It turns out there is an idle air control valve on the intake manifold that is sealed with an oring, but it's not in a flat groove that is pressed down by the bolts, it's in a groove on the IAC valve and fits into a bore on the intake manifold. Even though I doubt that valve has ever been taken out, the oring was hard, flat and shrunk and when I took the valve out you could feel that it wasn't making any contact. I put a new oring on it that wasn't even the right size (it was a cap oring from a pentastar oil filter cap) and the code went away and LTFT is back to zero at idle.
What does LTFT mean?
- Thread starter LavaRand
- Start date
Thanks for posting the conclusion, makes threads like these much more valuable.
Posts of fixes like #21 make me wish there was a "10X LIKE" button.
LTFT is used on cold start up to determine air/fuel ratio when in Open loop mode.. When most monitors become ready the computer goes into Closed loop with active monitoring. Cold start does not mean really freezing cold
This is incorrect. O2 sensors are not used it open loop so it does not care what the fuel trims are in open loop. It pulls from a set of pre programmed fuel/air metering tables in open loop and then relies on o2 sensors, MAF/MAP etc for fuel adjustments once in closed loop.
you failed to understand my post. LTFT the values stored become the startup defaults in open loop, i NEVER mentioned O2 sensors ,only that as various MONITORS set such as O2 heaters, coolant temp ambient air to intake air etc the computer will then enter closed loop and actively monitor air/fuel ratio and actually toggle the ratio to lean then rich.. Using an scope you can clearly see the toggling, which is used in most 3 bed converters to clean up the oxides of combustion.
