half-n-half

iTrader: (7)

here is what my car was doing...i would drive teh car for a couple of seconds everything would run great. it would then start to missfire horribly. i never knew why. well...

today i got a scantool and checked some things out on the drive home...

What i have come up with is teh following....:

The only time my car missfires is if it is closed loop. Whenever it is in closed loop mode my short term fuel trims bank 2 will begin to work its way to -40% and then the car will start to miss real bad. the trim will stay at -40% until i give it a little gas to "power through" the missfire and then the fuel trim will back to low negatives numbers like the rest of them...


What does this mean...i have no idea.
It also says that fuel system 1 and 2 are both in fault regardless of OL or CL.

When in OL all the fuel trim tables sit right at 0% and it runs great....

i dunno hopefully i can get some help.
Thanks

BTW DTCs were...
1133
1153
0300
0140
0160

Thanks
Louie
__________________

bmfcamaro

iTrader: (1)

scan the o2 sensors with a chart display and see if they are active.

half-n-half

iTrader: (7)

ok, what should i look for?
i can see that the driver side 02 sensor does change from .3 volts to like .7 voltsif i rev the engine, however the passenger side does not seem to vary...maily right around .6volts.

is the driver side acting coreectly? are they both bad.

What should happen when they are active?

Thanks
Louie

Thanks for the help i would really like to get to the bottom of this. believe it or not i was just getting ready to change the pass side 02 to see what happens...

half-n-half

iTrader: (7)

ok well i checked the 02 sensors and the passenger side o2 was not fluctuating at all.

changed that sensor out, and even when in CL mode it ran great again, however it willnot stay in closed loop mode...it always goes back to open loop.

Will the p0140 and p0160 codes send it to open loop mode all the time?

i also know that it has the switching problem...which bring me to my next problem...

neither of the o2 sensors voltage drops below .300 volts, which causes the non-switching code.

now if it were due to an exhaust leak it would show a lean condition at the 02 sensor right?
but if my engine were out of tune due to the lid and the exhaust it could show a constant rich condition.

one way to kind of test my theory i unscrewed the tube after the MAF and jammed an extension in there to allow a small amount of unmetered air in. after doing this both 02 sensors read about .1v less.
driver side started to read as low as .285v at idle, and passenger side started to read at around .370 volts at idle.

Tell me what you think....maybe just need a tune for teh 1133 and 1153 codes?

Thanks
Louie