Thread: Any Newbie to GTP tuning tips, as far as what NOT to do??

Buy 2 spark plug non foulers for 6$
Drill threw one with a 1/2 bit
put o2 sensor in the drilled one
put drilled one in non drilled one
put non drilled one in o2 bung

Originally Posted by Ginseng

Buy 2 spark plug non foulers for 6$
Drill threw one with a 1/2 bit
put o2 sensor in the drilled one
put drilled one in non drilled one
put non drilled one in o2 bung

I did that right now with the bad cat I have. It hasn't set the P0420 yet but it's been thru like 5 drive cycles also and the monitor hasn't gone to ready. It will eventually, if you watch the back sensor with a scan tool it looks just about spot on.

I am thinking I have another issue...

Doing some basic maintenance, we changed all the fluids, and of course, oil, trans. and fuel filters.

The MAF sensor AND front O2 sensor are both a month old.

When we first got car, it kinda bucked on light throttle take off from a dead stop. Was getting MAF code....can't remember number though.

I bought aftermarket MAF and cleared code...all seemed good to go.

Few days later got the P0420 code, so just went ahead and swapped in a new Bosch O2 sensor.

Car RUNS GREAT, but keeps getting P0171 and P0420 codes after 4 or 5 drive cycles.

Fast forward to yesterday...

Bring home my scanner since it now has an ABS code.
I also do a live data scan and see front O2 is staying very low voltage at idle, like .120v or less, and rear O2 is staying right near the same....very little fluctuating, and DEFINITELY NOT any rapid, NORMAL O2 voltage movement...

I disabled MIL so it will pass emissions inspection (since it is due now).

But I am a little puzzled why it is idling so lean, and getting very little O2 sensor sweep????

Any ideas?? On what to check, or look for??

Only "MOD" under the hood (done by us) is an aftermarket intake tube and conical air filter.

Thanks.

p.s. I can post up the HPTuner file when I get home, but it's all stock tune, aside form slightly lower fan settings and now the P0171/P0420 codes disabling the MIL light. That's it. I noticed an HPTuners datalog shows high ST and LT fuel trims, as well as little to no fluctuation, so I assume that is from the lean O2 voltages? Just have no idea where to look for the ROOT problem....somehow it manages very good MPG's still...