Closed loop mode. Is this true?
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The reason ECT is important is because many engines need an extra rich AFR in order to stay lit at cold temperatures.
Many engines fail smog because of this.
Many engines fail smog because of this.
Originally Posted By: Gary Allan
Err..I didn't read into every detail here ..but you appear to be talking about closed loop being "enabled" ..not being in closed loop ..which unless you've got some trick system, you're not in all the time.
The literature I've read said the TL is in feed back operation with the cats lit off (and obviously the 02s) within 10 seconds or close to it. This doesn't mean it's not running rich still, just that it's in feedback mode. It's factory equipped with a wideband 02 so the rich running is still precisely metered.
Interestingly while cold, it doesn't pull throttle on the upshifts like it normally does.
Err..I didn't read into every detail here ..but you appear to be talking about closed loop being "enabled" ..not being in closed loop ..which unless you've got some trick system, you're not in all the time.
The literature I've read said the TL is in feed back operation with the cats lit off (and obviously the 02s) within 10 seconds or close to it. This doesn't mean it's not running rich still, just that it's in feedback mode. It's factory equipped with a wideband 02 so the rich running is still precisely metered.
Interestingly while cold, it doesn't pull throttle on the upshifts like it normally does.
Thanks guys for all the input.
Just in case anyone is interested, here is the original thread in question.
http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=1658055#Post1658055
Just in case anyone is interested, here is the original thread in question.
http://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=1658055#Post1658055
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If you are the guy with the EEC-IV car, then the ECT plays a role. Download the GUFB and read it. It's basically the EEC-IV bible.
http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings/
And there is some more information.
Quote:
Closed Loop
When the EEC reaches a point where it is satisfied with all monitored parameters, it will transition to closed loop operation. In this mode the EEC tries to control air/fuel mixture to the stoichiometric ratio of 14.7:1 and accomplishes this by adjusting injector pulse width with feedback from the O2 sensors to control to the 14.7:1 ratio. This will occur when the EEC table values are calling for the ratios close to stoichiometric 14.7:1 air/fuel ratio. In warm up mode or WOT the O2 sensors are not used because they can only send signals that indicate a ratio above or below 14.7:1 and cannot read a ratio directly. You’ll see in the table that ratios in these operating areas are outside the 14.7:1 range. In graphing the parameters of thousands of data samples during closed loop operation, we have seen the EEC go into closed loop at a temperature less than 170°F since Rick Wagner sent more data from the last revision. When temperature gets to 190°F, the A9L EEC pulls 2° of timing, so a 180°F thermostat is probably the best performance choice. Here are a couple of Tweecer data graphs.
It depends on the ECM and software version as to when OL is "allowed" to happen, but temp is definitely one of the parameters.
http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings/
And there is some more information.
Quote:
Closed Loop
When the EEC reaches a point where it is satisfied with all monitored parameters, it will transition to closed loop operation. In this mode the EEC tries to control air/fuel mixture to the stoichiometric ratio of 14.7:1 and accomplishes this by adjusting injector pulse width with feedback from the O2 sensors to control to the 14.7:1 ratio. This will occur when the EEC table values are calling for the ratios close to stoichiometric 14.7:1 air/fuel ratio. In warm up mode or WOT the O2 sensors are not used because they can only send signals that indicate a ratio above or below 14.7:1 and cannot read a ratio directly. You’ll see in the table that ratios in these operating areas are outside the 14.7:1 range. In graphing the parameters of thousands of data samples during closed loop operation, we have seen the EEC go into closed loop at a temperature less than 170°F since Rick Wagner sent more data from the last revision. When temperature gets to 190°F, the A9L EEC pulls 2° of timing, so a 180°F thermostat is probably the best performance choice. Here are a couple of Tweecer data graphs.
It depends on the ECM and software version as to when OL is "allowed" to happen, but temp is definitely one of the parameters.
Thanks for the link.
No, I have not posted in that forum yet. I was just reading there and I struck me as odd that someone who is supposed to be a forum "expert" was putting out misinformation.
Personally I don't really care when my cars go into closed loop, it is more the correctness (or lack there of) that I am concerned about.
No, I have not posted in that forum yet. I was just reading there and I struck me as odd that someone who is supposed to be a forum "expert" was putting out misinformation.
Personally I don't really care when my cars go into closed loop, it is more the correctness (or lack there of) that I am concerned about.
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