Engine warmup

[Mazda Ebrahimi]

Here is a couple of thoughts or questions:

1- I assume you can't adjust at what temp. you can go to closed loop

2- When you talk about adjusting mixture, does that include shifting 
feedback target voltage, or is it just the base fuel curve.

3-  Does the system go to closed loop regardless of O2 volts?  A lot of 
systems do not go to closed loop (even after they are supposed to based 
on the temperature run time table) until there is some voltage on the O2 
sensor input line.  This is done to make sure the sensor is warm.  If 
that's the case, may be you can disconnect the sensor line through a 
relay that is activated by a temperature switch set at 80 degrees or 
something.
 

Mark Eidson wrote:
> 
> My Holley Projection throttle body controller turns on O2 feedback while
> warmup enrichment is still on.  The effect leans our the mixture and I get
> an occasional backkfire during gear shifts, an automatic transmission.
> There is no way to change the closed loop turn on, when the engine temp
> reaches 70 degrees.  Holley suggested just enriching the warmup in the area
> where the backfire occurs.  This helped some but I still get an occasional
> backfire or hesitation.  Should I just keep upping the enrichment or are
> there other ways to help the problem?  me
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