This was my first ECM tune from Scratch on a 1227747 using a 29c256 EEPROM and I am happy to say "It PASSED California SMOG with Flying Colors" Keeping this in mind , 2 days later the SES light pops me a code 44 "LEAN or LOW 02 Voltage" Nothing has been touched at all. Upon aldl logging I can start it up cold and watch the o2 count click down to very lean. (I shut it down) Installed a new o2 sensor and no change. Ran and passed smog 2 days ago.......Any thoughts here folks? I am at a loss....Pressure regulator?
I am VERY OPEN to suggestions! Also this settup is all new parts.(ALL)

 

troubleshoot.

If everything was fine before, something else happened.

Bad vacuum leak, any exhaust leak in frt of or near the 02 sensor.

Failing fuel pump, etc.

Regulators usually dont provide less pressur(but not a guarantee) they usually cause enough pressure to flood it out.

I wouldnt trust an 02 reading when cold unless its from a heated 02 or heated wideband.

Run thru the basics to eliminate all the stupid things first.


later
Jeremy

 

Is it possible that lets say the o2 sensor is on the right side of the engine and one had a lean injector or too small of one on the left side. That the o2 would not be picking it up per say. I mean logging wise in winaldl? The exhaust join together after the o2 sensor. Otherwise I am down to the pressure regulator or fuel pump depending on my FP reading here I am about to check. Also pulled plugs from both sides and the left is very white compared to the almost white on the right. 3.8TransAm thank you for your reply it is much appreciated. After you stair at this for so long it all gets cloudy, I'm sure you can relate to such problems. LOL! Thanks TGO for your Help!

 

The new fuel pump was only putting out 5 pounds pressure. New parts. HAH!
Thanks for the help anyway TGO & KUTGW!!!!