H@xtGSX
10+ Year Contributor
- 1,093
- 11
- Aug 9, 2011
-
Carlsbad,
New Mexico
Ok, I did the 10k potentiometer mod after my 1g CAS swap and have had no problems with it so far. I've searched and had about 90% of my questions answered, but I want some verification of my methods because I don't have the gauge for my wideband yet and I really don't want to do any damage to this motor after all the work I've done to it.
Background: I already live at ~4000 ft. elevation, so I didn't have to add a whole lot of resistance before the p0300 code stopped popping up, but it was enough that it leaned out the fuel more than I was comfortable with. I can't tell you exactly how much it leaned out, but it idled rough, was real jumpy from being lean, and heated up too quick for comfort. I adjusted up a couple percent on the SAFC to compensate and it seems to be running just about right. I have an OBD scanner/logger that I can watch and track the O2 voltage front and back, the timing changes, the coolant temps, and see how both the ST & LT fuel trims are changing as I drive. My CAS is set to match the ECU base timing at 5 degrees. The timing advance curve past 3000 rpm at WOT dips to ~15 as boost rolls past 10 psi and advances fairly smooth to around 28.5 at 6000 rpm. I think I have a little knock around 5000, but I'm not positive. The timing will drop back a little approaching 5000 though, and then continues on up to about 28.5 around 6000.
The Questions: If you are tuning without a wideband (if you can call that tuning and not dangerous guesswork), can you gauge if the SAFC correction is right by a steady near 0% fuel trim? Is the timing I'm seeing in the upper rpm too high? (it doesn't seem like it... the timing doesn't bounce around too much)
Background: I already live at ~4000 ft. elevation, so I didn't have to add a whole lot of resistance before the p0300 code stopped popping up, but it was enough that it leaned out the fuel more than I was comfortable with. I can't tell you exactly how much it leaned out, but it idled rough, was real jumpy from being lean, and heated up too quick for comfort. I adjusted up a couple percent on the SAFC to compensate and it seems to be running just about right. I have an OBD scanner/logger that I can watch and track the O2 voltage front and back, the timing changes, the coolant temps, and see how both the ST & LT fuel trims are changing as I drive. My CAS is set to match the ECU base timing at 5 degrees. The timing advance curve past 3000 rpm at WOT dips to ~15 as boost rolls past 10 psi and advances fairly smooth to around 28.5 at 6000 rpm. I think I have a little knock around 5000, but I'm not positive. The timing will drop back a little approaching 5000 though, and then continues on up to about 28.5 around 6000.
The Questions: If you are tuning without a wideband (if you can call that tuning and not dangerous guesswork), can you gauge if the SAFC correction is right by a steady near 0% fuel trim? Is the timing I'm seeing in the upper rpm too high? (it doesn't seem like it... the timing doesn't bounce around too much)
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