTrader: (5)

Could be the converter locking and unlocking......if it's an aftermarket stall. They can get a little touchy sometimes if you are way off on the tune. Misfires, knock, etc.

xaon

iTrader: (12)

it bucks because it is misfiring and flipping the Air Fuel Ratio all over the place.

It was not uncommon for mine to jump around from 18:1 down to 13:1... Makes it shudder and buck like a mule (and this is a 6-speed car).

I richened mine up a hair and added some more timing in to stabilize the cruising.