o2 sensor missfire, need new tune?
o2 sensor missfire, need new tune? I have an 01 z28 6spd bolt on car Hooker LTs off road Y LM1 SLP lid BBK 80mm TB MAF Housings MSD 8.5 wires E3 spk plugs Rear o2s deleted. Recently I had a o2 sensor go bad bank 2 sensor 1 low voltage code and for bank 1 sensor 1 low switching car went to limp home mode suddenly misfiring all over the place SES light blinking car had no power was afraid to hit the gas. I work at a repair shop so I pulled the codes came back 1153 Slow switching o2?? and p0152 low voltage o2??. so I replaced both of them with BOSCH ones, car ran fine for a few days than it started acting up again out of nowhere misfiring(feels like) no power in any gear feels like death than goes back to normal just as sudden sometimes I have to shut it off and start it again. The car feels fine when its running normal pulls hard at WOT sometimes a little minor hesitation at part throttle. also it smells a lot like gas while I'm sitting still or after I shut it off, I had feared it was running rich before the o2s went bad but thought replacing them would fix that. I had a previous tune done at a shop after I did my headers a/f was good for a street car the tuner never said anything to me about it being rich and I was happy with the numbers, he deleted the rear o2s and skip shift and all the other basics of a tune, car was fine untill the o2s went bad. My question is, is it my tune do I need a new tune? can the o2 codes be tuned out and is that whats making the car miss and run like crap than go back to normal suddenly or what else could it be o2 extensions a bad new o2? any thoughts are greatly appretiated thanks for the help in advance.
Your car running like crap is what is probably making the O2's act up. Fix the problem that is messing up the O2's first. Did you go thru the diagnostics or just put the sensors in?
go to gearchatter.com and follow the steps for the codes.
go to gearchatter.com and follow the steps for the codes.
"MAF housings" (just like ported MAF) may skew
mixture lean. O2 codes don't always mean what
they say. A misfire can really screw up mixture,
so can things like single-runner intake manifold
leaks. Looking at single cylinder misfire rates at
idle and low throttle can point you at a bad
cylinder if there is one.
Cylinder imbalances can result in one lean, three
fat so you get the gas smell and stumble, both.
Gas smell is HC emissions which can come in at
either end of too-rich or too-lean. An acidic
exhaust is lean (NOx) and one that smells "dead"
or "sweet" is rich (CO).
Check misfire rates and maybe do a cylinder
balance test if your scan tool supports that.
Probably runs crappy in closed loop and good
in open loop because something is tricking the
O2s. Chasing down what, is the thing.
mixture lean. O2 codes don't always mean what
they say. A misfire can really screw up mixture,
so can things like single-runner intake manifold
leaks. Looking at single cylinder misfire rates at
idle and low throttle can point you at a bad
cylinder if there is one.
Cylinder imbalances can result in one lean, three
fat so you get the gas smell and stumble, both.
Gas smell is HC emissions which can come in at
either end of too-rich or too-lean. An acidic
exhaust is lean (NOx) and one that smells "dead"
or "sweet" is rich (CO).
Check misfire rates and maybe do a cylinder
balance test if your scan tool supports that.
Probably runs crappy in closed loop and good
in open loop because something is tricking the
O2s. Chasing down what, is the thing.
Thanks for your input. How do i know when its running in open or closed loop, and if all the wires are ok and I put the stock MAF can this be a problem a tune would fix?
