Quote:
Originally Posted by Kingtal0n
the fuel trim looks right, ill assume 100 = untouched (100% fuel from the map). When you step down on the TPS it locks at 100 because the ECU stops looking at the narrowband during open loop. Assume when you see 100 fuel trim you are in open loop.
While the fuel trim is 97 Ill assume that 3% fuel has been removed. Basically not important. the ECU is not pulling that much and it has a max adjustment anyways to prevent a bad O2 sensor from causing serious problems.
focus on the scenario:
lets scenario. Your driving at constant throttle. The O2 sensor is flipping back and forth. You keep driving this way forever. Suddenly out of no where- the car acts up? For how long? If you just keep your foot there, does it start working again like normal?
compressor surge shows up on the maf signal- see the jagged edges?
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Ahh see that's where you're wrong! This is during (supposedly) CLOSED LOOP. Not open loop. (Yes 100 is 100% of the base map).
The TPS voltage you see here is only 1.1. This is basically 15% throttle, just enough to barely accelerate in 2nd gear.
If I open up map trace, it actually shows me in closed loop during the stumble.
focus on the scenario:
I apply 15% throttle at 2500-3000 RPM, attempting to maintain constant speed. Everything is normal for about 1 second, narrowband oscillated at an average of 0.5. Then narrowband all of a sudden goes 100+, wideband jumps to 17.2, 1 more second, wideband jumps to 20. Car starts stumbling. Car will KEEP stumbling (misfiring) if I do not move throttle. I don't let it do this for too long. I usually just floor it for 1 second from here on to throw it into open loop and give it more fuel. The only way to maintain highway speed safely is to drive 0% throttle / 100% throttle.