now that my rebuilt engine and trans are running again, i have a ? regarding code 44&45 for lean/rich conditions. the eng has NOT been "tuned" yet, but it was in the shop to have it checked out after the rebuild way back when. i was told everything was good to go, but idle was a little lean. so my ? is what conditions have to be met to cause those codes to pop? i have everything pretty well set, timed, etc. and seems to be running good. i am just wondering how lean or how rich it has to be to trigger the code. the reason i'm asking this now is because i won't be able to get it to a dyno right away and would like to be able to drive it in the meantime. on the other side of the coin, i don't want to potentially harm anything, either. i don't want to assume it's neither too lean nor too rich because the codes aren't out there. i did confirm that it is running in open and closed loop, so...

another ? i have is what scan tool would i need to read the ecm and how "simple" is it? i'm not familiar in this territory, but can learn... the vehicle it's for is my '91 5.7L TPI... thanks for any help.

 

The 44 & 45 codes are O2 sensor lean and O2 sensor rich (not necessarily in that order). For these to occur the value reported by the O2 sensor has to be 'stuck' at one extreme or the other for a period of time. This also means that the BLMs will be at there maximum or minimum (lean or rich correction) value while not providing enough correction to bring the fueling back in line.

For a scan tool, if you have a laptop, is to get Moates ECM853 program. Can be found on moates.net and is free. It is a DOS program and works rather well. It will allow for both trouble shooting and data logging. A $50 laptop is all that is required to use it.

RBob.

 

i have a laptop for this... where do i get the cables, or do they have to be made?

and i guess there's not much risk with driving it? common sense approach, but just clarifying...