The Screw in the AFM [CO] affects the mixture accross the full range [its a seperate air channel that bypasses the barn door flap] However; the ECU has the final say, and will compensate and alter both timing and mixture to be within a pre-determined parameter, especialy if you have a cat and lamba sensor fitted.
Also check the tightness [torque] on the inlet manifold studs.
Hope this helps.
Quote:
Originally Posted by LBEEMING
Hi Team, 3.2 85 btw,
Hoping someone can chime in on this. I am told that once the engine gets to about 70 deg the O2 sensor kicks in and adjusts idle, but during cold it's all about these two mixtures.
Am I right in thinking that AFM screw is purely for CO value at idle and the idle screw is only for adjusting idle when ICV is disconnected.
Issue I am having is that at cold start rpm hunts between 900 to 1100 for 10 seconds, then drops to 650. Once warm it idles fine at 850.
Now if I turn down the idle screw half a turn, it will start and sit at 1100 steady then drop even lower to 600 rpm till warm.
I'm wondering if my base idle AFM setting is too rich and that's forcing the idle to 600 until the O2 sensor kicks in.
Just a theory, have an afr gauge coming so will verify idle afr soon!
FYI - made a home made smoke tester, only leak found was from the air box intake to the airbox itself, nothing after the AFM module. Car drives well, no issues to speak of. Just want to get the warm up cycle 100% sorted. Maybe an exhaust pop every now and then on over run, but I did delete the CAT and have a monty pipe ��
Cheers!
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