Engine warmup

[Mark Eidson]

At 10:13 AM 1/12/97 -0500, you wrote:
>Here is a couple of thoughts or questions:
>
>1- I assume you can't adjust at what temp. you can go to closed loop

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

The feedback target voltage can be set for idle, up to 1200RPM, and then 4
steps over the MAP range above 1200 RPM.  There is a 16x16 fuel map and the
enrichment can be set for every 10 degrees f from -40 to 240.  Setting the
target voltage to 0 for any given area opens the feed back loop.  There is
also full control of ingition advance based on RPM and throttle position.
>
>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.
>
The O2 sensor is self heating and provides good data long before the loop is
closed.  The relay should work.  I was hoping to find a way to do it with
the adjustments available with the system.
>
>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
>> ***************************************************************************
>> * Mark Eidson                        Voice: (602)752-6513                 *
>> *                                      Fax: (602)752-6000                 *
>> * Manager System Integration and      Home: (602)831-6079                 *
>> *   Verification                    E-Mail:  mark.eidson at tempe.vlsi.com   *
>> * VLSI Technology, Inc.                                                   *
>> * 8375 South River Parkway                                                *
>> * M/S 265                                                                 *
>> * Tempe, Arizona     85284                                                *
>> ***************************************************************************
>
>
***************************************************************************
* Mark Eidson                        Voice: (602)752-6513                 *
*                                      Fax: (602)752-6000                 *
* Manager System Integration and      Home: (602)831-6079                 *
*   Verification                    E-Mail:  mark.eidson at tempe.vlsi.com   *
* VLSI Technology, Inc.                                                   *
* 8375 South River Parkway                                                *
* M/S 265                                                                 *
* Tempe, Arizona     85284                                                *
***************************************************************************