- Joined
- Aug 6, 2007
- Messages
- 444
- Reaction score
- 3
- Points
- 18
- Age
- 61
- Transmission
- Automatic
I'm not entirely convinced my new O2 sensor is working. Sometimes it'll come on, but the moment I put my foot into the throttle it begins reading dead rich. Now, fuel economy is terrible, and this has me scratching my head a little bit.
Since I went to BIGGER tubing and a BIGGER throttle body, shouldn't that bump my volumetric efficiency UP, and therefore LEAN my fuel table? It seems to have had the opposite effect, though.
If I run autotune, the tuning utility that comes with the Megatune software I'm using, it puts ridiculous spikes into my fuel table that make the truck run terribly. I've always had better luck tuning it by "feel," and then running a separate analysis based on a datalog, using a program called Megalog Viewer, which has its own VE analysis.
My datalogs, however, are showing the intermittent O2 signal to which I referred earlier, and without that feedback, the computer can't correct the fuel table. So, this morning I leaned out a significant portion of the fuel table by hand. To my surprise, the truck began running much better!
This seems counterintuitive. Worse, the table I'm using had been initially set up with my stock sensor, and when I went to the wideband I found that it didn't need much tweaking. Now, however, it seems like the entire table is too rich. This seems to be confirmed by my dismal fuel economy.
There has to be a way of checking the O2 sensor for proper function . . .
Since I went to BIGGER tubing and a BIGGER throttle body, shouldn't that bump my volumetric efficiency UP, and therefore LEAN my fuel table? It seems to have had the opposite effect, though.
If I run autotune, the tuning utility that comes with the Megatune software I'm using, it puts ridiculous spikes into my fuel table that make the truck run terribly. I've always had better luck tuning it by "feel," and then running a separate analysis based on a datalog, using a program called Megalog Viewer, which has its own VE analysis.
My datalogs, however, are showing the intermittent O2 signal to which I referred earlier, and without that feedback, the computer can't correct the fuel table. So, this morning I leaned out a significant portion of the fuel table by hand. To my surprise, the truck began running much better!
This seems counterintuitive. Worse, the table I'm using had been initially set up with my stock sensor, and when I went to the wideband I found that it didn't need much tweaking. Now, however, it seems like the entire table is too rich. This seems to be confirmed by my dismal fuel economy.
There has to be a way of checking the O2 sensor for proper function . . .