[T3] Still trying to figure out the 73 T-3 FI issue

William J catnine09 at dslextreme.com
Mon Jan 1 13:48:49 PST 2018

  I brought up unplugging the air temp sensor . So far this does make the engine run fine.

 One thing that remains as before. When I first start it cold after a few minutes the idle increase's by 200 RPM then after a while it drops down . I had to set the idle lower because of the increase with the air temp sensor unplugged. 

 I know more air = more fuel not richer like a vacuum leak would cause.

 Is it the time the head temp sensor heats up added to the time the AAR is open so you have more fuel which is richer and more air because of the AAR being open.

 This is the part that does not make sense. Cold the AAR is open = more air yet why would the idle increase 200 RPM not right away yet after a few minutes? 

 I know there is some spec at what point the HTC at certain temps reads an ohm drop and some spec on how long an electric AAR stays open and gradually closes. 

 The AAR seems to be closing yet not in the 12 minute so called time frame . It seems to vary since it may stick. I'm not even certain the RPM sould rise at all with the AAR open . Some say it will and others say it is only supposed to allow more air to compensate for the HTC richer mix. 

 I seem to recall before that the idle cold did not raise. 

 It's not that the engine stalls. 

 I have runner sleeves coming and a few head to exhaust gaskets because there is an exhaust leak where the right heat exchanger fits the EMPI header . I need to remove that and see if the thin aluminum sheet I have will take up that gap. I also want to replace the sleeves and any vacuum hoses that are old which are the auto trans lines and AAR to IAD. And last see if the PCV is an issue in some way. Also while the runners are off replace the oil cooler seals which is no something I look foreward to. I haven't had the tin off in a long time and can't recall if the left upper tin can come off just by remoing the screws on the fire wall tin just enough to sneak the left upper tin out. 

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