mos
14-05-03, 20:51
Right here goes, i have a wideband o2 and have been doing some monitoring of my narrowband. When the car has been running for a while and then sat at idle or started up after a run and semi cool down i was getting a lumpy idle and have tracked it down to my narrowband not being heated up enough or being cooled down too much by my exhaust gases. Here is how i found out - My wideband was reading 14.7 constantly while my narrowband gauge would slowly drop from stoich to nearly off the gauge lean causing the ecu to think it was lean and try to compensate causing the lumpy idle. The problem will not exist during driving (hotter gases) or start up (again higher idle = hotter gases). The problem also clears if the car is then driven for a short way but again on stopping at idle you can watch the narrowband gauge SLOWLY drop down from stoich to lean to nearly off the gauge again. I am going to try some heat wrap and will post results when i have, in the meantime its something to think about if your idle is lumpy. Anybody with an A/F gauge watch it at idle and if you have this problem it will slowly lean off due to its heat, but as with mine the A/F will still actually be 14.7 but the ecu will become confused.