spacemonkee23
Well-Known Member
What I don't understand is how a vacuum leak can cause it to run rich at idle. A vacuum leak would cause extra air to get in which would lean it out wouldn't it?
Typically, yes. When the ecu sees a lean mixture from the O2 sensor it will try to compensate by adding more fuel but cant compensate for more than a minor leak. Mostly you will see a lean mixture at ilde then it would correct itself at higher RPM. Thats not the case here
I checked the O2 sensor readings using my phone connected to the car's OBDII port and at idle it will hang out at 0.04 volts for a while then jump up to 0.8 volts for a while then back to 0.04 volts. does this sound normal? At some point I want to swap the front O2 sensors between my accords and see if that makes a difference. Also does anyone know where the long coolant line that connects to the IACV goes because I need to replace it on my old sedan. The only way I was able to get the IACV off was to cut the hose. Also how long is it and what size is it?
From what I can tell from this, the O2 sensor is reading a rich condition and switching properly.
Normal readings are typically around .1v Through .9v switching .4v to .8v shows a rich condition along with your LTFT reading of -24 (Rich).
I would try swapping the FPR between cars.
Edit: Plus having dry carbon/black build up on your spark plugs is an obvious rich condition. If the plugs stay wet and are black then you would have an oil issue. Light brown build up is a lean condition.
With a -24 LTFT I wouldn't be surprised if you had black soot coming out of the exhaust at idle. Thats very Rich!
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